Chicken breeding in Japan dates back to fourth century BCE

Conclusive evidence of chicken breeding in the Yayoi period of Japan has been discovered from the Karako-Kagi site.

The chicken is one of the most common domesticated animals, with a current estimated population of over 33 billion individuals. They are reared for their meat and eggs, and may be kept as pets.

The chicken is believed to have been domesticated in Southeast Asia about 3500 years ago, following which they were carried to all corners of the world. The exact date of introduction of chicken breeding to Japan is under debate, as there are no historical records and archeological evidence is inconclusive.

Professor Masaki Eda at the Hokkaido University Museum led a team to uncover the earliest conclusive evidence of chicken breeding in Japan. The findings, which show chickens were bred in the Karako-Kagi site, a settlement from the Yayoi period [5th century BCE to around 2nd century BCE], were published in the journal Frontiers in Earth Sciences.

"Chickens and their wild relatives belong to a family of birds called Phasianids, which includes pheasants, turkeys and quail," explains Eda. "Bones of juvenile phasianids recovered from archeological sites could not indisputably be identified as belonging to chickens or to similarly sized wild pheasants. Identification of juveniles is important, as it would indicate that breeding of chickens took place."

The Karako-Kagi site, in what is now Tawaramoto Town, Nara Prefecture, is considered to be a settlement that played the role of a leader of the Kinki region during the Yayoi period. There are multiple archeological digs in the area; one such dig, at the 58th research point, yielded ten phasianid bones, four of which belonged to juvenile birds.

The team used a technique called Zooarchaeology by Mass Spectrometry (ZooMS) to analyze the collagen in two of the juvenile phasianid bones. Previous work by Eda had shown that domestic chicken and Japanese wild pheasants had different ZooMS fingerprints; ZooMS revealed that both the two bones belonged to chickens. The collagen from one of the bones was also carbon dated to 381-204 BCE, corresponding to the middle Yayoi period.

"Ten of the eleven previously-discovered bones of adult chickens from this period have all belonged to males; hence, it was thought chicken breeding could not have occurred on the Japanese archipelago," Eda elaborated. "By identifying bones from juvenile chickens, we provide clear evidence that breeding did occur in that time period -- which is also the earliest time chickens could have been introduced to Japan. In addition, Karako-Kagi is considered an important trade hub of the Yayoi period, so there is a possibility that this status is a factor in chicken breeding during the period."

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Change in bird coloration due to climate change

The work, which was conducted over a 15-year period (2005-2019) through a partnership between scientists from the UPV/EHU and the Centre d'Ecologie Fonctionnelle et Évolutive in Montpellier (CEFE-CNRS), focused on two populations of blue tits in the south of France, one located on the outskirts of Montpellier and the other in the northwest of the island of Corsica.

Each year between 2005 and 2019, all breeding blue tits in each population were captured. As a result, researchers from the two institutions were able to gather more than 5,800 observations on the colouring and other characteristics of the blue tits.

The blue tit is characterised by its striking colouring: a blue crest and a yellow breast. The results obtained in the study show a decrease in both populations of blue and yellow colouration between 2005 and 2019. In other words, the blue crests and yellow breasts of blue tits in these two populations are on average less colourful right now than when the research began.

"Our work suggests that environmental changes, and specifically climate change, could be the main reason why birds such as the blue tit are undergoing a change in their physical features, more specifically in the brightness and intensity of their colouration," said David López-Idiáquez, researcher in the UPV/EHU's Department of Plant Biology and Ecology.

"A negative trend in terms of brightness and intensity of plumage colouration in both sexes and populations has been observed, although in Corsica this change is more associated with climate," explained López." The change in plumage colour seems to be the result of a combination of a rise in temperature (1.23ºC) and a fall in rainfall (0.64 mm), so climate change would be the potential cause of this difference," he said.

Change in species mating patterns

It may appear to be a purely aesthetic change, but just the opposite is true, as this change in plumage may have an effect on the "mating patterns" of the species. "In these birds, traits such as colouring function as signals to indicate to other individuals the quality of the specimen, which are decisive, for example, when it comes to breeding," explained David López.

"This study was possible thanks to the continuous monitoring of the two blue tit populations for more than 15 years, which highlights the importance of long-term studies to understand the effects of climate change on the ecosystems around us," he said.

When there is a variation in the territory, animal populations have 4 options: the first is to undergo genetic change; the second is to undergo plastic change (change in physical characteristics without genetic changes); the third is to migrate; and the last, to disappear. "It is important to stress that this change is not genetic but plastic, one of the ways of adapting to new environmental conditions," he pointed out.

Change in our environment

"Given that our environment is quite similar, albeit less hot, our birds may be undergoing the same change," surmised David. "In any case, there are only four studies of this type in the world, and none of them has been carried out in the Basque Country; I think it would be very interesting to carry out more research like this not only on a Basque level, but also on a national level," he added.

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World's largest fish breeding area discovered in Antarctica

Near the Filchner Ice Shelf in the south of the Antarctic Weddell Sea, a research team has found the world's largest fish breeding area known to date. A towed camera system photographed and filmed thousands of nests of icefish of the species Neopagetopsis ionah on the seabed. The density of the nests and the size of the entire breeding area suggest a total number of about 60 million icefish breeding at the time of observation. These findings provide support for the establishment of a Marine Protected Area in the Atlantic sector of the Southern Ocean. A team led by Autun Purser from the Alfred Wegener Institute publish their results in the current issue of the scientific journal Current Biology.

The joy was great when, in February 2021, researchers viewed numerous fish nests on the monitors aboard the German research vessel Polarstern, which their towed camera system transmitted live to the vessel from the seabed, 535 to 420 metres below the ship, from the seafloor of the Antarctic Weddell Sea. The longer the mission lasted, the more the excitement grew, finally ending in disbelief: nest followed nest, with later precise evaluation showing that there were on average one breeding site per three square metres, with the team even finding a maximum of one to two active nests per square metre.

The mapping of the area suggests a total extent of 240 square kilometres, which is roughly the size of the island of Malta. Extrapolated to this area size, the total number of fish nests was estimated to be about 60 million. "The idea that such a huge breeding area of icefish in the Weddell Sea was previously undiscovered is totally fascinating," says Autun Purser, deep-sea biologist at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) and lead author of the current publication. After all, the Alfred Wegener Institute has been exploring the area with its icebreaker Polarstern since the early 1980s. So far, only individual Neopagetopsis ionah or small clusters of nests have been detected here.

The unique observations are made with a so-called OFOBS, the Ocean Floor Observation and Bathymetry System. It is a camera sledge built to survey the seafloor of extreme environments, like ice-covered seas. It is towed on a special fibre-optic and power cable normally at a speed of about one half to one knot, about one and half metres above the seafloor. "After the spectacular discovery of the many fish nests, we thought about a strategy on board to find out how large the breeding area was -- there was literally no end in sight. The nests are three quarters of a metre in diameter -- so they are much larger than the structures and creatures, some of which are only centimetres in size, that we normally detect with the OFOBS system," Autun Purser reports. "So, we were able to increase the height above ground to about three metres and the towing speed to a maximum of three knots, thus multiplying the area investigated. We covered an area of 45,600 square metres and counted an incredible 16,160 fish nests on the photo and video footage," says the AWI expert.

Based on the images, the team was able to clearly identify the round fish nests, about 15 centimetres deep and 75 centimetres in diameter, which were made distinct from the otherwise muddy seabed by a round central area of small stones. Several types of fish nests were distinguished: "Active" nests, containing between 1,500 and 2,500 eggs and guarded in three-quarters of the cases by an adult icefish of the species Neopagetopsis ionah, or nests which contained only eggs; there were also unused nests, in the vicinity of which either only a fish without eggs could be seen, or a dead fish. The researchers mapped the distribution and density of the nests using OFOBS's longer-range but lower-resolution side scan sonars, which recorded over 100,000 nests.

The scientists combined their results with oceanographic and biological data. The result: the breeding area corresponds spatially with the inflow of warmer deep water from the Weddell Sea onto the higher shelf. With the help of transmitter equipped seals, the multidisciplinary team was also able to prove that the region is also a popular destination for Weddell seals. 90 per cent of the seals' diving activities took place within the region of active fish nests, where they presumably go in search of food. No wonder, the researchers calculate the biomass of the ice fish colony there at 60 thousand tonnes.

With its biomass, this huge breeding area is an extremely important ecosystem for the Weddell Sea and, according to current research, likely to be the most spatially extensive contiguous fish breeding colony discovered worldwide to date, the experts report in the publication in Current Biology.

German Federal Research Minister Bettina Stark-Watzinger said: "My congratulations to the researchers involved on their fascinating discovery. After the MOSAiC expedition, German marine and polar research has once more reaffirmed its outstanding position. German research vessels are floating environmental research laboratories. They continue to sail the polar seas and our oceans almost non-stop, serving as platforms for science aimed at generating important findings to support climate and environmental protection. Funding by the Federal Ministry of Education and Research (BMBF) provides German marine and polar research with one of the most state-of-the-art research vessel fleets worldwide. This discovery can make an important contribution towards protecting the Antarctic environment. The BMBF will continue to work towards this goal under the umbrella of the United Nations Decade of Ocean Science for Sustainable Development that runs until 2030."

For AWI Director and deep-sea biologist Prof. Antje Boetius, the current study is a sign of how urgent it is to establish marine protected areas in Antarctica. "This great discovery was enabled by a specific under-ice survey technology we developed during my ERC Grant. It shows how important it is to be able to investigate unknown ecosystems before we disturb them. Considering how little known the Antarctic Weddell Sea is, this underlines all the more the need of international efforts to establish a Marine Protected Area (MPA)," Antje Boetius classifies the results of the study, in which she was not directly involved. A proposal for such an MPA has been prepared under the lead of the Alfred Wegener Institute and is defended since 2016 by the European Union and its member states as well as other supporting countries in the international Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR).

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Male spiders are attracted by a female like planets orbiting a star

The tiny male golden orb-weaving spider faces a considerable challenge when searching for a mate. He is a fraction of the size of the massive female, but must carefully enter her web and approach her without being noticed, because the cannibalistic female will kill and eat him if he makes one wrong move on her web. Add to this gamble the competition he faces from other males also on the delicate arena of the web, and you have a complex optimization problem that even human analysts would find daunting. Yet these little spiders barely have what we would recognize as a brain. How then do they manage? This is a question that has captivated Alex Jordan and members of his lab at the Max Planck Institute of Animal Behavior for over a decade. Now, teaming up with researchers from the Weizmann Institute of Science, they are closer to an answer.

The solution appears to lie in animal magnetism, or more correctly, in the effective physical forces that males and females experience on the elastic surface of the spider web. "Our initial concept was to explore the idea that these spiders moving on the web behave like electrons orbiting a nucleus, or planets orbiting a star," says Jordan, who leads the Integrative Behavioral Ecology Lab at the Max Planck Institute of Animal Behavior, and is co-senior author on the study. From this initial idea, a research program was born, leading the two teams to develop a physical model and perform experiments in the Panamanian rainforest.

Competitive web arena

While the details of the precise physics ultimately diverged from both atomic and cosmic levels, the concept proved useful. "Imagine electrons orbiting a nucleus, or a massive star in space, so large that it generates its own gravitational field pulling in objects around it -- the giant, cannibalistic female can be thought of in the same way," says Jordan. "Now imagine smaller planets, satellites, or comets coming near this attractive force -- these are our tiny, brave males." Approach the star (or female) too rapidly, or at the wrong angle, and you risk getting caught up in her attractive pull. On a cosmic scale, this will result in a cosmic collision that vaporizes the planet. For the intrepid male, an incorrect approach means falling into a fatal attraction and ending up as prey.

"Working in the rainforests of Panama, I've seen over-zealous males fall victim to the cannibalistic females many times, especially when they take the wrong path, or approach the female too fast," says Sylvia Garza, co-author of the study, who spent months in Panama as a Master's student recording the behavior of male and female spiders, then using machine-learning approaches to track their every movement.

Vibratory cues

Just as the smaller planets have their own gravitational pull, the males also attract one another -- initially approaching the perceived rival. The males also start to repel each other as they get closer and closer, in this way behaving much more like electrons around a nucleus.

"The motion of these males resembles interactions between particles that attract or repel one another depending on the distance between them," says Amir Haluts, a physicist by training and lead author of the study from the Weizmann Institute of Science. Co-senior author Nir Gov, also from the Weizmann, says: "We use models to map the effective physical forces that males experience, allowing us to explain their motion on the web, as well as contest dynamics of males of different sizes." As the males orbit one another, they will eventually come too close together, crashing into each other in open fighting. All this is played out on the surface of the web, which acts as the conduit for the vibrations males use to communicate, but which can also alert the female to their presence and lead to a fatal attack.

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Seven personality and behavior traits identified in cats

Researchers at the University of Helsinki have developed a new comprehensive questionnaire for surveying feline personality and behaviour. A dataset of more than 4,300 cats representing 26 breed groups revealed seven personality and behaviour traits, with significant differences observed between breeds.

Cats are our most common pets, and feline behaviour is increasingly being investigated due to a range of behavioural problems. Another topic of interest in addition to behaviour traits is personality since it can be connected to behavioural problems.

"Compared to dogs, less is known about the behaviour and personality of cats, and there is demand for identifying related problems and risk factors. We need more understanding and tools to weed out problematic behaviour and improve cat welfare. The most common behavioural challenges associated with cats relate to aggression and inappropriate elimination," says doctoral researcher Salla Mikkola from the University of Helsinki and the Folkhälsan Research Center.

Seven feline personality and behaviour traits

In a questionnaire designed by Professor Hannes Lohi's research group, personality and behaviour were surveyed through a total of 138 statements. The questionnaire included comprehensive sections on background and health-related information. By employing, among other means, factor analysis to process the data, seven personality and behaviour traits in all were identified.
 

• Activity/playfulness
• Fearfulness
• Aggression towards humans
• Sociability towards humans
• Sociability towards cats
• Litterbox issues (relieving themselves in inappropriate places, precision in terms of litterbox cleanliness and substrate material)
• Excessive grooming

"While the number of traits identified in prior research varies, activity/playfulness, fearfulness and aggression are the ones from among the traits identified in our study which occur the most often in prior studies. Litterbox issues and excessive grooming are not personality traits as such, but they can indicate something about the cat's sensitivity to stress," Mikkola adds.

Differences in the prevalence of traits seen between breeds

In addition to individuals, clear personality differences can be found between breeds. In other words, certain personality and behaviour traits are more common among certain cat breeds.

"The most fearful breed was the Russian Blue, while the Abyssinian was the least fearful. The Bengal was the most active breed, while the Persian and Exotic were the most passive. The breeds exhibiting the most excessive grooming were the Siamese and Balinese, while the Turkish Van breed scored considerably higher in aggression towards humans and lower in sociability towards cats. We had already observed the same phenomenon in a prior study," says Professor Hannes Lohi from the University of Helsinki and the Folkhälsan Research Center.

The researchers wish to emphasise that no pairwise comparisons between breeds were carried out at this juncture.

"We wanted to obtain a rough idea of whether there are differences in personality traits between breeds. In further studies, we will utilise more complex models to examine factors that affect traits and problematic behaviour. In these models, we will take into consideration, in addition to its breed, the cat's age, gender, health and a wide range of environmental factors," Mikkola says.

Assessing reliability and validity

Feline behaviour and personality can be studied, for example, through questionnaires aimed at cat owners. Such questionnaires can measure feline behaviour in the long term and in everyday circumstances, which is impossible in behavioural tests. Furthermore, cats do not necessarily behave in test settings in a way typical of themselves. Due to their subjective nature, the reliability of the questionnaires must be assessed before the data can be exploited further.

"Internationally speaking, our study is the most extensive and significant survey so far, and it provides excellent opportunities for further research. The reliability of prior feline behavioural questionnaires has not been measured in such a versatile manner, nor are they as comprehensive as this one. Establishing reliability is key to making further analyses worthwhile and enabling the reliable identification of various risk factors," says Lohi.

The researchers reached out to cat owners who responded to the questionnaire one to three months ago, requesting them to fill out the questionnaire again or ask another adult living in the same household to respond to the questionnaire regarding the same cat. The goal was to assess the questionnaire's reliability both temporally and between respondents. Based on two additional datasets accumulated through this method, it was possible to evaluate the reliability of the questionnaire temporally and between respondents.

"By comparing the responses, we noted that the responses provided for the same cat were very similar, while the personality and behaviour traits were found to be reproducible and reliable. We also examined the validity of the questionnaire or whether it measures what it intended to measure. In these terms, too, the questionnaire functioned well," says Mikkola.

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Building bonds between males leads to more offspring for chimpanzees

If you're a male chimp looking for love -- or offspring -- it pays to make friends with other males.

A study led by the University of Michigan, in collaboration with Arizona State and Duke universities, examined why male chimpanzees form close relationships with each other, and found that male chimpanzees that build strong bonds with the alpha male of the group, or with a large network of other males, are more successful at siring offspring. The results are published in the journal iScience.

"One big question that biologists have had for a long time is why you see so many friendly behaviors such as cooperation and alliance in animals," said lead study author and U-M postdoctoral researcher Joseph Feldblum. "One would expect to see these social bonds -- or strong, friendly social relationships -- only if they provide some sort of fitness benefit to the individuals. Males wouldn't spend all this time grooming other males and forgoing trying to find females or food unless you get some kind of benefit from it."

One benefit would be the opportunity to sire more offspring, but no previous studies have looked at the link between social relationships and reproductive success in chimpanzees. Much of the research in this area has been done in female primates, who are primarily concerned with accessing resources in order to reproduce quickly. For males, the biggest task is getting reproductive access to females, says Feldblum, also an assistant professor in the U-M Department of Anthropology and member of the Michigan Society of Fellows.

"Chimps cooperate frequently, and often in these very dramatic ways: You see things like grooming, all kinds of complex alliance formation and group territorial defense," Feldblum said. "The question is: What do males get out of it and how?"

It turns out, they get babies.

One function of these social bonds, the researchers found, is to help males gain access to mating opportunities they wouldn't otherwise be able to get without help from their friends. To examine the link between sociality and paternity success, the researchers examined behavioral and genetic data from a population of chimpanzees living in western Tanzania. The group is part of the ongoing study of chimpanzees in Gombe Stream National Park, begun by Jane Goodall in 1960.

The researchers began by constructing a base model that captures the effects of male age, dominance rank and genetic relatedness to the mother on male siring success. They first used the model to look at 56 siring events with known paternity between 1980 and 2014. Then, they tested whether adding measures of male social bonds to the models improved their ability to predict which male would sire a given offspring.

They found that males with more strong association ties -- males with the highest number of social bonds with other males -- had a higher likelihood of siring offspring. In fact, two or more strong association ties meant a male chimpanzee was more than 50% more likely to sire a given offspring, after accounting for the chimp's age, relation to the mother and dominance rank score.

Next, the researchers wanted to understand how a chimp's relationship to the alpha male underpinned male reproductive success. To do this, they examined the role of strong bonds with the alpha male, looking at 45 siring events by non-alpha males. They generated the same base model, this time comparing the model with models that included several measures of bond strength with the alpha male, among other measures.

The model that fit best included what is called the composite sociality index, which includes grooming and association with the alpha male. It showed that subordinate males with strong bonds with the alpha male, as well as those with many strong association ties, were more likely to sire a given offspring.

"Sucking up to the boss is nothing new," said co-author Anne Pusey of Duke University. "We show that it's always paid off."

But the researchers also found that two factors -- a strong bond with the alpha male and many strong association ties -- both independently contributed to reproductive success.

In animal behavior, coalition formation is when two or more individuals jointly direct aggression toward a third or another group of individuals. According to previous research, individuals that are more central in the network of coalitions tend to rise in rank and sire more offspring.

In the current work, the researchers showed that males who form stronger ties are also more likely to form coalitions, and the researchers hypothesize that this larger alliance network helps males gain mating opportunities. They also found that forming these many strong bonds leads to chimps' improvement in rank within the group; those that made it to the alpha position were also more likely to sire offspring.

A clearer idea of the benefits of social relationships in chimpanzees provides clues about the evolution of friendship in humans.

"Together with bonobos, chimpanzees are our closest living relatives, and help us to identify which features of human social life are unique. This study suggests that strong bonds among males have deep evolutionary roots and provided the foundation for the more complex relationships that we see in humans," said senior author Ian Gilby, a researcher at ASU. "This research also highlights the value of long-term studies like these, which are essential for understanding the biology of a species that lives for many decades and is slow to reproduce."

Feldblum says more research is needed to tease out how coalition formations and these social bonds lead to siring success.

"Is it that if your ally is nearby, you're more likely to mate with an estrus female, or does having your allies around you protect you from harassment from other males?" Feldblum said. "Or because your ally will support you if a conflict erupts, your stress levels are lower and you can devote more energy to mating efforts? This last step we still don't know."

Gilby is an associate professor at the School of Human Evolution and Social Change at ASU, and a research affiliate in the Institute of Human Origins, which curates the data used in this study. Pusey, professor emerita at Duke, has spent the last 30 years of her career assembling, organizing and digitizing this unique dataset.

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All-purpose dinosaur opening reconstructed

 For the first time ever, a team of scientists, led by the University of Bristol, have described in detail a dinosaur's cloacal or vent -- the all-purpose opening used for defecation, urination and breeding.

Although most mammals may have different openings for these functions, most vertebrate animals possess a cloaca.

Although we know now much about dinosaurs and their appearance as feathered, scaly and horned creatures and even which colours they sported, we have not known anything about how the vent appears.

Dr Jakob Vinther from the University of Bristol's School of Earth Sciences, along with colleagues Robert Nicholls, a palaeoartist, and Dr Diane Kelly, an expert on vertebrate penises and copulatory systems from the University of Massachusetts Amherst, have now described the first cloacal vent region from a small Labrador-sized dinosaur called Psittacosaurus, comparing it to vents across modern vertebrate animals living on land.

Dr Vinther said: "I noticed the cloaca several years ago after we had reconstructed the colour patterns of this dinosaur using a remarkable fossil on display at the Senckenberg Museum in Germany which clearly preserves its skin and colour patterns.

"It took a long while before we got around to finish it off because no one has ever cared about comparing the exterior of cloacal openings of living animals, so it was largely unchartered territory."

Dr Kelly added: "Indeed, they are pretty non-descript. We found the vent does look different in many different groups of tetrapods, but in most cases it doesn't tell you much about an animal's sex.

"Those distinguishing features are tucked inside the cloaca, and unfortunately, they're not preserved in this fossil."

The cloaca is unique in its appearance but exhibits features reminiscent to living crocodylians such as alligators and crocodiles, which are the closest living relatives to dinosaurs and other birds.

The researchers note that the outer margins of the cloaca are highly pigmented with melanin. They argue that this pigmentation provided the vent with a function in display and signalling, similar to living baboons and some breeding salamanders.

The authors also speculate that the large, pigmented lobes on either side of the opening could have harboured musky scent glands, as seen in living crocodylians.

Birds are one the few vertebrate groups that occasionally exhibit visual signalling with the cloaca, which the scientists now can extend back to the Mesozoic dinosaur ancestors.

Robert Nicholls said: "As a palaeoartist, it has been absolutely amazing to have an opportunity to reconstruct one of the last remaining features we didn't know anything about in dinosaurs.

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Using math to examine the sex differences in dinosaurs

 Male lions typically have manes. Male peacocks have six-foot-long tail feathers. Female eagles and hawks can be about 30% bigger than males. But if you only had these animals' fossils to go off of, it would be hard to confidently say that those differences were because of the animals' sex. That's the problem that paleontologists face: it's hard to tell if dinosaurs with different features were separate species, different ages, males and females of the same species, or just varied in a way that had nothing to do with sex. A lot of the work trying to show differences between male and female dinosaurs has come back inconclusive. But in a new paper, scientists show how using a different kind of statistical analysis can often estimate the degree of sexual variation in a dataset of fossils.

"It's a whole new way of looking at fossils and judging the likelihood that the traits we see correlate with sex," says Evan Saitta, a research associate at Chicago's Field Museum and the lead author of the new paper in the Biological Journal of the Linnean Society. "This paper is part of a larger revolution of sorts about how to use statistics in science, but applied in the context of paleontology."

Unless you find a dinosaur skeleton that contains the fossilized eggs that it was about to lay, or a similar dead giveaway, it's hard to be sure about an individual dinosaur's sex. But many birds, the only living dinosaurs, vary a lot between males and females on average, a phenomenon called sexual dimorphism. Dinosaurs' cousins, the crocodilians, show sexual dimorphism too. So it stands to reason that in many species of dinosaurs, males and females would differ from each other in a variety of traits.

But not all differences in animals of the same species are linked to their sex. For example, in humans, average height is related to sex, but other traits like eye color and hair color don't neatly map onto men versus women. We often don't know precisely how the traits we see in dinosaurs relate to their sex, either. Since we don't know if, say, larger dinosaurs were female, or dinosaurs with bigger crests on their heads were male, Saitta and his colleagues looked for patterns in the differences between individuals of the same species. To do that, they examined measurements from a bunch of fossils and modern species and did a lot of math.

Other paleontologists have tried to look for sexual dimorphism in dinosaurs using a form of statistics (called significance testing, for all you stats nerds) where you collect all your data points and then calculate the probability that those results could have happened by pure chance rather than an actual cause (like how doctors determine whether a new medicine is more helpful than a placebo). This kind of analysis sometimes works for big, clean datasets. But, says Saitta, "with a lot of these dinosaur tests, our data is pretty bad" -- there aren't that many fossil specimens, or they're incomplete or poorly preserved. Using significance testing in these cases, Saitta argues, results in a lot of false negatives: since the samples are small, it takes an extreme amount of variation between the sexes to trigger a positive test result. (Significance testing isn't just a consideration for paleontologists -- concerns over a "replication crisis" have plagued researchers in psychology and medicine, where certain studies are difficult to reproduce.)

Instead, Saitta and his colleagues experimented with another form of stats, called effect size statistics. Effect size statistics is better for smaller datasets because it attempts to estimate the degree of sex differences and calculate the uncertainty in that estimate. This alternative statistical method takes natural variations into account without viewing dimorphism as black-or-white-many sexual dimorphisms can be subtle. Co-author Max Stockdale of the University of Bristol wrote the code to run the statistical simulations. Saitta and his colleagues uploaded measurements of dinosaur fossils to the program, and it yielded estimates of body mass dimorphism and error bars in those estimates that would have simply been dismissed using significance testing.

"We showed that if you adopt this paradigm shift in statistics, where you attempt to estimate the magnitude of an effect and then put error bars around that, you can often produce a fairly accurate estimate of sexual variation even when the sexes of the individuals are unknown," says Saitta.

For instance, Saitta and his colleagues found that in the dinosaur Maiasaura, adult specimens vary a lot in size, and the analyses show that these are likelier to correspond to sexual variation than differences seen in other dinosaur species. But while the current data suggest that one sex was about 45% bigger than the other, they can't tell if the bigger ones are males or females.

While there's a lot of work yet to be done, Saitta says he's excited that the statistical simulations gave such consistent results despite the limits of the fossil data.

"Sexual selection is such an important driver of evolution, and to limit ourselves to ineffective statistical approaches hurts our ability to understand the paleobiology of these animals," he says. "We need to account for sexual variation in the fossil record."

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Lack of insects in cities limits breeding success of urban birds

Urban insect populations would need to increase by a factor of at least 2.5 for urban great tits to have same breeding success as those living in forests according to research published in the British Ecological Society's Journal of Animal Ecology.

Researchers at the University of Pannonia, Hungary and the University of Sheffield, UK found that providing high quality supplementary food to urban great tits, in the form of nutritionally enriched mealworms, can dramatically boost their breeding success.

"Urban nestlings had considerably higher survival chance and gained an extra two grams of body mass when provided with an insect-rich diet, an increase of 15% compared to the weight of chicks that didn't receive extra food. This is a substantial difference." said Dr Gábor Seress, lead author of the research. "This greater body mass when leaving the nest may increase the chicks' chance of surviving to spring and breeding themselves."

These beneficial effects of food supplementation were not seen in forest dwelling great tits where high quality nestling food is abundant. Although the free meals were also readily received by forest parents.

Reduced breeding success in urban bird populations is well documented but this study is the first to show that insect-rich supplementary food during nestling development largely mitigates these habitat differences. The findings indicate that food limitation in urban environments plays a crucial role in reducing the breeding success of insect-eating birds.

Dr Seress said: "Given the popularity of year-round bird feeding and the abundance of anthropogenic food sources in cities it might seem unlikely that urban birds have limited food. But quantity is not quality. Most songbirds require an insect-rich diet to successfully raise many and vigorous young, and urban areas generally support fewer insects than more natural habitats, especially caterpillars, which are key components of the optimal nestling diet for many species."

The authors say that artificially providing insect-rich food for birds in cities may not be the best solution. "Instead of directly supplying high-quality bird food to enhance urban birds' breeding success, we believe that management activities that aim to increase the abundance of insects in the birds' environment, would be more effective. Insects are the cornerstone of healthy and complex ecosystems and it is clear that we need more in our cities." said Dr Seress.

Increasing insect populations in cities in no easy task. The authors highlight that most urban green spaces are often highly managed which can reduce insect abundance. Modifying how green spaces are managed and encouraging practices like planting trees is likely to benefit both insect-eating birds as well as people.

In the experiment, the researchers studied great tits in nest boxes at urban and forest sites in Hungary, 2017. The urban sites were in the city of Veszprém with nest boxes placed in public green spaces such as parks and cemeteries. The forest site was three kilometres outside of Veszprém in deciduous woodland. At both sites there were broods that did not receive supplementary food to act as controls.

For the supplementary fed broods, the researchers provided nutritionally enhanced mealworms throughout brood rearing period on a daily basis, adjusting the amount in accordance to the brood size to meet 40-50% of food requirements. When nestlings were 15 days old (a few days from leaving the nest) the researchers recorded the size, weight and survival rate of chicks.

To estimate the amount of supplementary food consumed by the chicks and their parents, the researchers mounted small, hidden cameras on the nest boxes.

While the findings demonstrate that providing high quality additional food can boost breeding success, it is unclear to what extent this could increase population size and stability, further work is needed to explore this.

Read more at Science Daily

Virgin birth has scientists buzzing

In a study published today in Current Biology, researchers from University of Sydney have identified the single gene that determines how Cape honey bees reproduce without ever having sex. One gene, GB45239 on chromosome 11, is responsible for virgin births.

"It is extremely exciting," said Professor Benjamin Oldroyd in the School of Life and Environmental Sciences. "Scientists have been looking for this gene for the last 30 years. Now that we know it's on chromosome 11, we have solved a mystery."

Behavioural geneticist Professor Oldroyd said: "Sex is a weird way to reproduce and yet it is the most common form of reproduction for animals and plants on the planet. It's a major biological mystery why there is so much sex going on and it doesn't make evolutionary sense. Asexuality is a much more efficient way to reproduce, and every now and then we see a species revert to it."

In the Cape honey bee, found in South Africa, the gene has allowed worker bees to lay eggs that only produce females instead of the normal males that other honey bees do. "Males are mostly useless," Professor Oldroyd said. "But Cape workers can become genetically reincarnated as a female queen and that prospect changes everything."

But it also causes problems. "Instead of being a cooperative society, Cape honey bee colonies are riven with conflict because any worker can be genetically reincarnated as the next queen. When a colony loses its queen the workers fight and compete to be the mother of the next queen," Professor Oldroyd said.

The ability to produce daughters asexually, known as "thelytokous parthenogenesis," is restricted to a single subspecies inhabiting the Cape region of South Africa, the Cape honey bee or Apis mellifera capensis.

Several other traits distinguish the Cape honey bee from other honey bee subspecies. In particular, the ovaries of worker bees are larger and more readily activated and they are able to produce queen pheromones, allowing them to assert reproductive dominance in a colony.

These traits also lead to a propensity for social parasitism, a behaviour where Cape bee workers invade foreign colonies, reproduce and persuade the host colony workers to feed their larvae. Every year in South Africa, 10,000 colonies of commercial beehives die because of the social parasite behaviour in Cape honey bees.

"This is a bee we must keep out of Australia," Professor Oldroyd said.

The existence of Cape bees with these characters has been known for over a hundred years, but it is only recently, using modern genomic tools, that we have been able to understand the actual gene that gives rise to virgin birth.

"Further study of Cape bees could give us insight into two major evolutionary transitions: the origin of sex and the origin of animal societies," Professor Oldroyd said.

Read more at Science Daily

Synchrotron X-ray sheds light on some of the world's oldest dinosaur eggs

Dinosaur egg concept

An international team of scientists led by the University of the Witwatersrand in South Africa, has been able to reconstruct, in the smallest details, the skulls of some of the world's oldest known dinosaur embryos in 3D, using powerful and non-destructive synchrotron techniques at the ESRF, the European Synchrotron in France. They found that the skulls develop in the same order as those of today's crocodiles, chickens, turtles and lizards. The findings are published today in Scientific Reports.

University of the Witwatersrand scientists publish 3D reconstructions of the ~2cm-long skulls of some of the world's oldest dinosaur embryos in an article in Scientific Reports. The embryos, found in 1976 in Golden Gate Highlands National Park (Free State Province, South Africa) belong to South Africa's iconic dinosaur Massospondylus carinatus, a 5-meter long herbivore that nested in the Free State region 200 million years ago.

The scientific usefulness of the embryos was previously limited by their extremely fragile nature and tiny size. In 2015, scientists Kimi Chapelle and Jonah Choiniere, from the University of Witwatersrand, brought them to the European Synchrotron (ESRF) in Grenoble, France for scanning. At the ESRF, an 844 metre-ring of electrons travelling at the speed of light emits high-powered X-ray beams that can be used to non-destructively scan matter, including fossils. The embryos were scanned at an unprecedented level of detail -- at the resolution of an individual bone cell. With these data in hand, and after nearly 3 years of data processing at Wits' laboratory, the team was able to reconstruct a 3D model of the baby dinosaur skull. "No lab CT scanner in the world can generate these kinds of data," said Vincent Fernandez, one of the co-authors and scientist at the Natural History Museum in London (UK). "Only with a huge facility like the ESRF can we unlock the hidden potential of our most exciting fossils. This research is a great example of a global collaboration between Europe and the South African National Research Foundation," he adds.

Up until now, it was believed that the embryos in those eggs had died just before hatching. However, during the study, lead author Chapelle noticed similarities with the developing embryos of living dinosaur relatives (crocodiles, chickens, turtles, and lizards). By comparing which bones of the skull were present at different stages of their embryonic development, Chapelle and co-authors can now show that the Massospondylus embryos were actually much younger than previously thought and were only at 60% through their incubation period.

The team also found that each embryo had two types of teeth preserved in its developing jaws. One set was made up of very simple triangular teeth that would have been resorbed or shed before hatching, just like geckos and crocodiles today. The second set were very similar to those of adults, and would be the ones that the embryos hatched with. "I was really surprised to find that these embryos not only had teeth, but had two types of teeth. The teeth are so tiny; they range from 0.4 to 0.7mm wide. That's smaller than the tip of a toothpick!," explains Chapelle.

The conclusion of this research is that dinosaurs developed in the egg just like their reptilian relatives, whose embryonic developmental pattern hasn't changed in 200 million years. "It's incredible that in more than 250 million years of reptile evolution, the way the skull develops in the egg remains more or less the same. Goes to show -- you don't mess with a good thing!," concludes Jonah Choiniere, professor at the University of Witwatersrand and also co-author of the study.

Read more at Science Daily

Pablo Escobar's hippos may help counteract a legacy of extinctions

When cocaine kingpin Pablo Escobar was shot dead in 1993, the four hippos he brought to his private zoo in Colombia were left behind in a pond on his ranch. Since then, their numbers have grown to an estimated 80-100, and the giant herbivores have made their way into the country's rivers. Scientists and the public alike have viewed Escobar's hippos as invasive pests that by no rights should run wild on the South American continent.

A new study published in Proceedings of the National Academy of Sciences by an international group of researchers challenges this view. Through a worldwide analysis comparing the ecological traits of introduced herbivores like Escobar's hippos to those of the past, they reveal that such introductions restore many important traits that have been lost for thousands of years. While human impacts have caused the extinction of several large mammals over the last 100,000 years, humans have since introduced numerous species, inadvertently rewilding many parts of the world such as South America, where giant llamas once roamed, and North America, where the flat-headed peccary could once be found from New York to California.

"While we found that some introduced herbivores are perfect ecological matches for extinct ones, in others cases the introduced species represents a mix of traits seen in extinct species," says study co-author John Rowan, Darwin Fellow in organismic and evolutionary biology at the University of Massachusetts Amherst. "For example, the feral hippos in South America are similar in diet and body size to extinct giant llamas, while a bizarre type of extinct mammal -- a notoungulate -- shares with hippos large size and semiaquatic habitats. So, while hippos don't perfectly replace any one extinct species, they restore parts of important ecologies across several species."

Rowan was part of an international team of conservation biologists and ecologists from The University of Technology Sydney (UTS) in Australia, the University of Kansas and the University of California Davis and the Natural History Museum of Los Angeles County in the U.S., the University of Sussex in the U.K., the Universidad de Alcalá in Spain and Aarhus University in Denmark.

The authors note that what most conservation biologists and ecologists think of as the modern 'natural' world is very different than it was for the last 45 million years. Even recently, rhino-sized wombat-relatives called diprotodons, tank-like armored glyptodons and two-story tall sloths ruled the world. These giant herbivores began their evolutionary rise not long after the demise of the dinosaurs, but were abruptly driven extinct beginning around 100,000 years ago, most likely due to hunting and other pressures from our Late Pleistocene ancestors.

The researchers found that by introducing species across the world, humans restored lost ecological traits to many ecosystems; making the world more similar to the pre-extinction Late Pleistocene and counteracting a legacy of extinctions.

Erick Lundgren, lead author and Ph.D. student at the UTS Centre for Compassionate Conservation (CfCC), says the possibility that introduced herbivores might restore lost ecological functions had been suggested but not "rigorously evaluated."

To this end, the authors compared key ecological traits of herbivore species from before the Late Pleistocene extinctions to the present day, such as body size, diet and habitat.

"This allowed us to compare species that are not necessarily closely related to each other, but are similar in terms of how they affect ecosystems," Lundgren said. "By doing this, we could quantify the extent to which introduced species make the world more similar or dissimilar to the pre-extinction past. Amazingly they make the world more similar."

This is largely because 64% of introduced herbivores are more similar to extinct species than to local native species. These introduced 'surrogates' for extinct species include evolutionary close species in some places, like mustangs (wild horses) in North America, where pre-domestic horses of the same species lived but were driven extinct.

"Many people are concerned about feral horses and donkeys in the American southwest, because they aren't known from the continent in historic times," Rowan says. "But this view overlooks the fact that horses had been present in North America for over 50 million years -- all major milestones of their evolution, including their origin, takes place here. They only disappeared a few thousand years ago because of humans, meaning the North American ecosystems they have since been reintroduced to had coevolved with horses for millions of years."

"We usually think of nature as defined by the short period of time for which we have recorded history but this is already long after strong and pervasive human influences," said senior author Arian Wallach from UTS CfCC. "Broadening our perspective to include the more evolutionarily relevant past lets us ask more nuanced questions about introduced species and how they affect the world."

Read more at Science Daily

Ostrich eggshell beads reveal 10,000 years of cultural interaction across Africa

Ostrich eggshell beads are some of the oldest ornaments made by humankind, and they can be found dating back at least 50,000 years in Africa. Previous research in southern Africa has shown that the beads increase in size about 2,000 years ago, when herding populations first enter the region. In the current study, researchers Jennifer Miller and Elizabeth Sawchuk investigate this idea using increased data and evaluate the hypothesis in a new region where it has never before been tested.

Review of old ideas, analysis of old collections

To conduct their study, the researchers recorded the diameters of 1,200 ostrich eggshell beads unearthed from 30 sites in Africa dating to the last 10,000 years. Many of these bead measurements were taken from decades-old unstudied collections, and so are being reported here for the first time. This new data increases the published bead diameter measurements from less than 100 to over 1,000, and reveals new trends that oppose longstanding beliefs.

The ostrich eggshell beads reflect different responses to the introduction of herding between eastern and southern Africa. In southern Africa, new bead styles appear alongside signs of herding, but do not replace the existing forager bead traditions. On the other hand, beads from the eastern Africa sites showed no change in style with the introduction of herding. Although eastern African bead sizes are consistently larger than those from southern Africa, the larger southern African herder beads fall within the eastern African forager size range, hinting at contact between these regions as herding spread. "These beads are symbols that were made by hunter-gatherers from both regions for more than 40,000 years," says lead author Jennifer Miller, "so changes -- or lack thereof -- in these symbols tells us how these communities responded to cultural contact and economic change."

Ostrich eggshell beads tell the story of ancient interaction

The story told by ostrich eggshell beads is more nuanced than previously believed. Contact with outside groups of herders likely introduced new bead styles along with domesticated animals, but the archaeological record suggests the incoming influence did not overwhelm existing local traditions. The existing customs were not replaced with new ones; rather they continued and incorporated some of the new elements.

In eastern Africa, studied here for the first time, there was no apparent change in bead style with the arrival of herding groups from the north. This may be because local foragers adopted herding while retaining their bead-making traditions, because migrant herders possessed similar traditions prior to contact, and/or because incoming herders adopted local styles. "In the modern world, migration, cultural contact, and economic change often create tension," says Sawchuk, "ancient peoples experienced these situations too, and the patterns in cultural objects like ostrich eggshell beads give us a chance to study how they navigated these experiences."

The researchers hope that this work inspires a renewed interest into ostrich eggshell beads, and recommend that future studies present individual bead diameters rather than a single average of many. Future research should also investigate questions related to manufacture, chemical identification, and the effects of taphonomic processes and wear on bead diameter. "This study shows that examining old collections can generate important findings without new excavation," says Miller, "and we hope that future studies will take advantage of the wealth of artifacts that have been excavated but not yet studied."

From Science Daily

Bonobo mothers help their sons to have more offspring

Bonobos.

In many social animal species individuals share child-rearing duties, but new research from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, finds that bonobo mothers go the extra step and actually take action to ensure their sons will become fathers. This way bonobo mothers increase their sons' chance of fatherhood three-fold.

"This is the first time that we can show the impact of the mother's presence on a very important male fitness trait, which is their fertility," says Martin Surbeck, a primatologist at the Max Planck Institute for Evolutionary Anthropology. "We were surprised to see that the mothers have such a strong, direct influence on the number of grandchildren they get."

Surbeck and his colleagues observed wild populations of bonobos in the Democratic Republic of Congo, as well as wild populations of chimpanzees in Ivory Coast, Tanzania, and Uganda. They found that while both bonobo and chimpanzee mothers would advocate for their sons in male-on-male conflicts, bonobo moms went the extra mile to aid their sons' copulation efforts. This involved protecting their sons' mating attempts from other males and intervening in other male's mating attempts.

The bonobo mothers were also able to use their rank in the bonobo's matriarchal society to give their sons access to popular spots within social groups in the community and help them achieve higher male status -- and therefore, better mating opportunities. The authors note that these interactions were rare in chimpanzee societies and did not have an effect on male fertility; in chimpanzees males hold dominant positions over females, making the actions of chimp mothers less influential than those of bonobo mothers.

Interestingly, bonobo moms did not extend similar help to their daughters, nor were there any observations of daughters receiving assistance in rearing their offspring. "In bonobo social systems, the daughters disperse from the native community and the sons stay," Surbeck says. "And for the few daughters that stay in the community, which we don't have many examples of, we don't see them receiving much help from their mothers."

Moving forward, Surbeck and his team would like to better understand the benefits these behaviors confer on bonobo mothers. Currently, they think that it allows for an indirect continuation of their genes. "These females have found a way to increase their reproductive success without having more offspring themselves," he says, noting that the prolongation of the post-reproductive human female lifespan, as well as the early-age at which human women can no longer bare children, may have evolved from this indirect method of continuing their genetic line.

Surbeck acknowledges that gathering data on post-reproductive lifespans of females in chimp and bonobo communities will require a long-term, collaborative study, similar to this one. "Without the help and participation from all of the field sites where data was collected, these important interactions could have been overlooked," he says. "Now as the director of a bonobo field site, I'm looking forward to further exploring this topic."

Read more at Science Daily

Scientists propose rethinking 'endangered species' definition to save slow-breeding giants

Elephants.

Conservation decisions based on population counts may fail to protect large, slow-breeding animals from irrevocable decline, according to new research coinciding with Endangered Species Day.

"Critical thresholds in so-called vital rates -- such as mortality and fertility rates among males and females of various ages -- can signal an approaching population collapse long before numbers drop below a point of no return," says lead author Dr. Shermin de Silva, President & Founder of Asian elephant conservation charity Trunks & Leaves. "We propose that conservation efforts for Asian elephants and other slow-breeding megafauna be aimed at maintaining their 'demographic safe space': that is, the combination of key vital rates that supports a non-negative growth rate."

A mammoth insight

Published in Frontiers in Ecology and Evolution, the study suggests that a combination of key vital rates governing population growth is a better indicator of a species' viability than short-term trends in population size and distribution.

"History bears this out," argues de Silva. "Genomic studies of the last mammoths isolated on Wrangel Island -- between Russia and Alaska -- have shown that although they were able to persist for thousands of years beyond the extinction of mainland populations with just ~300 individuals, they had accumulated numerous genetic mutations that may have eventually contributed to their extinction."

In other words populations of megafauna can become biologically inviable long before they disappear, if pushed beyond their 'demographic safe space.'

Females and calves key to saving the Asian elephant

The group applied the 'demographic safe space' concept to the case of the Asian elephant.

"Asian elephants are classified as 'Endangered' under the IUCN Red List because populations are thought to have declined by at least 50% in less than a century," explains de Silva. "There are fewer than 50,000 wild Asian elephants living today."

Studies show that wild Asian elephants breed extremely slowly, the majority producing just one calf in six years or more. Using mathematical modeling, de Silva and colleagues found that near-optimal reproduction and high calf survival is necessary to maintain non-negative population growth in the face of even modestly increased mortality among adult female age classes.

The approach shows a clear conservation priority for Asian elephants, a species in which the vast majority is tuskless.

"Measures to enhance survival of calves, and particularly females, are key to saving the Asian elephant," emphasizes de Silva.

"But while the attention of the world has been focused on the ivory trade, for critically endangered Asian elephant populations the greatest threat is habitat loss -- followed by illegal trade in live animals and parts.

"Habitat loss can create something known as 'extinction debt' by slowing down birth rates and increasing mortality rates. For slow breeding long-lived species, even incremental changes make a big difference, but their longevity can obscure the risk of extinction."

A demographic safe space for all megafauna

Conservation efforts for other large, slow-breeding species -- such as giraffes, rhinos, Bactrian camels and eastern gorillas -- could also benefit from modelling the interaction between vital rates. Data for these species in the wild are a scarce yet urgent necessity, suggest the authors.

"Rather than rely on simple population counts or estimates of near-term extinction probability, we urge that conservation resources for slow-breeding megafauna also be invested in identifying demographic tipping points and how to maintain populations within their safe spaces.

Read more at Science Daily

Chewing versus sex in duck-billed dinosaurs

The skulls of three hadrosaur dinosaurs, Lambeosaurus lambei (top left), Gryposaurus notabilis (top right), Parasaurolophus walkeri (lower).

The duck-billed hadrosaurs walked the Earth over 90-million years ago and were one of the most successful groups of dinosaurs. But why were these 2-3 tonne giants so successful? A new study, published in Paleobiology, shows that their special adaptations in teeth and jaws and in their head crests were crucial, and provides new insights into how these innovations evolved.

Called the 'sheep of the Mesozoic'as they filled the landscape in the Late Cretaceous period, hadrosaurs walked on their hind legs and were known for their powerful jaws with multiple rows of extremely effective teeth. They also had hugely varied head display crests that signalled which species each belonged to and were used to attract mates. Some even trumpeted and tooted their special call, using nasal passages through the head crests.

Researchers from the Universities of Bristol and the Catalan Institute of Paleontology in Barcelona used a large database describing morphological variety in hadrosaur fossils and computational methods that quantify morphological variety and the pace of evolution.

Dr Tom Stubbs, lead author of the study and a researcher from Bristol's School of Earth Sciences, said: "Our study shows that the unique hadrosaur feeding apparatus evolved fast in a single burst, and once established, showed very little change. In comparison, the elaborate display crests kept diversifying in several bursts of evolution, giving rise to the many weird and wonderful shapes."

Professor Mike Benton, the study's co-author from Bristol's School of Earth Sciences, added, "Variation in anatomy can arise in many ways. We wanted to compare the two famous hadrosaur innovations, and by doing so, provide new insights into the evolution of this important dinosaur group. New numerical methods allow us to test these kinds of complex evolutionary hypotheses."

"Our methods allowed us to identify branches on the hadrosaur evolutionary tree that showed rapid evolution in different parts of the skeleton," said co-author Dr Armin Elsler. "When we looked at the jaws and teeth, we only saw fast evolution on a single branch at the base of the group. On the other hand, the bones that form the display crests showed multiple fast rate branches."

Dr Albert Prieto-Márquez, co-author and world-leading expert on hadrosaurs from the Catalan Institute of Paleontology in Barcelona, added: "Our results suggest that evolution can be driven in different ways by natural selection and sexual selection. Hadrosaurs apparently fixed on a feeding apparatus that was successful and did not require massive modification to process their food. On the other hand, sexual selection drove the evolution of more complex crest shapes, and this is reflected by multiple evolutionary bursts."

From Science Daily

Climate change is a threat to dolphins' survival

This is a dolphin mother and calf in Shark Bay.

An unprecedented marine heatwave had long-lasting negative impacts on both survival and birth rates on the iconic dolphin population in Shark Bay, Western Australia. Researchers at UZH have now documented that climate change may have more far-reaching consequences for the conservation of marine mammals than previously thought.

Shark Bay in Western Australia in early 2011: A heatwave causes the water temperatures to rise to more than four degrees above the annual average. The extended period caused a substantial loss of seagrass, which drives the Shark Bay ecosystem, in this coastal area, a UNESCO world heritage site.

Researchers from UZH have now investigated how this environmental damage has affected survival and reproduction of dolphins. They used long-term data on hundreds of animals collected over a ten-year period from 2007 to 2017. Their analyses revealed that the dolphins' survival rate had fallen by 12 percent following the heatwave of 2011. Moreover, female dolphins were giving birth to fewer calves -- a phenomenon that lasted at least until 2017.

Negative influence of the heatwave is unprecedented

"The extent of the negative influence of the heatwave surprised us," says Sonja Wild, former PhD candidate at the University of Leeds and first author of the study. "It is particularly unusual that the reproductive success of females appears to have not returned to normal levels, even after six years." There are several possible explanations for this phenomenon, for instance neglect of calves, increased newborn mortality, delayed sexual maturity or a combination thereof, but researchers have not yet been able to investigate them in detail.

Tool-using dolphins are less affected

Interestingly, the heatwave did not have the same effect on all dolphin groups. Dolphins that use sponges as tools -- a socially learned foraging technique that helps dolphins to locate food in deep water -- were not as badly affected as those that do not use this technique. "Nevertheless, our work raises concerns that such sudden events might have quite negative long-term effects even in groups of marine mammals that are known to adapt usually well to novel environmental conditions," says Sonja Wild.

Read more at Science Daily

World's oldest semen still viable

'Sir Freddie,' one of the original semen donors, in 1969.

Semen stored since 1968 in a laboratory in Sydney has been defrosted and successfully used to impregnate 34 Merino ewes, with the resulting live birth rate as high sperm frozen for just 12 months.

"This demonstrates the clear viability of long-term frozen storage of semen. The results show that fertility is maintained despite 50 years of frozen storage in liquid nitrogen," said Associate Professor Simon de Graaf from the Sydney Institute of Agriculture and School of Life and Environmental Sciences at the University of Sydney.

"The lambs appear to display the body wrinkle that was common in Merinos in the middle of last century, a feature originally selected to maximise skin surface area and wool yields. That style of Merino has since largely fallen from favour as the folds led to difficulties in shearing and increased risk of fly strike," Associate Professor de Graaf said.

His colleague on this project, Dr Jessica Rickard, said: "We believe this is the oldest viable stored semen of any species in the world and definitely the oldest sperm used to produce offspring."

Associate Professor de Graaf said that it was the reproductive biology and genetic aspects of these as-yet unpublished findings that were of most interest to him.

"We can now look at the genetic progress made by the wool industry over past 50 years of selective breeding. In that time, we've been trying to make better, more productive sheep," he said. "This gives us a resource to benchmark and compare."

Dr Rickard is a post-doctoral McCaughey Research Fellow in the Sydney Institute of Agriculture. She is continuing the strong animal reproduction research tradition in veterinary and biological sciences at the University of Sydney through her work in the Animal Reproduction Group.

Dr Rickard did the original work to determine if the stored semen was viable for artificial insemination. This involved thawing the semen, which is stored as small pellets in large vats of liquid nitrogen at -196 degrees. She and her colleagues then undertook in vitro tests on the sperm quality to determine the motility, velocity, viability and DNA integrity of the 50-year-old sperm.

"What is amazing about this result is we found no difference between sperm frozen for 50 years and sperm frozen for a year," Dr Rickard said.

Out of 56 ewes inseminated, 34 were successfully impregnated. This compares to recently frozen semen from 19 sires used to inseminate 1048 ewes, of which 618 were successfully impregnated. This gives a pregnancy rate of 61 percent for the 50-year-old semen against 59 percent for recently frozen sperm, a statistically equivalent rate.

The original semen samples were donated in the 1960s from sires owned by the Walker family. Those samples, frozen in 1968 by Dr Steven Salamon, came from four rams, including 'Sir Freddie' born in 1963, owned by the Walkers on their then property at Ledgworth.

Read more at Science Daily

Bacteria may help frogs attract mates

Adult female (left) and calling male of Boana prasina.

Brazilian scientists have discovered that the strong odor released by some amphibian species is produced by bacteria and that attracting a mate is one of its purposes. The bacteria in question are a noteworthy example of symbiosis as they assist in the animal's mating process. A paper recounting the discovery of this role of microorganisms isolated from the skin of frogs has been published in the journal Proceedings of the National Academy of Sciences (PNAS).

"Frogs emit a pungent odor. Sometimes a particular species can be recognized by its scent, but until now, the function of this odor was unknown. It was typically assumed to be an aposematic smell, meaning a chemical warning sign that served to repel predators, as in the case of skunks [Mephitis mephitis] among mammals, for example," said Célio Haddad, a professor at São Paulo State University's Rio Claro Bioscience Institute (IBRC-UNESP) in Brazil and a coauthor of the article.

According to Haddad, who is also affiliated with the university's Aquaculture Center (CAUNESP) in Jaboticabal, this hypothesis was considered plausible because many amphibian species, especially when poisonous, are brightly colored, and this serves as a visual alert to frighten predators. "We thought odor might play a similar role among anurans [frogs and toads]," he said.

The new study resulted from the postdoctoral research of Argentinean biologist Andrés Eduardo Brunetti, supervised by Professor Norberto Peporine Lopes. Conducted at the University of São Paulo's Ribeirão Preto School of Pharmaceutical Sciences (FCFRP-USP), the research was supported by FAPESP.

"The importance and originality of Brunetti's research is that for the first time it shows a pronounced difference in the odors emitted by frogs of opposite sexes," Haddad said. "No other studies of anurans have ever described this type of behavior. The results suggest that the odor serves to permit mutual recognition between males and females of the same species for mating purposes."

The research was also supported by the FAPESP Research Program on Biodiversity Characterization, Conservation, Restoration and Sustainable Use (BIOTA-FAPESP) and by the University of São Paulo (USP), the National Council for Scientific and Technological Development (CNPq) and Brazil's Coordination for the Improvement of Higher Education Personnel (CAPES).

"In anurans, you often see different species sharing a lake or marsh. In such places, there are 30 male frogs for every female of the same species on average. The question is how the females recognize males of their own species among a multitude of males belonging to several species while they're all vocalizing at the same time," Brunetti said.

"It's well-known that the function of the call of anuran males is to attract females and that every species has a characteristic song. Our findings suggest that odor appears to play a similar role, serving as an olfactory signal that enables females to recognize males of their own species."

Biologists were also unaware of a difference in the scents of male and female frogs. Brunetti discovered this difference during his research, whose primary goal was to understand the chemical composition of the volatile components emitted by the skin of various frog species.

His working hypothesis suggested that smell was a chemical warning sign that served to repel predators. To verify the hypothesis, Brunetti conducted field surveys at several sites in São Paulo state and Rio de Janeiro state, collecting specimens of the tree frog Boana prasina.

"It's very hard to collect females in the wild. Initially, we managed to collect only males. When we noticed what appeared to be a sexual difference in their odors, I went into the field again with the specific aim of capturing females for comparison," he said.

"During my doctoral research at the Argentinian Natural Science Museum in Buenos Aires, while investigating the volatile compounds in two other frog species, I discovered that the secretions were made up of a blend of 35 to 42 compounds in nine different chemical classes. We then realized that some of the compounds had the specific signature of compounds produced by bacteria."

Brunetti came to Brazil to investigate whether the selected tree frogs had skin bacteria that produced the characteristic odor of each species, and if so, which compounds they produced. His laboratory research proceeded on two fronts: analysis of the volatile compounds released by the skin of these frogs and identification of the bacteria on their skin.

Brunetti and colleagues used gas chromatography and mass spectrometry to analyze the diversity of the volatile components secreted by the skin of B. prasina. They found that adult males and females secrete a blend of 60-80 compounds, including alcohols, aldehydes, alkenes, ethers, ketones, methoxypyrazines, terpenes and thioethers.

The compounds were exactly the same in both males and females, but the researchers were surprised to find a pronounced sexual difference in the levels of methoxypyrazines, terpenes, and thioethers.

"These three components were responsible for the difference between males and females. Thioethers and methoxypyrazines are typically produced by microorganisms," Brunetti said.

They decided to determine whether microorganisms were the source of these compounds in B. prasina. To do so, they isolated, cultivated and identified bacteria associated with the skin of these frogs and analyzed their volatile components.

No fewer than 128 different components were detected. Analysis of each component revealed that four methoxypyrazines present in males and females were produced by a single bacterium of the genus Pseudomonas.

In B. prasina, Brunetti discovered, methoxypyrazines were much more abundant in females than in males. Two of the four types of methoxypyrazines were measured at higher levels in females, while two were found at higher levels in males.

Symbiotic relationship

"The interesting thing about Pseudomonas sp. is that these bacteria live on the skin of males and females, where they metabolize the same volatile compounds but at different levels of concentration according to the sex of the host," Brunetti said.

The levels of methoxypyrazine measured in these frogs, he added, suggest the existence of a complex mechanism of metabolic interactions that creates a different environment on the skin of males and females, favoring the synthesis of characteristic methoxypyrazines in each sex.

"These frogs and bacteria have a symbiotic relationship. In exchange for the service provided by the bacteria, entailing sexual differentiation by scent, the frogs provide an environment -- their own skin -- on which the bacteria can proliferate," he explained.

The function of this sexual difference in methoxypyrazine levels is unknown. "However, we assume that the difference in scent helps male frogs of this species recognize females of the same species in places inhabited by other frog species," Brunetti said.

"We know that many anurans use visual communication [bright skin colors] to repel predators as well as acoustic communication [vocalization] to attract female mates. Perhaps B. prasina uses a form of olfactory communication for the same purpose."

Brunetti will attempt to confirm this hypothesis in future research. If correct, it will have major repercussions. "Only one anuran, in Madagascar, is currently known to communicate by odor. Among amphibians, salamanders, which are distant relatives of anurans, are known to use this form of communication," Haddad said.

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Earliest example of animal nest sharing revealed by scientists

Two of the fossilized enantiornithine eggs.

An international team of scientists, including researchers from the University of Southampton, has shown that fossilised eggshells unearthed in western Romania represent the earliest known nest site shared by multiple animals.

The shells -- some complete and others broken into thousands of pieces -- are densely packed and encased in mudstone which formed part of the remains of a bird breeding colony, probably comprising hundreds of seperate nests.

Now in the collections of the Transylvanian Museum Society in Cluj Napoca, Romania, the samples date from the late-Cretaceous period (approx. 70 million years ago) and were discovered near the city of Sebeş in Transylvania by local palaeontologist Mátyás Vremir about nine years ago.

Led by Centro Regional Universitario Bariloche in Argentina, the scientists examined sophisticated electron microscope images of the unique, fossilised material from the site. They established it contains four different types of egg shell, indicating that four types of animals all shared the same nesting site; extinct birds within a group known as enantiornithes, birds of undetermined classification, gecko-like lizards and smaller predecessors of today's crocodiles.

Christian Laurent, Tizard Scholar and member of the Aerodynamics and Flight Mechanics Group at the University of Southampton, comments: "We know very little about the parental behaviour of Mesozic birds, We know they had nests, laid eggs and hatched young which were relatively mature and able to move around after hatching -- but evidence is scant beyond this. This research suggests they were tolerant of creating their nests, not only alongside other birds, but also reptiles."

The team, which also includes researchers from the University of Jinan (China), the Transylvanian Museum Society (Romania), the Royal British Columbia Museum (Canada), the University of Debrecen (Hungary), and Pavol Jozef Safarik University (Slovak Republic), has published its findings in the journal Nature Scientific Reports.

Their paper speculates that an area of plain created by seasonal flooding offered the enantiornithes safety from predators. It's also believed that their nest environments afforded shelter to smaller reptiles which benefitted from the security of the birds guarding their own nests. The researchers suggest that the lizard and crocodile type animals were not perceived as a threat to the bird eggs and nestlings -- possibly because they were much smaller than the adult birds and so not a predatory threat to them or their hatchlings. To date, this is the oldest example of this kind of ecological strategy.

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