Agricultural impact of flooding

I can barely hear Esther Ngumbi over the roar of greenhouse fans as she shows me around her rooftop laboratory in Morrill Hall. The benches are full of tomato plants, and the tomatoes don't look good. Half of the plants are submerged in bins of water. Their leaves are yellow and withering. Some of the dying tomatoes have flowered. I see one or two baby tomatoes on a couple of spindly plants.

This isn't the only torture inflicted on the tomatoes. Someone has tied little baggies to their stems. Inside the bags, fat green caterpillars are chowing down on the tomato leaves.

Entomology professor Ngumbi has questions -- lots of them -- and this is how she's set out to answer some of them. She is purposely flooding the tomatoes to see how they might respond to flooded conditions in farmers' fields -- a scenario that is becoming more common as a result of climate change.

"In nature, there are many stressors on plants during flooding," Ngumbi says. "Once the tomatoes get flooded, they're already weak, so most likely they will be attracting insects, which like to eat weaker plants. We're investigating how the plants deal with the combined stress of flooding and herbivory."

This explains the caterpillars. They are the larval form of Manduca sexta, the tobacco hornworm. They are feasting on one of the two heirloom tomato varieties Ngumbi is using in the experiment: Cherokee purple and striped German.

Half of the tomato plants in the greenhouse are not flooded, allowing the team to compare the stressed plants with those grown in more common conditions. But there are more investigations going on here.

"Also, within this experiment, we're looking at the microbes," Ngumbi says. "We want to understand how the microbial community changes in flooded conditions."

One of Ngumbi's key focuses is how soil microbes influence plant health and productivity. She's fascinated by mycorrhizal fungi, which form intimate associations with plant roots, offering essential elements like nitrogen to the plants in exchange for glucose supplied by the roots.

The tomato plants are all growing in soil from an Illinois farm, but half were also inoculated with mulch from a local farmer who has developed his own recipe for nurturing mycorrhizal fungi in the soil. Ngumbi wants to see if this inoculation makes any difference to the plants' ability to defend themselves from the fat caterpillars.

To measure plant defenses, Ngumbi's team collects samples of gases emitted by the plants and screens them for volatile organic compounds, the chemicals plants use to ward off bugs that would eat them.

Two years later, Ngumbi publishes the results of these and other laboratory experiments. She found that the two tomato varieties differed in gene expression and in the volatile compounds they emitted -- before any intervention. And when flooded, both varieties of tomatoes had very different chemical emission profiles than when grown in normal conditions. Herbivory influenced the production of these volatile compounds, but not as much as flooding did.

Today, the experiments continue, and Ngumbi's interest in the effects of flooding has only intensified. In a new review published in the journal Trends in Plant Research, she spells out the many changes that occur when plants are inundated with water for days or weeks at a time.

"Flooding is different from other climate-related stressors because it deprives plants of oxygen, an essential and indispensable element and substrate for plant growth and development," Ngumbi writes. Flooding disrupts plant metabolism and energy generation. It interferes with photosynthesis. Flooding kills beneficial bacteria and promotes pathogenic microbes in the soil. It also can compromise plants' ability to defend themselves from disease and harmful insects like the tobacco hornworm.

Ngumbi also warns that increased flooding can undermine decades of research aimed at making plants more resilient to climate change. Flooding may thwart efforts to build soil quality and microbial health to make crops more resilient to stressors such as heat and drought. Flooding also may eliminate gains derived from genetic engineering or plant breeding.

With flooding intensity and frequency predicted to increase by roughly 7% for every 1° C increase in global average temperatures, Ngumbi writes, scientists must consider the impacts of floods to "protect the monumental gains made in building climate-resilient crops."

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Backyard insect inspires invisibility devices, next gen tech

Leafhoppers, a common backyard insect, secrete and coat themselves in tiny mysterious particles that could provide both the inspiration and the instructions for next-generation technology, according to a new study led by Penn State researchers. In a first, the team precisely replicated the complex geometry of these particles, called brochosomes, and elucidated a better understanding of how they absorb both visible and ultraviolet light.

This could allow the development of bioinspired optical materials with possible applications ranging from invisible cloaking devices to coatings to more efficiently harvest solar energy, said Tak-Sing Wong, professor of mechanical engineering and biomedical engineering. Wong led the study, which was published today (March 18) in the Proceedings of the National Academy of Sciences of the United States of America (PNAS).

The unique, tiny particles have an unusual soccer ball-like geometry with cavities, and their exact purpose for the insects has been something of a mystery to scientists since the 1950s. In 2017, Wong led the Penn State research team that was the first to create a basic, synthetic version of brochosomes in an effort to better understand their function.

"This discovery could be very useful for technological innovation," said Lin Wang, postdoctoral scholar in mechanical engineering and the lead author of the study. "With a new strategy to regulate light reflection on a surface, we might be able to hide the thermal signatures of humans or machines. Perhaps someday people could develop a thermal invisibility cloak based on the tricks used by leafhoppers. Our work shows how understanding nature can help us develop modern technologies."

Wang went on to explain that even though scientists have known about brochosome particles for three-quarters of a century, making them in a lab has been a challenge due to the complexity of the particle's geometry.

"It has been unclear why the leafhoppers produce particles with such complex structures," Wang said, "We managed to make these brochosomes using a high-tech 3D-printing method in the lab. We found that these lab-made particles can reduce light reflection by up to 94%. This is a big discovery because it's the first time we've seen nature do something like this, where it controls light in such a specific way using hollow particles."

Theories on why leafhoppers coat themselves with a brochosome armor have ranged from keeping them free of contaminants and water to a superhero-like invisibility cloak. However, a new understanding of their geometry raises a strong possibility that its main purpose could be the cloak to avoid predators, according to Tak-Sing Wong, professor of mechanical engineering and biomedical engineering and corresponding author of the study.

The researchers have found that the size of the holes in the brochosome that give it a hollow, soccer ball-like appearance is extremely important. The size is consistent across leafhopper species, no matter the size of the insect's body. The brochosomes are roughly 600 nanometers in diameter -- about half the size of a single bacterium -- and the brochosome pores are around 200 nanometers.

"That makes us ask a question," Wong said. "Why this consistency? What is the secret of having brochosomes of about 600 nanometers with about 200-nanometer pores? Does that serve some purpose?"

The researchers found the unique design of brochosomes serves a dual purpose -- absorbing ultraviolet (UV) light, which reduces visibility to predators with UV vision, such as birds and reptiles, and scattering visible light, creating an anti-reflective shield against potential threats. The size of the holes is perfect for absorbing light at the ultraviolet frequency.

This potentially could lead to a variety of applications for humans using synthetic brochosomes, such as more efficient solar energy harvesting systems, coatings that protect pharmaceuticals from light-induced damage, advanced sunscreens for better skin protection against sun damage and even cloaking devices, researchers said. To test this, the team first had to make synthetic brochosomes, a major challenge in and of itself.

In their 2017 study, the researchers mimicked some features of brochosomes, particularly the dimples and their distribution, using synthetic materials. This allowed them to begin understanding the optical properties. However, they were only able to make something that looked like brochosomes, not an exact replica.

"This is the first time we are able to make the exact geometry of the natural brochosome," Wong said, explaining that the researchers were able to create scaled synthetic replicas of the brochosome structures by using advanced 3D-printing technology.

They printed a scaled-up version that was 20,000 nanometers in size, or roughly one-fifth the diameter of a human hair. The researchers precisely replicated the shape and morphology, as well as the number and placement of pores using 3D printing, to produce still-small faux brochosomes that were large enough to characterize optically.

They used a Micro-Fourier transform infrared (FTIR) spectrometer to examine how the brochosomes interacted with infrared light of different wavelengths, helping the researchers understand how the structures manipulate the light.

Next, the researchers said they plan to improve the synthetic brochosome fabrication to enable production at a scale closer to the size of natural brochosomes. They will also explore additional applications for synthetic brochosomes, such as information encryption, where brochosome-like structures could be used as part of an encryption system where data is only visible under certain light wavelengths.

Wang noted that their brochosome work demonstrates the value of a biomimetic research approach, where scientists looks to nature for inspiration.

"Nature has been a good teacher for scientists to develop novel advanced materials," Wang said. "In this study, we have just focused on one insect species, but there are many more amazing insects out there that are waiting for material scientists to study, and they may be able to help us solve various engineering problems. They are not just bugs; they are inspirations."

Read more at Science Daily

Mini-robots modeled on insects may be smallest, lightest, fastest ever developed

Two insect-like robots, a mini-bug and a water strider, developed at Washington State University, are the smallest, lightest and fastest fully functional micro-robots ever known to be created.

Such miniature robots could someday be used for work in areas such as artificial pollination, search and rescue, environmental monitoring, micro-fabrication or robotic-assisted surgery.

Reporting on their work in the proceedings of the IEEE Robotics and Automation Society's International Conference on Intelligent Robots and Systems, the mini-bug weighs in at eight milligrams while the water strider weighs 55 milligrams.

Both can move at about six millimeters a second.

"That is fast compared to other micro-robots at this scale although it still lags behind their biological relatives," said Conor Trygstad, a PhD student in the School of Mechanical and Materials Engineering and lead author on the work.

An ant typically weighs up to five milligrams and can move at almost a meter per second.

The key to the tiny robots is their tiny actuators that make the robots move.

Trygstad used a new fabrication technique to miniaturize the actuator down to less than a milligram, the smallest ever known to have been made.

"The actuators are the smallest and fastest ever developed for micro-robotics," said Néstor O. Pérez-Arancibia, Flaherty Associate Professor in Engineering at WSU's School of Mechanical and Materials Engineering who led the project.

The actuator uses a material called a shape memory alloy that is able to change shapes when it's heated.

It is called 'shape memory' because it remembers and then returns to its original shape.

Unlike a typical motor that would move a robot, these alloys don't have any moving parts or spinning components.

"They're very mechanically sound," said Trygstad. "The development of the very lightweight actuator opens up new realms in micro-robotics."

Shape memory alloys are not generally used for large-scale robotic movement because they are too slow.

In the case of the WSU robots, however, the actuators are made of two tiny shape memory alloy wires that are 1/1000 of an inch in diameter.

With a small amount of current, the wires can be heated up and cooled easily, allowing the robots to flap their fins or move their feet at up to 40 times per second.

In preliminary tests, the actuator was also able to lift more than 150 times its own weight.

Compared to other technologies used to make robots move, the SMA technology also requires only a very small amount of electricity or heat to make them move.

"The SMA system requires a lot less sophisticated systems to power them," said Trygstad.

Trygstad, an avid fly fisherman, has long observed water striders and would like to further study their movements.

While the WSU water strider robot does a flat flapping motion to move itself, the natural insect does a more efficient rowing motion with its legs, which is one of the reasons that the real thing can move much faster.

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Evolutionary chance made this bat a specialist hunter

Ask a biologist why predators don't exterminate all their prey, part of the answer often is that there is an ongoing arms race between predators and prey, with both parties continuously evolving new ways to cheat each other.

The hypothesis is particularly prevalent for bats and their prey; insects. 50 million years ago, the first bats evolved the ability to echolocate and thus hunt in the dark, and in response to this, some insects evolved ultrasound-sensitive ears so they could hear and evade the bats.

But if there is an ongoing arms race, bats should have responded to this, says University of Southern Denmark biologist, associate professor and bat expert Lasse Jakobsen, co-author of a new study published in Current Biology, In the study, he and colleagues question the evolutionary arms race between bats and insects.

The other authors are Daniel Lewanzik and Holger R. Goerlitz from the Max Planck Institute for Biological Intelligence and John M. Ratcliffe and Erik Etzler from the University of Toronto.

The main argument supporting the arms race hypothesis is that some bats do not call as loudly as others when hunting, and thus cannot be heard as easily by the insects. These are the barbastelles (Barbastella barbastellus), and they are approx. 20 dB quieter than other bats that hunt flying insects, which means that the sound pressure they emit is 10 times lower.

- The barbastelle is traditionally highlighted as the bat that has "struck back" at the insects, says Lasse Jakobsen.

But something puzzled him and his colleagues: If you look at the barbastelle's close relatives, there are virtually no other members catching insects in the air. Instead, they eat insects that sit on surfaces such as leaves and branches, and those species are all quieter than the species that hunt flying insects.

In bat research circles, the bats that catch insects in the air are called hawking bats, while the bats that pick insects from a surface, so to speak, are called gleaning bats. The barbastelle is a hawking bat.

- If most of the barbastelle's family are gleaners, then their ancestor was very likely also a gleaner, says Lasse Jakobsen.

Accordingly, it is therefore unlikely that the ancestor of the barbastelle was a loud hawker that evolved into the whispering barbastelle as a response to insect hearing.

- A species does not have free choice when it evolves in a new direction. For example, it is a condition for mammals that their ancestor did not have feathers, so their descendants will never evolve a wing with feathers. Instead, they have found another solution for flying: modified skin between the fingers, explains Lasse Jakobsen.

But if the barbastelle didn't evolve its ability to be quieter when hunting in the air, as part of the arms race between insects and bats; where does it come from?

- It is not an evolved ability. It just cannot produce louder calls than it does, because as a descendant of a gleaner it is probably morphologically limited. But it has found a niche, where it can use its low amplitude calls. It is an evolutionary coincidence; it sort of fell into this niche, where there was something to eat.

This niche is populated by flying, nocturnal insects that can hear and are thus good at avoiding nocturnal bats. But they cannot hear well enough to register the barbastelle, so they end up as their prey.

The reason for the morphological limitation must be found in how bats emit their sound. Most bats call out of their mouths, and this allows them to emit loud sounds. Many gleaners, on the other hand, emit sound with their noses, and this makes their calls 20 dB lower.

- So, the reason why the barbastelles are so quiet today is not an expression of an arms race between bats and insects, but rather simply an expression of the fact that it is descended from bats that cannot call as loudly as others, says Lasse Jakobsen.

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Fruit, nectar, bugs and blood: How bat teeth and jaws evolved for a diverse dinnertime

They don't know it, but Darwin's finches changed the world. These closely related species -- native to the Galapagos Islands -- each sport a uniquely shaped beak that matches their preferred diet. Studying these birds helped Charles Darwin develop the theory of evolution by natural selection.

A group of bats has a similar -- and more expansive -- evolutionary story to tell. There are more than 200 species of noctilionoid bats, mostly in the American tropics. And despite being close relatives, their jaws evolved in wildly divergent shapes and sizes to exploit different food sources. A paper published Aug. 22 in Nature Communications shows those adaptations include dramatic, but also consistent, modifications to tooth number, size, shape and position. For example, bats with short snouts lack certain teeth, presumably due to a lack of space. Species with longer jaws have room for more teeth -- and, like humans, their total tooth complement is closer to what the ancestor of placental mammals had.

According to the research team behind this study, comparing noctilionoid species can reveal a lot about how mammalian faces evolved and developed, particularly jaws and teeth. And as a bonus, they can also answer some outstanding questions about how our own pearly whites form and grow.

"Bats have all four types of teeth -- incisors, canines, premolars and molars -- just like we do," said co-author Sharlene Santana, a University of Washington professor of biology and curator of mammals at the Burke Museum of Natural History & Culture. "And noctilionoid bats evolved a huge diversity of diets in as little as 25 million years, which is a very short amount of time for these adaptations to occur."

"There are noctilionoid species that have short faces like bulldogs with powerful jaws that can bite the tough exterior of the fruits that they eat. Other species have long snouts to help them drink nectar from flowers. How did this diversity evolve so quickly? What had to change in their jaws and teeth to make this possible?" said lead author Alexa Sadier, an incoming faculty member at the Institute of Evolutionary Science of Montpellier in France, who began this project as a postdoctoral researcher at the University California, Los Angeles.

Scientists don't know what triggered this frenzy of dietary adaptation in noctilionoid bats. But today different noctilionoid species feast on insects, fruit, nectar, fish and even blood -- since this group also includes the infamous vampire bats.

The team used CT scans and other methods to analyze the shapes and sizes of jaws, premolars and molars in more than 100 noctilionoid species. The bats included both museum specimens and a limited number of wild bats captured for study purposes. The researchers compared the relative sizes of teeth and other cranial features among species with different types of diets, and used mathematical modeling to determine how those differences are generated during development.

The team found that, in noctilionoid bats, certain "developmental rules" caused them to generate the right assortment of teeth to fit in their diet-formed grins. For example, bats with long jaws -- like nectar-feeders -- or intermediate jaws, like many insect-eaters, tended to have the usual complement of three premolars and three molars on each side of the jaw. But bats with short jaws, including most fruit-eating bats, tended to ditch the middle premolar or the back molar, if not both.

"When you have more space, you can have more teeth," said Sadier. "But for bats with a shorter space, even though they have a more powerful bite, you simply run out of room for all these teeth."

Having a shorter jaw may also explain why many short-faced bats also tended to have wider front molars.

"The first teeth to appear tend to grow bigger since there is not enough space for the next ones to emerge," said Sadier.

"This project is giving us the opportunity to actually test some of the assumptions that have been made about how tooth growth, shape and size are regulated in mammals," said Santana. "We know surprisingly little about how these very important structures develop!"

Many studies about mammalian tooth development were done in mice, which have only molars and heavily modified incisors. Scientists are not entirely sure if the genes and developmental patterns that control tooth development in mice also operate in mammals with more "ancestral" sets of chompers -- like bats and humans.

Sadier, Santana and their colleagues believe their project, which is ongoing, can start to answer these questions in bats -- along with many other outstanding questions about how evolution shapes mammalian features. They're expanding this study to include noctilionoid incisors and canines, and hope to uncover more of the genetic and developmental mechanisms that control tooth development in this diverse group of bats.

"We see such strong selective pressures in these bats: Shapes have to closely match their function," said Santana. "I think there are many more evolutionary secrets hidden in these species."

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Fiber from crustaceans, insects, mushrooms promotes digestion

Who can forget the stomach-churning moments when "Survivor" contestants forced down crunchy insects, among other unappetizing edibles, for a chance to win $1 million? In daring culinary challenges, the TV show's contestants exhibited gastronomic bravery as viewers watched in discomfort.

Digesting a crunchy critter starts with the audible grinding of its rigid protective covering -- the exoskeleton. Unpalatable as it may sound, the hard cover might be good for the metabolism, according to a new study, in mice, from Washington University School of Medicine in St. Louis.

The researchers, led by Steven Van Dyken, PhD, an assistant professor of pathology & immunology, found in mice that digesting chitin, an abundant dietary fiber in insect exoskeletons and also mushrooms and crustacean shells, engages the immune system. An active immune response was linked to less weight gain, reduced body fat and a resistance to obesity.

"Obesity is an epidemic," Van Dyken said. "What we put into our bodies has a profound effect on our physiology and on how we metabolize food. We're investigating ways to counteract obesity based on what we learn about how the immune system is engaged by diet."

The study is published Sept. 7 in Science.

The immune system is well known for safeguarding the body against various threats, including bacteria, viruses, allergens and even cancer. The researchers found that a particular arm of the immune system also is involved in chitin digestion. Stomach distention after chitin ingestion activates an innate immune response that triggers stomach cells to ramp up production of enzymes, known as chitinases, that break down chitin. Of note, chitin is insoluble -- incapable of being dissolved in liquid -- and thus requires enzymes and harsh acidic conditions to digest.

Do-Hyun Kim, PhD, a postdoctoral research associate and first author on the study, performed the experiments in germ-free mice lacking intestinal bacteria. His results show that chitin activates immune responses in the absence of bacteria.

"We think chitin digestion mainly relies on the host's own chitinases," Van Dyken said. "The stomach cells change their enzymatic output through a process we refer to as adaptation. But it is surprising that this process is happening without microbial input, because bacteria in the gastrointestinal tract are also sources of chitinases that degrade chitin." Van Dyken noted that in mice with intestinal bacteria, dietary chitin altered the bacterial composition in the lower gastrointestinal tract, suggesting that gut bacteria also adapt to chitin-containing food after it leaves the stomach.

The research team found that the greatest impact on obesity in mice occurred when chitin activated the immune system but was not digested. Mice fed a high-fat diet also were given chitin. Some mice lacked the ability to produce chitinases to break down chitin. The mice that ate chitin but couldn't break it down gained the least amount of weight, had the lowest body fat measurements and resisted obesity, compared with mice that didn't eat chitin and with those that did but could break it down.

If the mice could break down chitin, they still benefited metabolically, but they adapted by overproducing chitinases to extract nutrients from chitin.

Van Dyken and his team next plan to follow up on their findings in people, with a goal of determining whether chitin could be added to human diets to help control obesity.

Read more at Science Daily

Most species are rare, but not very rare

More than 100 years of observations in nature have revealed a universal pattern of species abundances: Most species are rare but not very rare, and only a few species are very common. These so-called global species abundance distributions have become fully unveiled for some well-monitored species groups, such as birds. For other species groups, such as insects, however, the veil remains partially unlifted. These are the findings of an international team of researchers led by the German Centre for Integrative Biodiversity Research (iDiv), the Martin Luther University Halle-Wittenberg (MLU) and the University of Florida (UF), published in the journal Nature Ecology and Evolution. The study demonstrates how important biodiversity monitoring is for detecting species abundances on planet Earth and for understanding how they change.

"Who can explain why one species ranges widely and is very numerous, and why another allied species has a narrow range and is rare?" This question was asked by Charles Darwin in his ground-breaking book "The Origin of Species," published over 150 years ago. A related challenge has been to understand how many species are common (numerous) and how many are rare, the so-called global species abundance distribution (gSAD).

Two main gSAD models have been proposed in the last century: R. A. Fisher, a statistician and biologist, proposed that most species are very rare and that the number of species declines for more common species (so-called log-series model). On the other hand, F. W. Preston, an engineer and ecologist, argued that only few species are actually very rare and that most species have some intermediate level of commonness (so-called log-normal model). However, until now and despite decades of research, scientists did not know which model describes the planet's true gSAD.

Solving this problem calls for vast amounts of data. The study authors used data from the Global Biodiversity Information Facility (GBIF) and downloaded data representing over 1 billion species observations in nature from 1900 to 2019.

"The GBIF database is an amazing resource for all sorts of biodiversity related research, particularly because it brings together both data collected from professional and citizen scientists all over the world," says first author Dr Corey Callaghan. He began the study while working at iDiv and MLU and is now working at the UF.

Callaghan and his fellow researchers divided the downloaded data into 39 species groups, for instance, birds, insects, or mammals. For each, they compiled the respective global species abundance distribution (gSAD).

The researchers detected a potentially universal pattern, which emerges once the species abundance distribution is fully unveiled: Most species are rare but not very rare, and only a few species are very common, as predicted in the log-normal model. However, the researchers also found that the veil has been fully lifted only for a few species groups like cycads and birds. For all other species groups, the data are yet insufficient.

"If you don't have enough data, it looks as though most species are very rare," says senior author Prof Henrique Pereira, research group head at iDiv and the MLU. "But by adding more and more observations, the picture changes. You start seeing that there are, in fact, more rare species than very rare species. You can see this shift for cycads and birds when comparing the species observations from back in 1900, when less data was available, with the more comprehensive species observations we have today. It is fascinating: we can clearly see the phenomenon of unveiling the full species abundance distribution, as predicted by Preston several decades ago, but only now demonstrated at the scale of the entire planet."

"Even though we have been recording observations for decades, we have only lifted the veil for a few species groups," says Callaghan. "We still have a long way to go. But GBIF and the sharing of data really represents the future of biodiversity research and monitoring, to me."

The new study's findings enable scientists to assess how far the gSADs have been unveiled for different species groups. This allows for answering another long-standing research question: How many species are out there? This study finds that while for some groups like birds, nearly all species have been identified, this is not the case for other taxa such as insects and cephalopods.

Read more at Science Daily

Three-eyed distant relative of insects and crustaceans reveals amazing detail of early animal evolution

A team from the University of Leicester, Yunnan Key Laboratory for Palaeobiology and the Institute of Palaeontology at Yunnan University, Chengjiang Fossil Museum, and the Natural History Museum in London, have redescribed a unique fossil animal from rocks nearly 520 million years old that fills in a gap in our understanding of the evolution of animals known as arthropods.

The animal, which has the scientific name Kylinxia, was imaged using a CT scanner which revealed its soft anatomy buried in the rock. The size of a large shrimp, its surprising features include three eyes on the head and a pair of fearsome limbs presumably used to catch prey.

The study is published this week in the high impact journal Current Biology.

Fossils of many kinds of marine animals first appear in rocks from about half a billion years ago and signal a time when complex ecosystems were developing in the world's oceans. One of the key localities for such fossils is the area around the town of Chengjiang in southern China, where the fossils in this study were collected by the Chinese team. The fossils were recovered from the Cambrian Chengjiang biota of China's Yunnan Province, from which over 250 species of exceptionally preserved fossil organisms have been described.

The new find is important for deciphering the history of arthropods. These are animals whose bodies are divided into segments, most of which bear a paired of jointed limbs, like crabs, lobsters, insects, and spiders.

Although there are plenty of arthropods in the fossil record -- most famously the trilobites -- the vast majority only preserve their hard skeletons. Because the new Chinese material is preserved nearly complete, the team were able to image the head of Kylinxia, identifying six segments: the front one bearing eyes, the second with a pair of large grasping limbs, and the other four each bearing a pair of jointed limbs.

Lead author of the study Robert O'Flynn, a PhD student at the University of Leicester School of Geography, Geology and the Environment, said: "The preservation of the fossil animal is amazing. After CT-scanning we can digitally turn it around and literally stare into the face of something that was alive over 500 million years ago. As we spun the animal around, we could see that its head possesses six segments, just as in many living arthropods."

Professor Mark Williams, Robert's primary supervisor at the University of Leicester, said: "Kylinxia, and the Chengjiang biota whence it came, are instrumental to building our understanding of early euarthropod evolution. I like to think that similar discoveries will continue to be made by Robert."

Professor Yu Liu from the Yunnan Key Laboratory for Palaeobiology said: "Robert and I were examining the micro-CT data as part of his doctoral thesis in the hope of refining and correcting previous interpretation of head structures in this genus, Kylinxia. Amazingly, we found that its head is composed of six segments, as in, e.g., insects."

Dr Greg Edgecombe from the Natural History Museum added: "Most of our theories on how the head of arthropods evolved were based on these early-branching species having fewer segments than living species. Discovering two previously undetected pairs of legs in Kylinxia suggests that living arthropods inherited a six-segmented head from an ancestor at least 518 million years ago."

Read more at Science Daily

Weather anomalies are keeping insects active longer

As Earth's climate continues to warm due to the emission of greenhouse gasses, extreme and anomalous weather events are becoming more common. But predicting and analyzing the effects of what is, by definition, an anomaly can be tricky.

Scientists say museum specimens can help. In the first study of its kind, researchers at the University of Florida used natural history specimens to show that unseasonably warm and cold days can prolong the active period of moths and butterflies by nearly a month.

"The results are not at all what we expected," said lead author Robert Guralnick, curator of biodiversity informatics at the Florida Museum of Natural History.

Most studies view climate change and its consequences through a periscope of average temperature increases. As temperature goes up over time, the plants and animals in a particular region become active earlier in the spring, delay dormancy until later in the fall and slowly shift their ranges to align with the climate in which they're best suited to survive.

Erratic weather adds a layer of complexity to these patterns, with unknown consequences that erect an opaque screen ahead of scientists attempting to predict the future of global ecosystems.

"There had been hints in the scientific literature that weather anomalies can have cumulative effects on ecosystems, but there wasn't anything that directly addressed this question at a broad scale," Guralnick said.

This omission, he explained, was due primarily to a lack of sufficient data. While climate data has been reliably collected in many areas of the world for more than a century, records documenting the location and activity of organisms are harder to come by.

Natural history museums have been increasingly regarded as a potential solution. The oldest museums have accumulated specimens for hundreds of years, and recent efforts to digitize collections have made their contents widely available. But digital museum records come with their own unique pitfalls and drawbacks.

In 2022, study co-author Michael Belitz constructed a dataset of moths and butterflies from museum collections to chart a course for other researchers hoping to use similar data. The result was a comprehensive instruction manual for how to gather, organize and analyze information from natural history specimens.

With this robust resource at their disposal, Belitz and his colleagues wanted to see if they could detect a signal from aberrant weather patterns. Restricting their analyses to the eastern United States, the authors used records for 139 moth and butterfly species collected from the 1940s through the 2010s.

Their results were unequivocal: Unusually warm and cold weather has significantly altered insect activity to a greater extent than the average increase in global temperature for the last several decades.

The location and timing of extreme weather events influenced how insects responded. In higher latitudes, warm days in winter meant moths and butterflies became active earlier in the spring. Unusually cold days kept insects at all latitudes active longer, and the combination of exceptionally high and low temperatures had the strongest effect.

"If you have a succession of abnormally cold and warm days, it limits the ability of insects to function at peak performance," Guralnick said. "If cold doesn't kill you, it slows you down, and it might force insects into a torpor. Insects can recover from the cold snaps pretty quickly and go on to have longer lifespans as a direct result of sudden temperature declines."

Insects being active for longer periods of time might initially seem like a good thing. But rather than a counterweight to the negative repercussions of climate change, co-author Lindsay Campbell -- who studies mosquitos -- points out that longer or altered insect lifespans may also mean more opportunities for pathogen transmission.

"There's a correlation between El Niño and rift valley fever outbreaks in East Africa, and there are anecdotal observations that show unusually warm or hot and dry springs, followed by a heavy precipitation event, are also linked with increased outbreaks," said Campbell, an assistant professor at the University of Florida.

Long-term ecosystem stability is also entirely dependent on the synchronized activity of its constituent parts, and plants may not respond to extreme weather in the same way as insects. If moths and butterflies take flight too early, they risk encountering plants that haven't yet produced leaves or flowers, expending their energy in a vain search for food.

And with a constantly shifting baseline for what constitutes 'extreme,' it's unclear if insects will be able to keep pace with the changes.

Read more at Science Daily

The evolution of honey bee brains

Researchers have proposed a new model for the evolution of higher brain functions and behaviors in the Hymenoptera order of insects. The team compared the Kenyon cells, a type of neuronal cell, in the mushroom bodies (a part of the insect brain involved in learning, memory and sensory integration) of "primitive" sawflies and sophisticated honey bees. They found that three diverse, specialized Kenyon cell subtypes in honey bee brains appear to have evolved from a single, multifunctional Kenyon cell-subtype ancestor. In the future, this research could help us better understand the evolution of some of our own higher brain functions and behaviors.

Are you "busy as a bee," a "social butterfly" or a "fly on the wall"? There are many ways we compare our behavior to that of insects, and as it turns out there may be more to it than just fun idioms. Studying insects could help us understand not only how their behavior has evolved, but also the behavior of highly evolved animals, including ourselves. Mammalian brains are big and complex, so it is difficult to identify which behaviors and neural and genetic changes have co-developed over time. By comparison, insect brains are much smaller and simpler, making them useful models for study.

"In 2017, we reported that the complexity of Kenyon cell (KC) subtypes in mushroom bodies in insect brains increases with the behavioral diversification in Hymenoptera (a large and varied order of insects)" explained Professor Takeo Kubo from the Graduate School of Science at the University of Tokyo and co-author of the current study. "In other words, the more KC subtypes an insect has, the more complex its brain and the behaviors it may exhibit. But we didn't know how these different subtypes evolved. That was the stimulus for this new study."

The team from the University of Tokyo and Japan's National Agriculture and Food Research Organization (NARO) chose two Hymenoptera species as representatives for different behaviors: the solitary turnip sawfly (which has a single KC subtype) and the sophisticated, social honey bee (which has three KC subtypes). As the sawfly has a more "primitive" brain, it is thought to contain some ancestral properties of the honey bee brain. To uncover the potential evolutionary pathways between them, the researchers used transcriptome analysis to identify the gene expression profiles (the genetic activity) of the various KC subtypes and speculate their functions.

"I was surprised that each of the three KC subtypes in the honey bee showed comparable similarity to the single KC type in the sawfly," said Assistant Professor Hiroki Kohno, co-author from the Graduate School of Science. "Based on our initial comparative analysis of several genes, we had previously supposed that additional KC subtypes had been added one by one. However, they appear to have been separated from a multifunctional ancestral type, through functional segregation and specialization." As the number of KC subtypes increased, each subtype almost equally inherited some distinct properties from an ancestral KC. These then modified in different ways, resulting in their varied present-day functions.

The researchers wanted a specific behavioral example of how ancestral KC functions are present in both the sawfly and the honey bee. So, they trained sawflies to engage in a common honey bee behavior test, where they learn to associate an odor stimulus with a reward. Although challenging at first, the team was eventually able to engage the sawflies in the memory task. The researchers then manipulated a gene called CaMKII in sawfly larvae, which in honey bees is associated with forming long-term memory, a KC function. When the larvae became adults, their long-term memory was impaired, indicating that the gene plays a similar role in both sawflies and honey bees. Although CaMKII was expressed (i.e., was active) across the entire single KC subtype in sawflies, in honey bees, it was preferentially expressed in only one KC subtype. This suggests that the role of CaMKII in long-term memory was passed down to the specific KC subtype in the honey bee.

Despite differences in the size and complexity of insect and mammalian brains, there are commonalities in terms of function and the basic architecture of the nervous system. That is why the model proposed in this study for the evolution and diversification of KC subtypes may help towards better understanding the evolution of our own behavior. Next, the team is interested in studying KC types acquired in parallel with social behaviors, such as the honey bee's "waggle dance."

Read more at Science Daily

Scientists complete first map of an insect brain

Researchers have completed the most advanced brain map to date, that of an insect, a landmark achievement in neuroscience that brings scientists closer to true understanding of the mechanism of thought.

The international team led by Johns Hopkins University and the University of Cambridge produced a breathtakingly detailed diagram tracing every neural connection in the brain of a larval fruit fly, an archetypal scientific model with brains comparable to humans.

The work, likely to underpin future brain research and to inspire new machine learning architectures, appears today in the journal Science.

"If we want to understand who we are and how we think, part of that is understanding the mechanism of thought," said senior author Joshua T. Vogelstein, a Johns Hopkins biomedical engineer who specializes in data-driven projects including connectomics, the study of nervous system connections. "And the key to that is knowing how neurons connect with each other."

The first attempt at mapping a brain -- a 14-year study of the roundworm begun in the 1970s, resulted in a partial map and a Nobel Prize. Since then, partial connectomes have been mapped in many systems, including flies, mice, and even humans, but these reconstructions typically only represent only a tiny fraction of the total brain. Comprehensive connectomes have only been generated for several small species with a few hundred to a few thousand neurons in their bodies-a roundworm, a larval sea squirt, and a larval marine annelid worm.

This team's connectome of a baby fruit fly, Drosophila melanogaster larva, is the most complete as well as the most expansive map of an entire insect brain ever completed. It includes 3,016 neurons and every connection between them: 548,000.

"It's been 50 years and this is the first brain connectome. It's a flag in the sand that we can do this," Vogelstein said. "Everything has been working up to this."

Mapping whole brains is difficult and extremely time-consuming, even with the best modern technology. Getting a complete cellular-level picture of a brain requires slicing the brain into hundreds or thousands of individual tissue samples, all of which have to be imaged with electron microscopes before the painstaking process of reconstructing all those pieces, neuron by neuron, into a full, accurate portrait of a brain. It took more than a decade to do that with the baby fruit fly. The brain of a mouse is estimated to be a million times larger than that of a baby fruit fly, meaning the chance of mapping anything close to a human brain isn't likely in the near future, maybe not even in our lifetimes.

The team purposely chose the fruit fly larva because, for an insect, the species shares much of its fundamental biology with humans, including a comparable genetic foundation. It also has rich learning and decision-making behaviors, making it a useful model organism in neuroscience. And for practical purposes, its relatively compact brain can be imaged and its circuits reconstructed within a reasonable time frame.

Even so, the work took the University of Cambridge and Johns Hopkins 12 years. The imaging alone took about a day per neuron.

Cambridge researchers created the high-resolution images of the brain and manually studied them to find individual neurons, rigorously tracing each one and linking their synaptic connections.

Cambridge handed off the data to Johns Hopkins, where the team spent more than three years using original code they created to analyze the brain's connectivity. The Johns Hopkins team developed techniques to find groups of neurons based on shared connectivity patterns, and then analyzed how information could propagate through the brain.

In the end, the full team charted every neuron and every connection, and categorized each neuron by the role it plays in the brain. They found that the brain's busiest circuits were those that led to and away from neurons of the learning center.

The methods Johns Hopkins developed are applicable to any brain connection project, and their code is available to whoever attempts to map an even larger animal brain, Vogelstein said, adding that despite the challenges, scientists are expected to take on the mouse, possibly within the next decade. Other teams are already working on a map of the adult fruit fly brain. Co-first author Benjamin Pedigo, a Johns Hopkins doctoral candidate in Biomedical Engineering, expects the team's code could help reveal important comparisons between connections in the adult and larval brain. As connectomes are generated for more larva and from other related species, Pedigo expects their analysis techniques could lead to better understanding of variations in brain wiring.

The fruit fly larva work showed circuit features that were strikingly reminiscent of prominent and powerful machine learning architectures. The team expects continued study will reveal even more computational principles and potentially inspire new artificial intelligence systems.

"What we learned about code for fruit flies will have implications for the code for humans," Vogelstein said. "That's what we want to understand -- how to write a program that leads to a human brain network."

Read more at Science Daily

Mulching time of forest meadows influences insect diversity

Mulching is a possible management method for forest meadows and is important to their upkeep. During the process, the meadow is cut and the cuttings are shredded and left on the meadow. Despite its significance, the effects of this method on insects living in this habitat has rarely been studied up to now. Dr. Maria M. Georgi of the team working with the head of the University of Freiburg's Chair of Nature Conservation and Landscape Ecology -- Prof. Dr. Alexandra-Maria Klein, and her colleagues studied this in-depth. The result: Nearly all the mulching times examined had a negative impact on insect larvae and flower-visiting insects which are found on forest meadows. Georgi says, "Management is important for the maintenance of forest meadows. That is why we're proposing alternative types of mulching be applied in future to improve conservation of the insects living there if no opportunity to apply another method, such as cut, is available."

Meadows are important to the forest; mulching is important to the meadows

Forest meadows are often managed to attract game animals. This reduces their browsing of young plants -- so the grazing of leaves and twigs -- in the surrounding woods. Management is required to retain forest meadows. Otherwise, the forest would spread increasingly and the meadow would disappear. Compared to other methods, mulching is more effective in terms of cost and labor intensity. During the processes the meadow is mowed and the cuttings are shredded and left on the meadow. Although the impact of cut on plant and insect diversity has been intensively investigated, the opposite had been the case for mulching up to now.

Examining of four mulching times

The study was carried out at 24 locations in the northern Black Forest. The focus was on insect larvae and insect flower-visitors. The researchers examined how different mulching times affected these insects. Six locations were designated for a control group. They were not mulched. These were compared with six meadows that were mulched either in June or September, as well as six additional meadows that were mulched both in June and September. In terms of insect larvae, sawflies (Symphyta) accounted for 45 percent of the population studied, with butterflies (Lepidoptera) making up 44 percent. Hover files (Syrphidae) dominated the flower-visiting insects. They made up a share of 80 percent.

September mulching protects flower-visiting insects

For the insect larvae, all three mulching times studied had a negative impact on numbers compared to the control group. The findings were similar for the flower-visiting insects. Here, mulching in June, as well as mulching in June and September, had a negative impact on the number of insects counted. Yet September mulching had no impact in the case of flower-visitors. Georgi concludes, "On the basis of our results, we can recommend mulching in September in order to protect flower-visitors."

Read more at Science Daily

Honey bee life spans are 50% shorter today than they were 50 years ago

A new study by University of Maryland entomologists shows that the lifespan for individual honey bees kept in a controlled, laboratory environment is 50% shorter than it was in the 1970s. When scientists modeled the effect of today's shorter lifespans, the results corresponded with the increased colony loss and reduced honey production trends seen by U.S. beekeepers in recent decades.

Colony turnover is an accepted factor in the beekeeping business, as bee colonies naturally age and die off. But over the past decade, U.S. beekeepers have reported high loss rates, which has meant having to replace more colonies to keep operations viable. In an effort to understand why, researchers have focused on environmental stressors, diseases, parasites, pesticide exposure and nutrition.

This is the first study to show an overall decline in honey bee lifespan potentially independent of environmental stressors, hinting that genetics may be influencing the broader trends seen in the beekeeping industry. The study was published November 14, 2022, in the journal Scientific Reports.

"We're isolating bees from the colony life just before they emerge as adults, so whatever is reducing their lifespan is happening before that point," said Anthony Nearman, a Ph.D. student in the Department of Entomology and lead author of the study. "This introduces the idea of a genetic component. If this hypothesis is right, it also points to a possible solution. If we can isolate some genetic factors, then maybe we can breed for longer-lived honey bees."

Nearman first noticed the decline in lifespan while conducting a study with entomology associate professor Dennis van Engelsdorp on standardized protocols for rearing adult bees in the laboratory. Replicating earlier studies, the researchers collected bee pupae from honey bee hives when the pupae were within 24 hours of emerging from the wax cells they are reared in. The collected bees finished growing in an incubator and were then kept as adults in special cages.

Nearman was evaluating the effect of supplementing the caged bees' sugar water diet with plain water to better mimic natural conditions when he noticed that, regardless of diet, the median lifespan of his caged bees was half that of caged bees in similar experiments in the 1970s. (17.7 days today versus 34.3 days in the 1970s.) This prompted a deeper review of published laboratory studies over the past 50 years.

"When I plotted the lifespans over time, I realized, wow, there's actually this huge time effect going on," Nearman said. "Standardized protocols for rearing honey bees in the lab weren't really formalized until the 2000s, so you would think that lifespans would be longer or unchanged, because we're getting better at this, right? Instead, we saw a doubling of mortality rate."

Although a laboratory environment is very different from a colony, historical records of lab-kept bees suggest a similar lifespan to colony bees, and scientists generally assume that isolated factors that reduce lifespan in one environment will also reduce it in another. Previous studies had also shown that in the real world, shorter honey bee lifespans corresponded to less foraging time and lower honey production. This is the first study to connect those factors to colony turnover rates.

When the team modeled the effect of a 50% reduction in lifespan on a beekeeping operation, where lost colonies are replaced annually, the resulting loss rates were around 33%. This is very similar to the average overwinter and annual loss rates of 30% and 40% reported by beekeepers over the past 14 years.

Nearman and vanEngelsdorp noted that their lab-kept bees could be experiencing some sort of low-level viral contamination or pesticide exposure during their larval stage, when they're brooding in the hive and worker bees are feeding them. But the bees have not shown overt symptoms of those exposures and a genetic component to longevity has been shown in other insects such as fruit flies.

Read more at Science Daily

Entomologists issue warning about effects of climate change on insects

In a new scientific review, a team of 70 scientists from 19 countries warned that if no steps are taken to shield insects from the consequences of climate change, it will "drastically reduce our ability to build a sustainable future based on healthy, functional ecosystems."

Citing research from around the world, the team painted a bleak picture of the short- and long-term effects of climate change on insects, many of which have been in a state of decline for decades. Global warming and extreme weather events are already threatening some insects with extinction -- and it will only get worse if current trends continue, scientists say. Some insects will be forced to move to cooler climes to survive, while others will face impacts to their fertility, life cycle and interactions with other species.

Such drastic disruptions to ecosystems could ultimately come back to bite people, explained Anahí Espíndola, an assistant professor of entomology at the University of Maryland and one of the paper's co-authors.

"We need to realize, as humans, that we are one species out of millions of species, and there's no reason for us to assume that we're never going to go extinct," Espíndola said. "These changes to insects can affect our species in pretty drastic ways."

Insects play a central role in ecosystems by recycling nutrients and nourishing other organisms further up the food chain, including humans. In addition, much of the world's food supply depends on pollinators like bees and butterflies, and healthy ecosystems help keep the number of pests and disease-carrying insects in check.

These are just a few of the ecosystem services that could be compromised by climate change, the team of scientists cautioned. Unlike mammals, many insects are ectotherms, which means they are unable to regulate their own body temperature. Because they are so dependent on external conditions, they may respond to climate change more acutely than other animals.

One way that insects cope with climate change is by shifting their range, or permanently relocating to places with lower temperatures. According to one study cited by Espíndola and other scientists, the ranges of nearly half of all insect species will diminish by 50% or more if the planet heats up 3.2°C. If warming is limited to 1.5°C -- the goal of the global Paris Agreement on climate change -- the ranges of 6% of insects will be affected.

Espíndola, who studies the ways in which species respond to environmental changes over time, contributed to the sections of the paper that address range shifts. She explained that drastic changes to a species' range can jeopardize their genetic diversity, potentially hampering their ability to adapt and survive.

On the other hand, climate change may make some insects more pervasive -- to the detriment of human health and agriculture. Global warming is expected to expand the geographical range of some disease vectors (such as mosquitoes) and crop-eating pests.

"Many pests are actually pretty generalist, so that means they are able to feed on many different types of plants," Espíndola said. "And those are the insects that -- based on the data -- seem to be the least negatively affected by climate change."

The team noted that the effects of climate change are often compounded by other human-caused impacts, such as habitat loss, pollution and the introduction of invasive species. Combined, these stressors make it more difficult for insects to adapt to changes in their environment.

Though these effects are already being felt by insects, it is not too late to take action. The paper outlined steps that policymakers and the public can take to protect insects and their habitats. Scientists recommended "transformative action" in six areas: phasing out fossil fuels, curbing air pollutants, restoring and permanently protecting ecosystems, promoting mostly plant-based diets, moving towards a circular economy and stabilizing the global human population.

The paper's lead author, Jeffrey Harvey of the Netherlands Institute of Ecology (NIOO-KNAW) and Vrije Universiteit Amsterdam, said in a statement that urgent action is needed to protect insects and the ecosystems they support.

"Insects are tough little critters, and we should be relieved that there is still room to correct our mistakes," Harvey said. "We really need to enact policies to stabilize the global climate. In the meantime, at both government and individual levels, we can all pitch in and make urban and rural landscapes more insect-friendly."

The paper suggested ways that individuals can help, including managing public, private or urban gardens and other green spaces in a more ecologically-friendly way -- for instance, incorporating native plants into the mix and avoiding pesticides and significant changes in land usage when possible.

Read more at Science Daily

Mathematicians explain how some fireflies flash in sync

Stake out in Pennsylvania's Cook State Forest at the right time of year and you can see one of nature's great light shows: swarms of fireflies that synchronize their flashes like strings of Christmas lights in the dark.

A new study by Pitt mathematicians shows that math borrowed from neuroscience can describe how swarms of these unique insects coordinate their light show, capturing key details about how they behave in the wild.

"This firefly has a quick sequence of flashes, and then a big pause before the next burst," said Jonathan Rubin, professor and chair of the Department of Mathematics in the Kenneth P. Dietrich School of Arts and Sciences. "We knew a good framework for modeling this that could capture a lot of the features, and we were curious how far we could push it."

Male fireflies produce a glow from their abdomens to call out to potential mates, sending out blinking patterns in the dark to woo females of their own species. Synchronous fireflies of the species Photinus carolinus take it a step further, coordinating their blinking throughout entire swarms. It's a rare trait -- there are only a handful of such species in North America -- and the striking lights they produce draw crowds to locations where the insects are known to gather.

They've also attracted the interest of mathematicians seeking to understand how they synchronize their blinks. It's just one example of how synchronization can evolve from randomness, a process that has intrigued mathematicians for centuries. One famous example from the 1600s showed that pendulum clocks hung next to one another synchronize through vibrations that travel through the wall, and the same branch of math can be used to describe everything from the action of intestines to audience members clapping.

"Synchrony is important for a lot of things, good and bad," said co-author Bard Ermentrout, distinguished professor of mathematics in the Dietrich School. "Physicists, mathematicians, we're all interested in synchronization."

To crack the fireflies' light show, the Pitt team used a more complex model called an "elliptic burster" that's used to describe the behavior of brain cells. The duo, along with then-undergrad Madeline McCrea (A&S '22) published details of their model Oct. 26 in the Journal of the Royal Society Interface.

The first step was to simulate the blinks of a single firefly, then expand to a pair to see how they matched their flashing rates to one another. Next, the team moved to a bigger swarm of simulated insects to see how number, distance and flying speed affect the resulting blinks.

Varying the distances each firefly could "see" each other and respond to one another changed the insects' light show, they found: By tweaking the parameters, they could produce patterns of blinks that looked like either ripples or spirals.

The results line up with several recently published observations about real-life synchronous fireflies -- for instance, that individual fireflies are inconsistent while groups flash more regularly, and that when new fireflies join the swarm, they're already perfectly in time.

"It captured a lot of the finer details that they saw in the biology, which was cool," said Ermentrout. "We didn't expect that."

The math also makes some predictions that could inform firefly research -- for instance, light pollution and the time of day both may alter the patterns produced by fireflies by changing how well they can see one another's blinks.

McCrea worked on the research as an undergraduate supported by the department's Painter Fellowship, which gave her funding to work on the project through the summer. "She was awesome working on this project, and really persistent," said Rubin.

The team is the first to use this particular brain-cell framework to model fireflies, which several different research teams are trying to understand using different types of math. "It's more of a wild west research topic," said Ermentrout. "It's early days, and who knows where things are going to go from here?"

Ermentrout and Rubin also hopeful that the math will capture the imagination of those inspired by the glow of fireflies. In the midst of this project, Rubin himself decided to head up to Cook State Forest to see if he could spot his research subjects firsthand.

Read more at Science Daily

We need to stop thinking of insects as 'creepy crawlies' and recognize their keystone role in ecosystems

We need to stop thinking of insects as creepy crawlies and focus on the huge benefits they bring to people and the natural environment, scientists say.

The widespread and deeply ingrained cultural perception of insects as creepy crawlies is a key factor holding back the public's appreciation of the role they play within ecosystems. This perception is in part reflected in government biodiversity policy inaction across the globe, they argue.

This point is among a range of actions highlighted as part of a new paper published in Ecology and Evolution produced by an international team of entomologists which outlines a 'battle plan' including steps needed to prevent further insect losses across the globe.

Led by Dr Philip Donkersley of Lancaster University and co-authored by scientists from the University of Hong Kong, the Czech Academy of Sciences and Harper Adams University, the paper is a call to action targeted at other entomologists to step up advocacy for insects.

Despite 30 years of intergovernmental reports highlighting biodiversity targets, global insect abundance, biomass and diversity continues to decline. The paper considers the lack of progress in protecting insects and why meaningful change has not happened.

"Biodiversity, including insect, declines are often unintended consequences of human activities with human wellbeing nearly always trumping nature conservation, and this is likely to continue until we reach a point where we see flat-lining ecosystems are detrimental to our own species," said Dr Donkersley. "Intergovernmental action has been slow to respond, kicking in only when change becomes impossible to ignore. If we are to see political attitudes and actions change then first societies' perception of insects needs to be addressed."

The paper highlights the range of benefits that insects bring, including some that are lesser known. These benefits include fundamental roles within ecosystems through interactions with plants including as pollinators, as a food for other animals, and as a food source for people in many parts of the world. Other benefits the authors highlight include insects' contributions to wellbeing, culture and innovation, such as the benefits people derive from seeing butterflies in parks and gardens, their inclusion in poetry and literature, and their inspiration for a range of technologies, cosmetics and pharmaceuticals.

The researchers have outlined strategic priorities in their action plan to help support the conservation of insects. These include:
 

• to proactively and publicly address government inaction
• highlighting the technological developments we owe to the insects, and that there is a lot still to be discovered
• aligning with bird, plant and mammal conservation groups to show species interdependencies and knock-on benefits insect conservation has for other animals
• Engage public and school students with the wonders of the insect world to counter perceptions of insects as threatening 'creepy crawlies'

"The benefits we gain from the insect world are broad, yet aversion of phobias of invertebrates are common and stand firmly in the path of their conservation," said Dr Donkersley. "We need to move beyond this mindset and appreciate the huge role they play in ecosystems, foodchains, mental health, and even technological innovation.

"This perception change is a crucial step, alongside other measures we outline in this paper. Immediate and substantial actions are needed to protect insect species in order to maintain global ecosystem stability."

Read more at Science Daily

Unprecedented levels of insects damaging plants

Insects today are causing unprecedented levels of damage to plants, even as insect numbers decline, according to new research led by University of Wyoming scientists.

The first-of-its-kind study compares insect herbivore damage of modern-era plants with that of fossilized leaves from as far back as the Late Cretaceous period, nearly 67 million years ago. The findings appear in the  journal Proceedings of the National Academy of Sciences.

"Our work bridges the gap between those who use fossils to study plant-insect interactions over deep time and those who study such interactions in a modern context with fresh leaf material," says the lead researcher, UW Ph.D. graduate Lauren Azevedo-Schmidt, now a postdoctoral research associate at the University of Maine. "The difference in insect damage between the modern era and the fossilized record is striking."

Azevedo-Schmidt conducted the research along with UW Department of Botany and Department of Geology and Geophysics Professor Ellen Currano, and Assistant Professor Emily Meineke of the University of California-Davis.

The study examined fossilized leaves with insect feeding damage from the Late Cretaceous through the Pleistocene era, a little over 2 million years ago, and compared them with leaves collected by Azevedo-Schmidt from three modern forests. The detailed research looked at different types of damage caused by insects, finding marked increases in all recent damage compared to the fossil record.

"Our results demonstrate that plants in the modern era are experiencing unprecedented levels of insect damage, despite widespread insect declines," wrote the scientists, who suggest that the disparity can be explained by human activity.

More research is necessary to determine the precise causes of increased insect damage to plants, but the scientists say a warming climate, urbanization and introduction of invasive species likely have had a major impact.

"We hypothesize that humans have influenced (insect) damage frequencies and diversities within modern forests, with the most human impact occurring after the Industrial Revolution," the researchers wrote. "Consistent with this hypothesis, herbarium specimens from the early 2000s were 23 percent more likely to have insect damage than specimens collected in the early 1900s, a pattern that has been linked to climate warming."

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How tardigrades bear dehydration

Some species of tardigrades, or water bears as the tiny aquatic creatures are also known, can survive in different environments often hostile or even fatal to most forms of life. For the first time, researchers describe a new mechanism that explains how some tardigrades can endure extreme dehydration without dying. They explored proteins that form a gel during cellular dehydration. This gel stiffens to support and protect the cells from mechanical stress that would otherwise kill them. These proteins have also been shown to work in insect cells and even show limited functionality in human cultured cells.

Tardigrades often draw attention to themselves, despite being so tiny. Their uncanny ability to survive in situations that would kill most organisms has captured the public’s imagination. One could easily imagine that by decoding their secrets, we could apply the knowledge to ourselves to make humans more resilient to extreme temperatures, pressures, and even dehydration. This is just science fiction for now, but nevertheless, researchers, also captivated by the microscopic creatures, seek to understand the mechanisms responsible for their robustness, as this could bring other benefits too.

“Although water is essential to all life we know of, some tardigrades can live without it potentially for decades. The trick is in how their cells deal with this stress during the process of dehydration,” said Associate Professor Takekazu Kunieda from the University of Tokyo’s Department of Biological Sciences. “It’s thought that as water leaves a cell, some kind of protein must help the cell maintain physical strength to avoid collapsing in on itself. After testing several different kinds, we have found that cytoplasmic-abundant heat soluble (CAHS) proteins, unique to tardigrades, are responsible for protecting their cells against dehydration.”

Recent research into CAHS proteins reveals that they can sense when the cell encapsulating them becomes dehydrated, and that’s when they kick into action. CAHS proteins form gel-like filaments as they dry out. These form networks that support the shape of the cell as it loses its water. The process is reversible, so as the tardigrade cells become rehydrated, the filaments recede at a rate that doesn’t cause undue stress on the cell. Interestingly though, the proteins exhibited the same kind of action even when isolated from tardigrade cells.

“Trying to see how CAHS proteins behaved in insect and human cells presented some interesting challenges,” said lead author Akihiro Tanaka, a graduate student in the lab. “For one thing, in order to visualize the proteins, we needed to stain them so they show up under our microscopes. However, the typical staining method requires solutions containing water, which obviously confounds any experiment where water concentration is a factor one seeks to control for. So we turned to a methanol-based solution to get around this problem.”

Research on mechanisms related to dry preservation of cells or organisms could have many future applications. Kunieda and his team hope that through this new knowledge, researchers might find ways to improve the preservation of cell materials and biomolecules in a dry state. This could extend the shelf life of materials used for research, medicines with short expiry dates, or maybe even whole organs needed for transplants.

“Everything about tardigrades is fascinating. The extreme range of environments some species can survive leads us to explore never-before-seen mechanisms and structures. For a biologist, this field is a gold mine,” said Kunieda. “I’ll never forget New Year’s Day 2019, when I received an email from Tomomi Nakano, another author of the paper. She had been working late trying to see the condensation of CAHS proteins and observed the first CAHS filament networks in human cultured cells. I was astonished at seeing such clearly defined microscopic images of these. It was the first time I had seen such a thing. It was a very happy new year indeed!”

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Newly identified fossil insect used 360-degree vision and sticky feet to find and snare its meals

With bulging eyes, an elongated mouth and feet that oozed resin, a fossil insect identified by Oregon State University research is so different from anything alive today that it needed to be placed in its own, extinct family.

George Poinar Jr., professor emeritus in the OSU College of Science, named the insect Palaeotanyrhina exophthalma in a paper published in BioOne Complete. Encased in 100-million-year-old amber from Burma, P. exophthalma is a member of the Hemiptera order -- a "true bug," Poinar said.

"It is a small predator that used its protruding eyes to locate insect prey," said Poinar, an international expert in using plant and animal life forms preserved in amber to learn about the biology and ecology of the distant past.

More than 80,000 species including cicadas, aphids, planthoppers, leafhoppers, bed bugs and shield bugs comprise the order of Hemiptera, an ancient Greek word meaning half-winged. True bugs' size varies widely, from as small as 1 millimeter to as large as 15 centimeters, but they all have a similar arrangement of sucking mouthparts.

P. exophthalma has a body length of just over 5 millimeters. It shares some features with members of the Reduvoidea superfamily, which includes the assassin bug and the kissing bug, but its long labium (lower mouth), its head shape and its forewing veins disqualify it from placement in any modern Reduvoidea family, Poinar said.

Thus he assigned it to a new, extinct family: Palaeotanyrhinidae.

"Its eyes provided a clear, 360-degree view of its habitat so it could see prey that might appear from any side," Poinar said.

It reminded Poinar of the phrase, "Big brother is always watching you," from George Orwell's novel "1984" in which security cameras followed individuals' every movement.

The other strange feature on this fossil is an extended sheath on the final leg segment of the front tarsus, he added.

"That sheath was filled with a resinous substance," Poinar said. "The sticky substance was produced by dermal glands and helped the insect grasp potential prey."

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Insects harbor over a thousand genes from microbes, which help them survive

Hundreds of millions of years ago, microbes and plants might have given insects an evolutionary advantage by passing genes to them through horizontal gene transfer. In a study published in the journal Cell on July 18, researchers report that more than 1,400 genes across 218 insect species, including butterflies and moths, that originated from bacteria, viruses, fungi, and plants. The study argues that these genes might have been essential for insect evolution by allowing them to develop beneficial traits in mating behavior, nutrition, growth, and adaptation to environmental changes.

Horizontal gene transfer (HGT) is fairly common between microbes. For example, bacteria use this mechanism to transmit antibiotic-resistance genes between species, but scientists more recently have been systematically looking at the phenomenon between insects and microbes or plants.

"Previous studies have shown that HGT may have contributed to insect biodiversity, but nobody knew how large a role it plays in this process," says senior author Xing-Xing Shen, an evolutionary biologist at Zhejiang University in Hangzhou, China. "Since there are a lot of high-quality insect genomes available for our analysis, I thought that now is a good time to systematically investigate how prevalent HGT is in insects."

Shen's team at Zhejiang University started this project in collaboration with Antonis Rokas, an evolutionary biologist at Vanderbilt University by gathering 218 high-quality insect genome samples representing 11 of 19 species-rich orders of insects. With the data, they were able to draw an evolutionary tree, identify out-of-place genes that are more commonly found in non-animal genomes, and examine what factors contribute to the fate of HGT in insects.

"There were HGT events everywhere we looked," says Shen. "However, we don't know whether these transfers of genes are beneficial to the insects, or even the functions for most of these genes," says Shen. He enlisted help from another expert -- Jianhua Huang, who studies insect gene functions at Zhejiang University.

"Shen walked into my office with a list of more than 1,400 genes, and we had to decide where to start," Huang says. The team decided to validate the function of the most prevalent foreign gene without known functions in insects: LOC105383139.

"This gene was horizontally introduced into nearly all moths and butterflies from a donor in the bacterial genus Listeria," they report in the study, meaning this gene has persisted in the genome since the time of moths' and butterflies' common ancestor more than 300 million years ago.

They decided to delete this ancient gene from diamondback moths, a pest affecting broccoli and cabbage, and observe what kind of functions it has. "Surprisingly, we saw those moths lacking this gene cannot produce many viable eggs," Huang says. "Then, we found that the gene influences the male courtship behavior."

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