Butterflies could lose spots as climate warms

Female Meadow Brown butterflies have fewer spots if they develop in warmer weather -- so climate change could make them less spotty, new research shows.

University of Exeter scientists found females that developed at 11°C had six spots on average, while those developing 15°C had just three.

The findings challenge long-held scientific views about why these butterflies have varying numbers of spots.

"Meadow Browns always have large 'eyespots' on their forewings, probably for startling predators," said Professor Richard ffrench-Constant, from the Centre for Ecology and Conservation on Exeter's Penryn Campus in Cornwall.

"They also have smaller spots on their hindwings, probably useful for camouflage when the butterfly is at rest.

"Our findings show that fewer of these hindwing spots appear when females experience higher temperatures during their pupal stage (in a chrysalis before emerging as a butterfly).

"This suggests the butterflies adapt their camouflage based on the conditions. For example, with fewer spots they may be harder to spot on dry, brown grass that would be more common in hot weather.

"We did not observe such a strong effect in males, possibly because their spots are important for sexual selection (attracting females)."

Since the classic work of biologist EB Ford, eyespot variation in the Meadow Brown butterfly has been used as an example of "genetic polymorphism" (the co-existence of multiple genetic forms in a single population).

However, the new study shows the eyespot variation is caused by thermal plasticity (the ability to react to changing temperatures).

"This is a family story for me, as my father collected butterflies for EB Ford here in Cornwall," Professor ffrench-Constant said.

"In the new study, we looked at current Cornish populations -- collecting males and females from the same field every day throughout the flight season -- and historical collections from Eton and Buckingham."

The researchers predict that spotting will decrease year on year as our climate warms.

Professor ffrench-Constant added: "This is an unexpected consequence of climate change. We tend to think about species moving north, rather than changing appearance."

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Butterfly-inspired films create vibrant colors while passively cooling objects

On a hot summer day, white clothing feels cooler than other colors due to reflecting -- not absorbing -- sunlight. Other colors like blue or black, will undergo a heating effect as they absorb light. To circumvent this heating effect in colored cooling films, researchers drew inspiration from nanostructures in butterfly wings.

The new films, which don't absorb any light, could be used on the outside of buildings, vehicles and equipment to reduce the energy needed for cooling while preserving vivid color properties.

"In buildings, large amounts of energy are used for cooling and ventilation, and running the air conditioner in electric cars can reduce the driving range by more than half," said research team leader Wanlin Wang from Shenzhen University in China. "Our cooling films could help advance energy sustainability and carbon neutrality."

In Optica, Optica Publishing Group's journal for high-impact research, the researchers show that the films they developed lower the temperature of colorful objects to about 2 °C below the ambient temperature. They also found that when left outside all day, the blue version of the films was approximately 26°C cooler than traditional blue car paint. This represents an annual energy savings of approximately 1377 MJ/m2 per year.

"With our new films, excellent cooling performance can be achieved, no matter the desired color, saturation or brightness," said Wang. "They could even be used on textiles to create clothes of any color that are comfortable in hot temperatures."

Inspired by nature

A car with blue paint appears blue because it absorbs yellow light and reflects blue light. The large amount of light that is absorbed heats the car. Morpho butterflies, however, produce their highly saturated blue color based on the nanostructure of their wings. The design of the cooling nanofilm mimics these structures to produce vibrant colors that don't absorb light like traditional paint.

To create their Morpho-inspired nanofilms, the researchers placed a disordered material (rough frosted glass) under a multilayer material made of titanium dioxide and aluminum dioxide. They then placed this structure on a silver layer that reflects all light, thus preventing the absorption of solar radiation and the heating associated with that absorption.

The film's color is determined by how components within its multilayered structure reflect light. To create blue, for example, the multilayer material is designed to reflect yellow light in a very narrow range of angles while the disordered structure diffuses the blue light across a broad area.

Although this type of passive photonic thermal management has been accomplished before, it has only been used with white or clear objects because it is difficult to maintain a wide viewing angle and high color saturation.

Passive cooling of colorful objects

"Thanks to the layered structure we developed, we were able to extend the passive cooling method from colorless objects to colorful ones while preserving color performance," said Wang. "In other words, our blue film looks blue across a large range of viewing angles and doesn't heat up because it reflects all the light. In addition, high saturation and brightness can be achieved by optimizing the structure."

To test the new technology, the researchers created blue, yellow and colorless films, which they placed outdoors at Shenzhen University, on surfaces such as roofs, cars, cloth and cell phones, from 9 a.m. to 4 p.m. in both winter and summer. Using thermocouple sensors and infrared cameras to measure temperature, they found that the cooling films were more than about 15 ? cooler than the surfaces they were placed on in the winter and about 35 ? cooler in the summer.

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Scientists caught Hofstadter's butterfly in one of the most ancient materials on Earth

Researchers in the National Graphene Institute (NGI) at The University of Manchester have revisited one of the most ancient materials on Earth -- graphite, and discovered new physics that has eluded the field for decades.

Despite being made entirely of layers of carbon atoms arranged in a honeycomb pattern, natural graphite is not as simple as one may think. The manner in which these atomic layers stack on top of one another can result in different types of graphite, characterised by different stacking order of consecutive atomic planes. The majority of naturally appearing graphite has hexagonal stacking, making it one of the most "ordinary" materials on Earth. The structure of graphite crystal is a repetitive pattern. This pattern gets disrupted at the surface of the crystal and leads to what's called 'surface states', which are like waves that slowly fade away as you go deeper into the crystal. But how surface states can be tuned in graphite, was not well understood yet.

Van der Waals technology and twistronics (stacking two 2D crystals at a twist angle to tune the properties of the resulting structure to a great extent, because of moiré pattern formed at their interface) are the two leading fields in 2D materials research. Now, the team of NGI researchers, led by Prof. Artem Mishchenko, employs moiré pattern to tune the surface states of graphite, reminiscent of a kaleidoscope with everchanging pictures as one rotates the lens, revealing the extraordinary new physics behind graphite.

In particular, Prof. Mishchenko expanded twistronics technique to three-dimensional graphite and found that moiré potential does not just modify the surface states of graphite, but also affects the electronic spectrum of the entire bulk of graphite crystal. Much like the well-known story of The Princess and The Pea, the princess felt the pea right through the twenty mattresses and the twenty eider-down beds. In the case of graphite, the moiré potential at an aligned interface could penetrate through more than 40 atomic graphitic layers.

This research, published in the latest issue of Nature, studied the effects of moiré patterns in bulk hexagonal graphite generated by crystallographic alignment with hexagonal boron nitride. The most fascinating result is the observation of a 2.5-dimensional mixing of the surface and bulk states in graphite, which manifests itself in a new type of fractal quantum Hall effect -- a 2.5D Hofstadter's butterfly.

Prof. Artem Mishchenko at The University of Manchester, who has already discovered the 2.5-dimensional quantum Hall effect in graphite said: "Graphite gave rise to the celebrated graphene, but people normally are not interested in this 'old' material. And now, even with our accumulated knowledge on graphite of different stacking and alignment orders in the past years, we still found graphite a very attractive system -- so much yet to be explored." Ciaran Mullan, one of the leading authors of the paper, added: "Our work opens up new possibilities for controlling electronic properties by twistronics not only in 2D but also in 3D materials."

Prof. Vladimir Fal'ko, Director of the National Graphene Institute and theoretical physicist at the Department of Physics and Astronomy, added: "The unusual 2.5D quantum Hall effect in graphite arises as the interplay between two quantum physics textbook phenomena -- Landau quantisation in strong magnetic fields and quantum confinement, leading to yet another new type of quantum effect."

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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.

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Butterflies on the decline

Research shows that the numbers of butterflies in meadows and pastures of Europe are in a continuous decline. A new EU regulation aims to stop this trend.

Grassland butterflies will soon play an even greater role in EU nature conservation legislation. Based on the occurrences and population trends of butterflies, the member states are supposed to document the progress they have made in implementing the planned "Nature Restoration Law." The Butterfly Grassland Indicator, recently calculated for the eighth time by European foundation "Butterfly Conservation Europe," is to be used for this. This analysis, which also includes data and expertise from many volunteers in Germany -- coordinated by experts from the Helmholtz Centre for Environmental Research (UFZ) in Halle -- shows an urgent need for action. This is because the situation of grassland butterflies in Europe has deteriorated considerably since the first calculations in 1990.

The diagnosis sounds worrying: More than 80% of habitats in the EU are currently considered vulnerable. This has negative consequences on their functional capability and thus the services they provide for humans. In order to counter this, the European Commission has proposed a new set of rules. This "Nature Restoration Law" is one of the key elements of the EU Biodiversity Strategy 2030 to be published this May. It defines binding targets for the entire EU for the renaturation of various ecosystems. Two years after the regulation enters into force, member states must submit plans on how they intend to meet these targets. They must also document the success of their measures.

However, the latter is not so easy. So far, there are only a few indicators that can reliably show the state of biodiversity. For most animal and plant groups, there is a lack of comparable data across Europe from which to assess the development of populations. The few exceptions include birds, bats, and butterflies.

"Butterflies in particular are ideal bioindicators," says agricultural ecologist Prof. Dr Josef Settele from the UFZ. This is because these insects occur in a wide range of habitats and react sensitively to environmental changes. With their specific requirements, they are often representative of many other insects. Finally, they are eye-catching, attractive, and popular. It is thus relatively easy to motivate volunteers to take part in scientifically oriented butterfly counts.

Such actions are becoming increasingly popular. For example, in 2005 the UFZ and the Gesellschaft für Schmetterlingsschutz (GfS) launched a citizen science project called "Tagfaltermonitoring Deutschland" (Butterfly Monitoring Germany) in which anyone interested can participate. Since then, butterfly enthusiasts from all over Germany have been walking fixed routes from spring to autumn to record the number of individuals and species they have seen. Similar monitoring programmes now exist in most other European countries. "Around 5,000 volunteers spread all over Europe are now taking part -- all following the same protocol," says Settele.

The data are collected and analysed in the central "European Butterfly Monitoring Scheme" (eBMS) database, managed by UKCEH and mirrored at UFZ and the Dutch "Vlinderstichting." In this way, the population development of individual species can then be tracked. Common trends for the inhabitants of certain habitats can also be identified.

This is precisely the idea behind the Butterfly Grassland Indicator, which is based on the population trends of 17 typical species of meadows and pastures. If the positive and negative trends in these species roughly balance each other out, the indicator remains at the same level. If more species decline than increase in the same period, the value decreases -- and vice versa. Lower values thus indicate greater problems among grassland dwellers.

The latest results of these calculations, which include data from 1990 to 2020, therefore do not bode well. The analysis, which was also co-financed by the EU project SPRING (Strengthening Pollinator Recovery through Indicators and monitoring) coordinated by the UFZ, shows only one winner: In the 27 memberstates of the EU, only the Orange Tip (Anthocharis cardamines) displayed a moderate increase. Three species are stable: the Large Skipper (Ochlodes sylvanus), the Common Copper (Lycaena phlaeas), and the Meadow Brown (Maniola jurtina). Five species -- from the Common Blue (Polyommatus icarus) to the Wall Brown (Lasiommata megera) -- are showing declining populations. "The biggest loser in recent years has been the large blue (Phengaris arion), which for example has disappeared completely in the Netherlands," says Settele. For the remaining species of the 17 grassland inhabitants studied, there is either no clear trend or too little data.

The picture becomes even less favourable if we look not only at the EU but rather at Europe as a whole. Then there are no species on the rise and only three are stable. Six show a moderate and one even a strong decline.

In view of these developments, it is not surprising that the grassland indicator is now at a considerably lower level than before. In the last 10 years alone, the calculated value for the EU has fallen by 32% -- and that for Europe as a whole by as much as 36%. The crisis of the grassland dwellers has apparently already taken hold of the entire continent. This is becoming increasingly more evident the more information is provided by the volunteer butterfly counters from different countries. "The declines are not confined to north-western Europe," says Chris van Swaay of Butterfly Conservation Europe. "However, some species in the South and East are doing much better."

He and his colleagues attribute the dwindling butterfly occurrences mainly to changes in agriculture. In north-western Europe, for example, the over-intensive use of meadows and pastures has a particularly unfavourable effect. The heavy use of fertilisers often also pollutes adjacent protected areas with excessive amounts of nitrogen. In the rest of Europe, the main problem is the complete abandonment of cultivation. That's because grassland butterflies also cope poorly with this.

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Family tree of 'boring' butterflies reveals they're anything but

Walk a short distance through the Amazon Rainforest, and you might witness what look like dead leaves launch from the ground and fly off into the understory. These masters of disguise are euptychiines, one of the most diverse and least understood groups of butterflies in the American Tropics.

There are as many as 100 co-occurring euptychiine species in the rainforests of Peru and Brazil, but even the most seasoned butterfly experts have a hard time telling them apart.

"They're one of the groups that often get called 'brown, boring butterflies,'" said André Freitas, a biology professor at the State University of Campinas in Brazil. "They aren't very attractive to collectors or researchers, and even distantly related species can look very similar. The early naturalists had no way to accurately classify them."

Freitas is a co-author on a new study that adds some much-needed definition to what has remained, up until now, a black hole of butterfly diversity. The German entomologist Jacob Hübner was the first to describe the group in the early 1800s, when he lumped the few species then known into a handful genera based on similar appearance.

Using DNA, Freitas and his colleagues show there are at least 70 Euptychiina genera, containing more than 500 species. Their results also suggest there are at least 130 unnamed species in the group awaiting scientific description.

The study is the result of a project more than a decade in the making, initially conceived by Keith Willmott, director of the McGuire Center for Lepidoptera and Biodiversity at the Florida Museum of Natural History. In 2009, Willmott reached out to Freitas and other researchers who'd taken a stab at individually sorting through euptychiine butterflies piecemeal and proposed they instead combine their efforts.

Before researchers could make heads or tails of euptychiine diversity, they first needed a sense of just how many groups there were and how they were related to each other.

"The way people would typically work on this kind of problem would be to divide and conquer, but that doesn't work for euptychiines, because there are very few unifying features among species that you can use to define groups," Willmott said.

Instead, a coalition of international researchers focused on studying as many euptychiine species as they could lay their hands on. They examined more than 60,000 specimens from museums in Europe and North and South America and collected euptychiine butterflies throughout their range, from the foothills of the Andes in Ecuador to the Atlantic Forest in Southeastern Brazil.

In the process, they discovered more than 100 new species, many of which were hiding in plain sight, concealed by their close resemblance to each other.

"A recent example is a large butterfly that used to be known as Pseudodebis celia from western Ecuador, which turned out to be four separate species," Willmott said. "These are big butterflies. It's hard to imagine these kinds of species are still escaping detection."

Not all euptychiines have evolved to blend in. Several species have bright blue scales or blazing orange eyespots, which might seem like it'd make them easy to classify. But closer inspection reveals these color patterns can be deceptive as well. Results of the study's genetic analysis show, for example, that multiple, Euptychiines have transformed their wings into blue frescoes, making them appear superficially similar.

Mimicry is often the primary suspect when unrelated butterflies have a similar appearance. Predators learn to avoid species with toxic, bitter-tasting compounds, like Monarchs (Danaus plexippus). With a little false advertising, species that lack these compounds can still deter predators by copying the colors and patterns of genuinely toxic butterflies.

But according to Willmott, this likely isn't the case for euptychiines. "As far as we know, they're not unpalatable or protected against predators in any way. It looks like mimicry, but there's really no basis for it. It's a fascinating mystery that needs study."

Blue euptychiines can play further tricks on butterfly experts -- sometimes, the color is only present in some individuals of a given species.

"In most cases, the males are colorful, and the females are brown," said Marianne Espelend, a curator at the Leibniz Institute for the Analysis of Biodiversity and lead author on the study.

This mismatch has led to several cases of mistaken identity. A brown species from French Guiana described in 2012 was later determined to be the incognito female half of a well-known species discovered a century earlier. This triggered inspection of other blue species, and discovery of similar problems.

The new classification provided by this study will help researchers pin down the exact identity of familiar euptychiines and shorten the long queue of species in the group that have yet to be given a scientific name.

It also sets the stage for scientific forays into other aspects of euptychiine biology that experts are just now beginning to understand, said Freitas, reciting a litany of unknowns that can now be thoroughly investigated.

"We know that several species have scales that release scents to attract females, but we have no idea what types of chemicals are involved; the males of some species make an audible clicking sound, but we don't know how they do it; and I can count on my hand the number of times I've been able to find euptychiine caterpillars in the wild, of which we know very little."

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Bigger flowers, greater rewards: Plants adapt to climate disruptions to lure pollinators

There's been a well-documented shift toward earlier springtime flowering in many plants as the world warms. The trend alarms biologists because it has the potential to disrupt carefully choreographed interactions between plants and the creatures -- butterflies, bees, birds, bats and others -- that pollinate them.

But much less attention has been paid to changes in other floral traits, such as flower size, that can also affect plant-pollinator interactions, at a time when many insect pollinators are in global decline.

In a study published online in the journal Evolution Letters, two University of Michigan biologists and a University of Georgia colleague show that wild populations of the common morning glory in the southeastern United States increased the size of their flowers between 2003 and 2012.

Increased flower size suggests a greater investment by the plants in pollinator attraction, according to the researchers. The changes were most pronounced at more northern latitudes, in line with a broad range of previous work showing that northern plant populations tend to show more dramatic evolutionary responses to climate change.

A shift to earlier flowering was also observed among those morning glory populations. In addition, there were tantalizing indications that the plants have increased their investment in floral rewards -- the nectar and pollen obtained by the bees, syrphid flies and wasps that pollinate the white, pink and blue morning glory flowers.

"There is a major gap in our understanding of how traits that are crucial for plant-pollinator interactions may be evolving over time as a response to a changing climate," said study lead author Sasha Bishop, a doctoral student in the U-M Department of Ecology and Evolutionary Biology.

"We show that -- in addition to well-documented shifts to earlier flowering -- floral architecture and rewards can also play significant roles in the evolutionary response to contemporary environmental change."

The common morning glory is an annual weedy vine found across the eastern, midwestern and southern United States. It is frequently seen along roadsides and crop fields.

The U-M-led study used a "resurrection" approach that involved germinating morning glory seeds collected from the edges of agricultural soy and corn fields in Tennessee, North Carolina and South Carolina in two years: 2003 and 2012.

During that nine-year span, the region experienced rising temperatures -- particularly rising minimum and nighttime temperatures -- and an increase in the number of extreme rainfall events interspersed with more extreme drought.

To look for changes in floral morphology, the researchers planted field-collected seeds from both years in a greenhouse at U-M's Matthaei Botanical Gardens. When the flowers bloomed, various floral traits were measured with digital calipers.

Measurements showed that morning glory corollas became significantly wider during the nine-year interval -- 4.5 centimeters (1.8 inches) in diameter in 2003 and 4.8 centimeters (1.9 inches) in 2012, and the change in corolla width was greatest in populations at more northern latitudes. The petals of a flower are collectively known as the corolla.

The study also revealed a shift to earlier flowering times between 2003 and 2012, driven primarily by populations at more northern latitudes. The start of flowering occurred an average of four days earlier for the plants grown from seeds collected in 2012.

Interestingly, the researchers also observed a latitude-influenced trend toward greater investment in floral rewards (pollen and nectar) over time. On average, morning glory flowers grown from 2012-collected seeds produced more pollen grains and more nectar sucrose than the flowers from the 2003-collected seeds.

However, the pollen and nectar analyses involved only four populations of morning glory plants. Due to the low number of populations examined, the floral rewards findings were not included in a statistical test to look for evidence that adaptation through natural selection is occurring in the plants.

"Nonetheless, it appears likely that there is a temporal increase in investment in pollinator attraction and that this result is driven by populations at northern latitudes," said study senior author Regina Baucom, an associate professor in the U-M Department of Ecology and Evolutionary Biology.

The study found no evidence that morning glories are increasing the rate at which they self-pollinate. Evidence from some previous studies pointed to increased "selfing" as a possible response to climate change and/or pollinator declines associated with land-use change.

"This is the first article to use the resurrection approach to examine the potential that traits responsible for plant-pollinator interactions may be evolving over time, concomitant to decreases in pollinator abundance and dramatic environmental changes due to changing climate and land-use regimes," Bishop said.

Fifteen morning glory populations were included in the resurrection experiment looking at changes in floral morphology. Twenty-three populations were included in the study of earlier springtime flowering. In total, 2,836 flowers were measured from 456 plants.

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A butterfly flaps its wings and scientists make jewelry

The further out in time, the more unreliable a weather forecast. That's because small variations in initial weather conditions can completely change the entire system, making it unpredictable. Put another way, in the "butterfly effect," an insect can flap its wings and create a microscopic change in initial conditions that leads to a hurricane halfway around the world.

This chaos is seen everywhere, from weather to labor markets to brain dynamics. And now, in the journal Chaos, by AIP Publishing, researchers from the University of Calabria explored how to turn the twisting, fractal structures behind the science into jewelry with 3D printing.

The jewelry shapes are based on the Chua circuit, a simple electronic system that was the first physical, mathematical, and experimental proof of chaos. Instead of an ordinary circuit, which produces an oscillating current, Chua's circuit results in oscillations that never repeat.

"These chaotic configurations, called strange attractors, are complex structures that had never been observed before," said author Eleonora Bilotta. "The depictions of such structures are strikingly beautiful, continually shifting when the point of view is changing. Jewelry seemed to be the best way to interpret the beauty of chaotic shapes."

At first, the team tried to employ goldsmiths to create prototypes of the twisting, arcing patterns. But the chaotic forms proved too difficult to manufacture with traditional methods. In contrast, additive printing allows for the necessary detail and structure. By 3D-printing the jewelry, the team created a counter-mold for a goldsmith to use as a cast.

"Seeing the chaotic shapes transformed into real, polished, shiny, physical jewelry was a great pleasure for the whole team. Touching and wearing them was also extremely exciting," said Bilotta. "We think it is the same joy that a scientist feels when her theory takes form, or when an artist finishes a painting."

The jewelry can also be used as an educational tool, providing students the ability to develop their scientific knowledge and artistic creativity. By building Chua's circuit, they can manipulate chaos and discover the extreme sensitivity to initial conditions. While designing the jewelry before sending it to be printed, they can tweak the parameters to generate different shapes according to personal taste.

Read more at Science Daily

The dark cost of being toxic

An international research team including scientists from the Max Planck Institute for Chemical Ecology in Jena has discovered that the striking orange and black wings of monarch butterflies not only send the message to predators that these butterflies are highly toxic, but that the storage of toxins and development of the colourful wings come at a cost to the butterfly's body. The team reared monarch caterpillars on their milkweed food plants that had different levels of toxins. Monarchs that had ingested high levels of toxins from their food plants as caterpillars, experienced high levels of oxidative damage after storing these toxins in their bodies, and were less conspicuous in their coloration. The study demonstrated experimentally that the storing of toxins is costly for insects that are highly specialized on their food plants.

Monarch butterflies (Danaus plexippus) feed on milkweeds of the genus Asclepias when they are caterpillars, storing the plants' cardenolide heart poisons in their bodies for their own defence. The combination of the toxins with the striking orange and black wings of the monarch is called aposematism (derived from the Greek terms apo = away and sema = signal). Hannah Rowland head of the Max Planck Research Group on Predators and Toxic Prey at the Max Planck Institute for Chemical Ecology explains: "aposematism works because predators learn that eye-catching prey are best avoided. Predators learn faster when the visual signal is always the same. Bright orange means "`'don't eat me'. But other scientists and I have repeatedly found that aposematic animals can have varying degrees of warning signal strength, and we wondered what about pale orange, or deep orange? What does this mean, and what causes the difference?"

Rowland, together with her colleague Jonathan Blount from the University of Exeter, along with their international team of scientists, tested whether the storage of the plant's toxins is costly to the butterfly's body condition. Specifically, whether the storage of toxins causes oxidative stress, whichhappens when antioxidant levels are low. Because antioxidants can be used to make colourful pigments, they tested if the amount of toxins in the monarch is related to their conspicuousness and their oxidative state.

The researchers reared monarch caterpillars on four different milkweeds of the genus Asclepias that have different toxin levels. With this, they were able to manipulate the amount of toxins ingested to subsequently measure concentrations of cardenolides, determine oxidative state, and compare the resulting wing coloration.

"Monarch butterflies that sequestered higher concentrations of cardenolides experienced higher levels of oxidative damage than those that sequestered lower concentrations. Our results are among the first to show a potential physiological mechanism of oxidative damage as a cost of sequestration for these insects," says Hannah Rowland. The scientists also found that the colour of the wings of male monarchs depended on how much cardenolides they sequestered, and how much oxidative damage this had resulted in. Males with the highest levels of oxidative damage showed decreasing colour intensity with increased toxin uptake, while males with the least oxidative damage were the most toxic and colour intense.

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Transparency in butterflies, from A-Z: It’s more of a superpower than we thought

Like invisibility in legends, transparency in nature is a powerful tool. Most transparent animals live in the ocean, where a close visual match with the water renders them almost invisible to predators.

On land, transparency is rare and difficult to achieve, but some butterflies and moths (Lepidoptera) do have transparent wings. And a new study indicates transparency can serve not only to camouflage them, but in other cases to signal and warn predators, "Don't eat me! I'm toxic."

This flexible weapon for self-defense is one of many findings from a multiyear study spanning the physics, biology, ecology, and evolution of transparency in Lepidoptera conducted by several groups, including the lab of Nipam Patel, director of the Marine Biological Laboratory (MBL).

"This is one of those interdisciplinary studies you dream about, where you want to understand [a biological structure] from its physics to its development and ecology," says Patel of the international study, which began as a project in the MBL Embryology course and ended up being funded by the Human Frontier Science Program. Ph.D. candidate Aaron Pomerantz in Patel's lab is also on the team.

Mimicry for Self-Defense

The group's latest paper adds a unique perspective on Lepidoptera self-defense. In some species, vivid wing coloration indicates the presence of chemical defenses that make the butterfly unpalatable or toxic, and predators learn to avoid them. Accordingly, palatable species can evolve to mimic the toxic ones, so predators leave them alone, too. In addition, multiple unpalatable species may converge in their warning colorations, thereby sharing in the benefits of the warning coloration process. Large "mimicry rings" can even form containing both toxic and nontoxic species, all displaying strikingly similar patterns and color combinations.

"The most amazing place to see this is the Amazon," Patel says. "You'll find a group of species that are distantly related to each other, yet they've all converged on a similar wing pattern."

Surprisingly, mimicry rings have also been found among clear-wing species in the Amazon. "So we asked, 'Wait, why would a species be transparent and unpalatable at the same time?'" Patel says. And, structurally, how would a clear-wing species accomplish that trick?

The team looked at the optical and structural properties of transparent butterfly wings within mimicry rings to see if they were convergent, and found in some rings, they were.

"In one transparency ring we studied (see photo 1, middle row), the key unpalatable butterfly doesn't have an anti-glare coating on its transparent wing, so in sunlight, it's really easy to see," Patel says. "It may be signaling a warning pattern to predators when it's in bright sun, and it's camouflaged when in shadows. So it kind of cheats: it has the best of both worlds."

Previously, the team reported on the developmental origins of transparency in a clear-wing species, Greta oto. They also compared wing transparency across 123 Lepidoptera species for its structural basis, optical properties, and biological relevance in relation to concealment, thermoregulation, and protection against UV. Those results showed a wide diversity of solutions to achieve transparency, suggesting that transparency has likely evolved multiple times independently.

Approaching transparency from multiple disciplines brought emergent knowledge and interesting new questions, Patel said. "Now that we've identified different Lepidoptera groups that have found different ways to achieve transparency, we can ask, how did they actually do this? Or, alternatively, if two very distant lineages have come up with the same solution for transparency, did they solve the problem in the same way?"

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Map of transparent butterflies highlights biodiversity hotspot in the Andes Mountains

With over a million known species, insects are by far the most diverse group of organisms on Earth, with conservative estimates indicating there are millions more waiting to be found. But extinction due to human pressures may be outpacing the rate of discovery, with species disappearing before researchers even knew they existed.

To conserve these species, scientists must first know where they are. While the distributions of some plant and animal groups have been extensively mapped, comparatively little is known regarding the whereabouts of the world's insects.

In a new study, researchers created the most detailed distribution map to date of butterflies in the American tropics, showing that areas of highest diversity coincide with regions most threatened by deforestation and development. The study specifically focused on Ithomiini, or glasswing butterflies, a large group with nearly 400 species that occur throughout much of Central and South America. Their ubiquity may make them a good indicator for the fate of other insects in the region.

"If we want to understand the diversity of insects in general, then one approach is to concentrate on groups that likely reflect the diversity of all insects and for which we have good knowledge, like butterflies," said study co-author Keith Willmott, curator and director of the Florida Museum of Natural History's McGuire Center for Lepidoptera and Biodiversity.

Mimicry both helps and hinders glasswings

Glasswing butterflies get their namesake from their unusual, transparent wings marked with colorful spots of alternating hues and patterns. As with many other butterfly species, such as monarchs, these markings serve as a warning. Male glasswing butterflies feed on the nectar and tissue of poisonous plants, concentrating the toxins in their abdomen and passing them on to females when mating. These toxins, a type of alkaloid, give the butterflies and their eggs a bitter taste that makes them unpalatable.

But would-be predators aren't born innately knowing not to eat these butterflies, instead learning through trial and error. As a result, many glasswing species have evolved similar wing patterns that give them strength in numbers.

"Since different species share the same warning color patterns, they share the overall cost per species of educating predators to avoid them," Willmott said.

This type of resemblance, called Müllerian mimicry, has helped glasswing butterflies survive and diversify in the varied habitats of the tropics, but it also comes at a cost. While this strategy is effective when all species resembling one another are thriving, the extinction of any one species could jeopardize the survival of others, Willmott explained. "This is particularly true if one of the more common species goes extinct, because all the others lose the benefit they gained from being involved in Müllerian mimicry with those butterflies."

Glasswing butterflies are most diverse and most vulnerable at high elevations

Willmott and his colleagues have spent the last several decades trekking across mountains and forests in search of glasswings, describing new species and documenting their natural history along the way. By combining the data they've collected over the years with information gleaned from specimens in more than 60 museums and private collections, the researchers compiled nearly 30,000 distribution records. They used this extensive dataset to map the diversity of glasswings and the interactions between lookalike species throughout the American tropics.

Their results indicate glasswings are highly diverse in particular parts of their range, including the Amazon River basin, where their transparent wings help them blend in against the backdrop of forest gloom. But the majority of species cluster together in mountainous biodiversity hotspots. The eastern slopes of the Andes Mountains contained the top 5% of glasswing diversity, while secondary hotspots included the highlands of Central America and the Atlantic coastal forest of Brazil.

While large tracts of the Amazon rainforest remain relatively undisturbed, glasswing diversity in the tropical Andes frequently overlapped with areas at the highest risk of habitat loss due to land conversion for agriculture. This was especially true for species with restricted distributions, highlighting the pressing need for conservation efforts in these areas.

Mountainous regions create a variety of small, localized environments as they climb in elevation. The relatively young Andes, which are among the world's highest mountains, support a correspondingly large number of species. The differences in topography, temperature and rainfall also make the Andes an ideal place to grow a variety of crops. "At the moment, loss of habitat is the most significant threat," Willmott said. "It is just an unfortunate coincidence that areas that are good for people to live are also areas that support high animal and plant diversity."

Lead author Maël Doré, a doctoral student at the National Museum of Natural History in Paris, also worries that climate change may further limit the range of already restricted species on the slopes of tropical mountains. As temperatures increase, species may cope by shifting their distributions to higher elevations, but whether glasswing communities will move fast enough to keep up with climate change is uncertain.

Far from the Andes, the lower and older mountains along the Brazilian Atlantic coast are home to a number of rare and endemic glasswing species, which also face threats from habitat destruction. "This region has experienced almost five centuries of human occupation, but it was also here that pioneering initiatives to protect Neotropical butterflies and their habitats were born almost 100 years ago," said co-author André Freitas, a professor at the Universidade de Campinas in São Paulo, Brazil.

Still, Willmott and his colleagues remain optimistic. With a detailed map of where butterflies occur, conservation efforts can be directed to preserve environments and communities under threat, as well as those that are still untouched by humans.

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New alpine moth solves 180-year-old mystery

Butterflies and moths (order Lepidoptera) are one of the most diverse animal groups. To date, scientists have found as many as 5,000 species from the Alps alone. Having been a place of intensive research interest for 250 years, it is considered quite a sensation if a previously unknown species is discovered from the mountain range these days. This was the case when a Swiss-Austrian team of researchers described a new species of alpine moth in the open-access, peer-reviewed journal Alpine Entomology, solving a 180-year-old mystery.

Decades of research work

Initially, the team -- Jürg Schmid, a full-time dentist, author and passionate butterfly and moth researcher from Switzerland, and Peter Huemer, head of the natural science collections of the Tyrolean State Museums in Innsbruck and author of more than 400 publications, needed a lot of patience.

Almost thirty years ago, in the 1990s, the two researchers independently discovered the same moth species. While they found it was similar to a moth of the leaf-roller family Tortricidae and commonly named as Dichrorampha montanana which had been known to science since 1843, it was also clearly different. Wing pattern and internal morphology of genitalia structures supported a two-species hypothesis. Moreover, the two were found at the same time in the same places -- a further indication that they belong to separate species. Extensive genetic investigations later confirmed this hypothesis, but the journey of presenting a new species to science was far from over.

The Hidden Alpine Moth

To "baptise" a new species and give it its own name, scientists first have to check that it hasn't already been named. This prevents the same species from having two different names, and essentially means looking at descriptions of similar species and comparing the new one against them to prove it is indeed unknown to science. In the case of this new moth, there were six potentially applicable older names that had to be ruled out before it could be named as new.

Intensive and time-consuming research of original specimens in the nature museums of Paris, Berlin, Frankfurt and London eventually led to the finding that all six ancient names actually referred to one and the same species -- Dichrorampha alpestrana, which has been known since 1843 and had to be adopted as the valid older name for Dichrorampha montanana as having been described a couple of months earlier. Similarly, all other available names proved to belong to Dichrorampha alpestrana. The species discovered by Schmid and Huemer, however, was different, not yet named, and could finally be described as new to science. The authors chose to name it Dichrorampha velata -- the Latin species name means "veiled" or "hidden," pointing to the complicated story behind its discovery.

Lots of unanswered questions

The Hidden Alpine Moth is a striking species with a wingspan of up to 16 mm and a characteristic olive-brown color of the forewings with silvery lines. It belongs to a group of mainly diurnal moths and is particularly common locally in colorful mountain flower meadows. For now, we know that its distribution extends at least from Salzburg and Tyrol through southern Switzerland and the Jura to the French and Italian Alps, with isolated finds known from the Black Forest in Germany, but the researchers believe it might have a wider range in Central Europe.

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