European butterfly evolution, new research


This video says about itself:

Some old footage of butterflies from Germany and Sweden.

Melitaea athalia, Plebejus idas, Araschnia levana and Cabera pusaria.

From ScienceDaily:

Scientists unravel the evolution and relationships for all European butterflies

June 15, 2020

For the first time, a complete time-calibrated phylogeny for a large group of invertebrates is published for an entire continent.

In a recent research paper in the open-access, peer-reviewed academic journal ZooKeys, a German-Swedish team of scientists provide a diagrammatic hypothesis of the relationships and evolutionary history for all 496 European species of butterflies currently in existence. Their study provides an important tool for evolutionary and ecological research, meant for the use of insect and ecosystem conservation.

In order to analyse the ancestral relationships and history of evolutionary divergence of all European butterflies currently inhabiting the Old continent, the team led by Martin Wiemers — affiliated with both the Senckenberg German Entomological Institute and the Helmholtz Centre for Environmental Research — UFZ, mainly used molecular data from already published sources available from NCBI GenBank, but also contributed many new sequences, some from very local endemics for which no molecular data had previously been available.

Butterflies, the spectacular members of the superfamily Papilionoidea, are seen as an important proponent for nature conservation, as they present an excellent indicator group of species, meaning they are capable of inferring the environmental conditions of a particular habitat. All in all, if the local populations of butterflies are thriving, so is their habitat.

Furthermore, butterflies are pollinating insects, which are of particular importance for the survival of humans. There is no doubt they have every right to be recognised as a flagship invertebrate group for conservation.

In recent times, there has been a steady increase in the molecular data available for research, however, those would have been only used for studies restricted either to a selected subset of species, or to small geographic areas. Even though a complete phylogeny of European butterflies was published in 2019, also co-authored by Wiemers, it was not based on a global backbone phylogeny and, therefore, was also not time-calibrated.

In their paper, Wiemers and his team point out that phylogenies are increasingly used across diverse areas of macroecological research, such as studies on large-scale diversity patterns, disentangling historical and contemporary processes, latitudinal diversity gradients or improving species-area relationships. Therefore, this new phylogeny is supposed to help advance further similar ecological research.

Pesticides threaten monarch butterflies


This 2014 video from the USA says about itself:

Researchers Suggest Monsanto Behind 90 Percent Drop in Monarch Butterfly Population

The monarch butterfly population has been reduced by ninety percent over the past twenty years. In terms related to the human population that’s the equivalent of losing every human in the United States except for those in Florida and Ohio.

Monsanto is now Bayer. Different name, same pesticides.

From the University of Nevada, Reno in the USA:

Milkweed, only food source for monarch caterpillars, ubiquitously contaminated

Harmful pesticides found in Western Monarch breeding ground

June 8, 2020

New evidence identifies 64 pesticide residues in milkweed, the main food for monarch butterflies in the west. Milkweed samples from all of the locations studied in California’s Central Valley were contaminated with pesticides, sometimes at levels harmful to monarchs and other insects.

The study raises alarms for remaining western monarchs, a population already at a precariously small size. Over the last few decades their overwintering numbers have plummeted to less than 1% of the population size than in the 1980s — which is a critically low level.

Monarch toxicity data is only available for four of the 64 pesticides found, and even with this limited data, 32% of the samples contained pesticide levels known to be lethal to monarchs, according to a study released today in Frontiers in Ecology and Evolution.

“We expected to find some pesticides in these plants, but we were rather surprised by the depth and extent of the contamination,” said Matt Forister, a butterfly expert, biology professor at the University of Nevada, Reno and co-author of the paper. “From roadsides, from yards, from wildlife refuges, even from plants bought at stores — doesn’t matter from where — it’s all loaded with chemicals. We have previously suggested that pesticides are involved in the decline of low elevation butterflies in California, but the ubiquity and diversity of pesticides we found in these milkweeds was a surprise.”

Milkweed was chosen as the focus of this study because it the only food source for larval monarch butterflies in the West, and thus critical for their survival.

“We collected leaf samples from milkweed plants throughout the Central Valley and sent them to be screened for pesticides,” Chris Halsch, lead author of the paper and a doctoral student in the University’s Ecology, Evolution, and Conservation Biology program, said. “This study is the first necessary step for understanding what butterflies are actually encountering. Now we can use these data to design experiments to test hypotheses about the relative importance of pesticide use and other stressors such as climate change on local butterflies.”

While this is only a first look at the possible risks these pesticides pose to western monarchs, the findings indicate the troubling reality that key breeding grounds for western monarchs are contaminated with pesticides at harmful levels.

“One might expect to see sad looking, droopy plants that are full of pesticides, but they are all big beautiful looking plants, with the pesticides hiding in plain sight,” Forister, who has been a professor int he University’s College of Science since 2008, said.

Western monarchs are celebrated throughout the western states and especially along the California coast where large congregations overwinter in groves of trees. Population declines also have been documented in the breeding grounds. Areas of inland California, including the Central Valley, offer important monarch breeding habitat throughout the spring and summer, including being the home to the very first spring generation which will continue the migration inland to eventually populate all western states and even southern British Columbia.

Declines in the population of western monarch butterflies have been linked with various stressors, including habitat loss and degradation, pesticide use, and climate change, among others. While pesticide use has been associated with declines, previous studies had not attempted to quantify the residues that butterflies can encounter on the western landscape.

The study’s findings paint a harsh picture for western monarchs, with the 64 different pesticides identified in milkweed. Out of a possible 262 chemicals screened, there was an average of nine types of individual pesticides per sample and as many as 25. Agricultural and retail samples generally had more residues than wildlife refuges and urban areas, but no area was entirely free from contamination. Certain pesticides were present across all landscapes, with five pesticides appearing more than 80% of the time. Chlorantraniliprole, the second most abundant compound, was found at lethal concentrations to Monarchs in 25% of all samples.

Understanding of pesticide toxicity to the monarch is limited, and is based on previously reported lab experiments. Thus we have much to learn about the concentrations encountered in field, but these new results raise concerns nonetheless. While this research focused on monarch toxicity, other pollinators and beneficial insects are also at risk from pesticide contamination throughout the landscape.

“We can all play a role in restoring habitat for monarchs,” said Sarah Hoyle, Pesticide Program Specialist at the Xerces Society for Invertebrate Conservation and coauthor of the paper. “But it is imperative that farmers, land managers and gardeners protect habitat from pesticides if we hope to recover populations of this iconic animal.”

Field work, gathering plant samples, was completed last spring and summer. The lab work was completed by Nicolas Baert from the Department of Entomology and manager of the Chemical Ecology Core Facility at Cornell University. Statistical computations were completed this winter by Forister and colleague James Fordyce from the Department of Ecology and Evolutionary Biology at the University of Tennessee, Knoxville.

How butterflies protect themselves against rain


This 2016 video from Texas in the USA says about itself:

Butterflies Flying in Slow Motion HD – Houston Butterfly Museum

Several species of spectacular butterflies flying and courting in full HD slow motion at the Cockrell Butterfly Museum in Houston. For licensing contact hankschyma@yahoo.com

The Houston Museum of Natural Science and the spectacular Cockrell Butterfly Museum is home to dozens of incredible butterflies of all sizes and vibrant colors. This Slow motion HD video captures their beauty as they gallop through the air in 240 to 480 frames per second.

Music: Sonata Quasi Una Fantasia (aka Moonlight Sonata) Composed by Ludwig van Beethoven. Performed by Pecos Hank on the vibes piano.

Birds like rain after drought. Some butterflies also don’t mind.

From Cornell University in the USA:

Armor on butterfly wings protects against heavy rain

June 9, 2020

An analysis of high-speed raindrops hitting biological surfaces such as feathers, plant leaves and insect wings reveals how these highly water-repelling veneers reduce the water’s impact.

Micro-bumps and a nanoscale wax layer on fragile butterfly wings shatter and spread raindrops to minimize damage.

The study, “How a Raindrop Gets Shattered on Biological Surfaces,” published June 8 in the Proceedings of the National Academy of Sciences.

The research showed how microscale bumps, combined with a nanoscale layer of wax, shatter and spread these drops to protect fragile surfaces from physical damage and hypothermia risk.

There already exists a large market for products that use examples from nature — known as biomimicry — in their design: self-cleaning water-resistant sprays for clothes and shoes, and de-icing coatings on airplane wings. Findings from this study could lead to more such products in the future.

“This is the first study to understand how high-speed raindrops impact these natural hydrophobic surfaces,” said senior author Sunghwan “Sunny” Jung, associate professor of biological and environmental engineering in the College of Agriculture and Life Sciences. The lead author is Seungho Kim, a postdoctoral researcher in Jung’s lab.

Previous studies have looked at water hitting insects and plants at low impacts and have noted the liquid’s cleaning properties. But in nature, raindrops can fall at rates of up to 10 meters per second, so this research examined how raindrops falling at high speeds interact with super-hydrophobic natural surfaces.

Raindrops pose risks, Jung said, because their impact could damage fragile butterfly wings, for example.

“[Getting hit with] raindrops is the most dangerous event for this kind of small animal,” he said, noting the relative weight of a raindrop hitting a butterfly wing would be analogous to a bowling ball falling from the sky on a human.

In the study, the researchers collected samples of leaves, feathers and insects. The latter were acquired from the Cornell University Insect Collection, with the help of co-author Jason Dombroskie, collection manager and director of the Insect Diagnostic Lab.

The researchers placed the samples on a table and released water drops from heights of about two meters, while recording the impact at a few thousand frames per second with a high-speed camera.

In analyzing the film, they found that when a drop hits the surface, it ripples and spreads. A nanoscale wax layer repels the water, while larger microscale bumps on the surface creates holes in the spreading raindrop.

“Consider the micro-bumps as needles,” Jung said. If one dropped a balloon onto these needles, he said, “then this balloon would break into smaller pieces. So the same thing happens as the raindrop hits and spreads.”

This shattering action reduces the amount of time the drop is in contact with the surface, which limits momentum and lowers the impact force on a delicate wing or leaf. It also reduces heat transfer from a cold drop. This is important because the muscles of an insect wing, for example, need to be warm enough to fly.

“If they have a longer time in contact with the cold raindrop, they’re going to lose a lot of heat and they cannot fly very easily,” Jung said, making them vulnerable to predators, for example.

Repelling water as quickly as possible also is important because water is very heavy, making flight in insects and birds difficult and weighing down plant leaves.

“By having these two-tiered structures,” Jung said, “[these organisms] can have a super hydrophobic surface.”

The study was funded by the National Science Foundation and the U.S. Department of Agriculture.

Birds and butterflies of Voorne island


This 4 June 2020 video is about birds and butterflies of Voorne island in the Netherlands. In this order: black-tailed godwit, shelduck ducklings, avocet, little ringed plover, avocet with chicks, young redshank, white-tailed eagle, marsh harrier, redshank, oystercatcher, goldfinch, brown argus, common blue butterfly, white wagtail and common whitethroat.

How butterflies and moths got their eyespots


This 2019 video is called Watch This Caterpillar Turn Into A Chinese Luna Moth | The Dodo.

From the Florida Museum of Natural History in the USA:

Lyin’ eyes: Butterfly, moth eyespots may look the same, but likely evolved separately

May 6, 2020

The iconic eyespots that some moths and butterflies use to ward off predators likely evolved in distinct ways, providing insights into how these insects became so diverse.

A new study manipulated early eyespot development in moth pupae to test whether this wing pattern develops similarly in butterflies and moths. The results suggest that the underlying development of eyespots differs even among moth species in the same family, hinting that moths and butterflies evolved these patterns independently.

Influencing how eyespots form can lead to a better understanding of the respective roles genetics and the environment play in moth and butterfly wing patterns, said lead author Andrei Sourakov.

“Moths stumbled on a very successful evolutionary design over 200 million years ago,” said Sourakov, collections coordinator of the Florida Museum’s McGuire Center for Lepidoptera and Biodiversity. “That’s a long time for evolution to take place. It’s easy to assume that things that look the same are the same. But nature constantly finds a way of answering the same question with a different approach.”

Sourakov and co-author Leila Shirai, a biologist at the University of Campinas in Brazil, analyzed eyespot development in io and polyphemus moths, two species in the Saturniidae family. The eyespots in the two species responded differently to the study’s treatments, though the findings suggest the same signaling pathways were active. The researchers also found moths’ wing pattern development, which begins when they are caterpillars, slows just after they enter their pupal stage, a finding that echoes previous butterfly research.

Honing in on the signaling pathways involved in eyespot development — the molecular cascade that produces pigmentation and pattern in moths and butterflies — is central to determining the similarities and differences between moth and butterfly development, Sourakov said. Looking at DNA isn’t enough. Instead, scientists need to determine what happens after a gene is expressed to see if seemingly identical wing patterns truly are the same.

“Genetically controlled variation can look identical to environmentally induced variation,” Sourakov said. “Variation isn’t really produced by genes themselves, but by the intermediate product of the gene — in this case, molecular pathways.”

Sourakov and Shirai’s research expands on a 2017 study by Sourakov that showed molecules in the blood thinner heparin influenced eyespot development in moths.

In the new study, heparin triggered various changes in moth eyespots, including smudging and a shift in proportion. Despite similar molecular interactions, however, the changes were inconsistent between the io and polyphemus moths, potentially due to the different ways their wing patterns are mapped out by genes.

Sourakov and Shirai were able to detect wing development was likely paused just after pupation by delivering varying doses of heparin to caterpillars and pupae at different developmental stages. They also found eyespot tissue transplanted to a different region of the wing during pupation could induce patterning.

Natural history collections are key resources in revealing which wing patterns took hold genetically and became visible in populations, Sourakov said.

“Collections are where it all starts and where it all ends, frankly,” he said. “We can generally look at collections as a window into evolution, helping us understand which changes are just lab results and which ones can actually be observed in nature. Variation in genetics and physical characteristics is the toolbox for the evolution of diversity, and diversity is what we study at the museum. Collections help us understand that.”

Butterfly wing colours, new research


This video from the USA says about itself:

Blue Buckeye Butterflies – Junonia coenia

Buckeye Butterflies with a blue background on their wings are unusual. These were bred to bring out more of the blue color. They are raised at our farm, Shady Oak Butterfly Farm, in Florida. The first few generations only had a little bit of blue. Over a full year of breeding blue backgrounds with blue backgrounds, this generation has more blue butterflies emerge than any generation so far. July 2011.

From the Marine Biological Laboratory in the USA:

The evolution of color: How butterfly wings can shift in hue

April 7, 2020

A selective mating experiment by a curious butterfly breeder has led scientists to a deeper understanding of how butterfly wing color is created and evolves. The study, led by scientists at University of California, Berkeley, and the Marine Biological Laboratory, Woods Hole, is published today in eLife.

When the biologists happened upon the breeder’s buckeye butterflies — which normally are brown — sporting brilliant blue wings through selective mating, they jumped on the chance to explore what caused the change in color of the tiny, overlapping scales that produce the wing’s color mosaic and pattern. They found that buckeyes and other Junonia species can create a rainbow of structural colors simply by tuning the thickness of the wing scale’s bottom layer (the lamina), which creates iridescent colors in the same way a soap bubble does.

Structural color, often used in butterflies and other animals to create blue and green, is created by microscopic structures interacting with light to intensify some colors and diminish others. In contrast, pigmentary coloration is created by the absorption of specific colors (wavelengths) of light and is commonly employed to create colors such as yellow, orange, and brown.

“It was a surprise to find that the lamina, a thin sheet that looks very simple and plain, is the most important source of structural color in so many butterfly wing scales,” says first author Rachel Thayer. Previous studies of structural coloration had largely focused on some extreme examples and mostly involved analyzing complex, 3D shapes on the top of the scales.

First, the team showed that blueness in the selectively bred buckeye wings was, in fact, structural color and was generated largely by the lamina. They then compared these blue scales with wild-type brown scales, and found the same general architecture except the lamina was about 75 percent thicker in the blue scales. Finally, they measured lamina thickness in nine species of Junonia and a tenth species, Precis octavia, and found a consistent relationship with scale color.

“In each Junonia species, structural color came from the lamina. And they are producing a big range of lamina thicknesses that create a rainbow of different colors, everything from gold to magenta to blue to green,” says Thayer. “This helps us understand how structural color has evolved over millions of years.” The color shifts as lamina thickness increases according to Newton’s series, a characteristic color sequence for thin films, the team found.

“The color comes down to a relatively simple change in the scale: the thickness of the lamina,” says senior author Nipam Patel, director of the Marine Biological Laboratory. “We believe that this will be a genetically tractable system that can allow us to identify the genes and developmental mechanisms that can control structural coloration.” They identified one gene, optix, that can regulate lamina structural colors, and are currently searching for other candidates.

It was fortunate that the butterfly farmer, Edith Smith, had chosen buckeyes (Junonia coenia) for her mating experiment. For a variety of reasons, it is an ideal species for scientists to work with. “The buckeye genome is sequenced and other labs are working with it and have developed a number of experimental tools and protocols,” Patel says. “And it grows reasonably well in the lab, which is a big plus because many butterflies can be hard to raise.”

Smith’s bred buckeyes, which displayed “rapid evolution” from brown scales to blue, helped them to understand that the same, simple mechanism of tuning lamina thickness can facilitate evolutionary change that can span just several generations or millions of years.

See also here.

African monarch butterflies, new research


This 2012 video says about itself:

Danaus chrysippus, known as the Plain Tiger or African Monarch, is a common butterfly which is widespread in Asia and Africa. It belongs to the Danainae (“Milkweed butterflies”) subfamily of the brush-footed butterfly family, Nymphalidae. It is a medium-sized, non-edible butterfly, which is mimicked by multiple species.

The Plain Tiger is believed to be one of the first butterflies to be used in art. A 3500-year-old Egyptian fresco in Luxor features the oldest illustration of this species.

The Plain Tiger can be considered the archetypical danaine of India. Accordingly, this species has been studied in greater detail than other members of its subfamily occurring in India. The Plain Tiger is a medium-sized butterfly with a wingspan of about 7–8 cm. The body is black with many white spots. The wings are tawny the upper side being brighter and richer than the underside. The apical half of the fore wing is black with a white band. The hind wing has 3 black spots around the center. The hind wing has a thin border of black enclosing a series of semicircular white spots.

Background color and extent of white on the forewings varies somewhat across the wide range.

The male Plain Tiger is smaller than the female, but more brightly colored. In addition, male danaines have a number of secondary sexual characteristics. In the case of the Plain Tiger, these are:

The male has a pouch on the hindwing. This spot is white with a thick black border and bulges slightly. It is a cluster of specialised scent scales used to attract females.

The males possess two brush-like organs which can be pushed out of the tip of the abdomen.

Distribution

The range of the Plain Tiger extends from Africa and southern Europe, eastwards via Sri Lanka, India, and Myanmar to China and Sulawesi.

This picture shows butterflies on an ancient Egyptian fresco

This picture shows butterflies on an ancient Egyptian fresco.

From PLOS:

Male-killing bacteria linked to butterfly color changes

February 28, 2020

Like many poisonous animals, the African monarch butterfly’s orange, white and black pattern warns predators that it is toxic. Warning patterns like this are usually consistent across individuals to help predators learn to avoid them. However, a recent study, published February 27 in the open-access journal PLOS Biology, shows how a population of African monarch butterflies (Danaus chrysippus) breaks this rule and has highly variable warning patterns. The study, by Simon Martin of the University of Edinburgh, UK and colleagues shows that the unlikely answer lies in the interaction with a bacterium that specifically kills male butterflies.

Previous research had shown that all female butterflies in this East African population have two unusual features: Firstly, they have a new arrangement of their chromosomes where the chromosome containing genes that control color patterns is fused to their one of their sex chromosomes (called the W chromosome). This new chromosome is called the neo-W. Secondly, they are all infected with a bacterium called Spiroplasma that kills all of their sons. What was not clear, however, was whether these two features were linked, and whether they could explain the highly variable color patterns that changed from season to season.

To answer this, the researchers analyzed the entire DNA sequence of the bacteria and the female butterflies’ chromosomes. This showed that the neo-W chromosome alters color patterns and has spread rapidly through the population, aided by the male-killing bacteria. However, because the bacterium only allows female offspring, it promotes the survival of one particular color pattern gene that is always passed from mother to daughter. This left one puzzle for the scientists still to solve — if the females all carried the same color gene, then why was the East African population so variable?

The study found that this female color gene has only a weak effect that is overridden by color genes from the father. Therefore, fathers with different patterns will produce daughters with different patterns. Seasonal fluctuations in wind patterns are thought to affect which subspecies of male immigrants end up in this region, leading to seasonal changes in female color patterns. Even though they always resemble their father, the infected hybrid daughters, unable to produce sons, represent a genetic dead-end for fathers, whose color pattern genes only survive for one generation before being wiped out.

Dr. Simon Martin said, “The relatively fast emergence and spread of a new chromosome, combined with the short life cycle of the butterfly, allows us to study how the microbe is altering the evolution of the butterfly, almost in real-time. We are continually discovering new ways in which microbes manipulate their hosts, and male-killing is just one example of this. It makes you wonder to what extent the evolution of other organisms — even humans — is affected by such unseen forces.”