Key points
Gainesville, Fla --- Should you ever find yourself playing a trivia game on the topic of moths and butterflies, here are a few facts that might help. Collectively called Lepidoptera, moths and butterflies account for nearly 10% of all animal species.
In some environments, caterpillars consume more living leaves than all other animals in that environment put together. In about 10% of Lepidopterans, this process of bulking up during the larval stage is critical because the adults lack functioning mouthparts and die when their reserves run out.
Other species are prolific feeders. There are moths and butterflies that drink nectar, sap, urine, blood, sweat, tears, mucous, pus, moist feces and the emulsions of rotting fruit and animal flesh. Some species can even eat pollen, despite not having a jaw, by using their proboscis like an elephant trunk to scoop up samples from multiple flowers, coat them in external digestive juices and slurp up the resulting polyglot slop of liquified pollen grains.
Actually, about 2% of Lepidopterans — in a group called non-ditrysians — do have jaws. They’re weird and have several additional physical features and behaviors that distinguish them from other Lepidoptera.
This is just a smattering of what humans have learned about moths and butterflies during our long, shared history, and we’re learning more all the time. In fact, discoveries are now being made so frequently that it’s even hard for scientists to keep up.
Researchers at the Florida Museum of Natural History, the Wellcome Sanger Institute, the University of Montpellier, the University of York, Harvard University and Lund University recently condensed what we do and don’t yet know about moths and butterflies in a convenient review article , published in the journal Nature Reviews Biodiversity .
“Even though moths and butterflies are a well-studied group, we’re just now beginning to understand some of the most basic facts about their evolution and conservation needs,” said senior author Akito Kawahara , a curator at the Florida Museum’s McGuire Center for Lepidoptera and Biodiversity. “There’s still so much more to do.”
Moths originated 300 million years ago and diversified with a little help from a fungus and bacterium
To really understand moths and butterflies, you first need to know a few things about their closest relatives, the caddisflies. These small, four-winged creatures are the artisans of the insect world, adept at stonemasonry, carpentry, sand-shaping and shell-crafting. They use these skills to construct intricate cases for their aquatic larvae to protect them from fish.
Because they’re aquatic, caddisfly larvae primarily subsist on algal cells, diatoms and small invertebrates they catch with silk awnings they string up just outside their cases. In contrast, almost all moth and butterfly larvae live on land and eat young, supple leaves and wood.
Land plants are famously averse to having their vegetative bits munched on and have consequently evolved the world’s largest natural pharmacopeia of organic toxins to deter herbivores. Insects, who never seem to have taken the hint, have responded by evolving immunity to said toxins on countless occasions.
The ability to consume land plants seems to have been a key factor that led to the origin of moths 300 million years ago. But they didn’t entirely evolve this new ability on their own. According to research conducted by scientists at the Florida Museum, the American Museum of Natural History, the University of Florida and Brigham Young University, moths instead at least partially obtained it from fungi through a process called horizontal gene transfer. The new fungal gene likely helped them digest tough plant tissues and detoxify some of the compounds meant to deter them.
The oldest Lepidoptera fossil ever found was preserved in the Jurassic, about 190 million years ago. This means that there are no known fossils from the first 100 million years of moth evolution. Scientists don’t know how many species there were during this time or where they lived. But they do have a relatively good idea of what they may have looked like, thanks to a few ancient leftover lineages that managed to hang on — barely, in some cases — to the present time. These are the moths with jaws, or — more technically— mandibles.
Despite there being only about 250 living species of mandibled moths, they come in a greater variety of shapes than the 180,000 or so moths and butterflies without mandibles, though a microscope is required to see most of these differences, given their small size. This strongly suggests that mandibled moths were once incredibly diverse but have since gone mostly extinct. This is reflected in their relationships and distributions as well.
The family Agathiphagidae, for example, has just two species, one of which can only be found in the Northeast corner of Australia. The other has a slightly larger distribution on a few islands in the southern Pacific. The existence of these moths was scientifically unknown until 1947, when “In February…I received some seeds of Agathis vitiensis , a species of Kauri pine…with a request that I endeavor to rear out and identify the insect with which they were infested,” wrote the New Zealand entomologist Lionel Dumbleton. The small adult moths are furtive and hard to find, which may be partially due to the fact that they’re only active during the part of year when their host trees are producing cones, on which they lay their eggs. The legless larvae bore into the seeds and can remain in diapause — suspended between the plump life of a caterpillar and the sleek physique of an adult moth — for up to 12 years.
Then there are the equally small and ancient micropterids, made up of about 150 species and retaining features that were likely possessed by their ancestors. This includes their diet, which — in adults — consists of spores and pollen. The caterpillars of several species eat liverworts, a group of seedless plants with cells resembling alligator skin that just so happen to be one of the first groups of plants to evolve on land 470 million years ago, meaning there were plenty of them to go around when caddisflies came out of the water.
The only other Lepidoptera with jaws are a group of mysterious metallic moths that can occasionally be spotted near beech trees in remote parts of Patagonia.
Though all three of these groups are now rare, they were once the epitome of what it meant to be a moth. They might have stayed that way, too, had it not been for another horizontal gene transfer, this time between a moth and a bacterium that took place sometime during the Triassic, back when dinosaurs first became major players on the world stage and the supercontinent Pangaea began its long and messy separation. Scientists discovered this event in the same 2025 study in which the horizontal gene transfer between moths and fungi was reported.
“The discovery was surprising initially, but we have now come to realize that such horizontal gene transfer events are more common than we originally thought,” Kawahara said. “It’s really incredible to think that a few gene transfer events could have led to such a major impact in the evolution of Lepidoptera and their diversity.”
Thanks to bacteria, Lepidoptera leveled up by gaining the ability to digest plant sugars, like the ones dissolved in floral nectar. Coincidentally, moths also evolved a proboscis at around this time. They were now well on their way to becoming the pollinating powerhouse that they are today. There was just one problem, which was that flowers didn’t exist yet.
Today, insect pollination is generally associated with flowering plants, and for good reason. There are more than 300,000 flowering plant species, and roughly 90% of them rely, to some extent, on insects to transfer pollen from one flower to another. But plants were using insects as their personal genetic couriers long before flowers arrived on the scene.
The first seed plants, called gymnosperms , began diversifying during the Devonian period, about 380 million years ago. Instead of flowers, gymnosperms have cones. The earliest ancestors of gymnosperms specifically had male cones that produced pollen and female cones that produced eggs. Pollen grains were blown from their cones by wind and wafted into a diffuse haze that will be familiar to anyone who’s ever suffered from spring allergies. Female cones exuded a small, liquid droplet on their surface that sieved the botanical aerosol as it breezed by, entraining a few pollen grains in the process. In modern species, the pollen releases a chemical signal that tells the plant to stop pumping water into the droplet, after which the liquid quickly evaporates, and the pollen is pulled inside the cone, where fertilization takes place.
It didn’t take long for insects with needle-like stylets — which they used to pierce through plant tissue and suck out sugar — to begin helping themselves to this rich source of proto-nectar at the plant’s expense. But such interactions remained relatively uncommon until, beginning about 228 million years ago, the planet underwent a prolonged period of warm and dry conditions that suddenly made a diet that mostly consisted of water an indispensable way for insects to keep cool.
The first insects with proboscises evolved during this time, including a group called Glossata, which today contains 98% of all moth and butterfly diversity. Plants had, by then, figured out a way to benefit from the free-loading insects by evolving cones that had both male and female reproductive organs. Whenever an insect crawled over one of these for a sip, it invariably came away with a few sticky pollen grains adhering to it, which it carried to the droplet of another cone. Plants likely started pumping more sugar into the droplets to actively attract insects. This new, mutualistic arrangement resulted in the diversification of early moths and the plants they pollinated.
Butterflies followed bees, bats went after moths
The first flowers didn’t show up until much later, 150 or so million years ago, but even then, they may not have been of much interest to moths. Many of the earliest flowers emitted scents that attracted beetles, which seem to have been their primary pollinators. It wasn’t until a group of carnivorous wasps started using flowers 120 million years ago that things really took off. These were the ancestors of modern bees, and they relied, to a great extent, on their vision to find their way around and acquire food.
That meant flowers had to be colorful to attract them and open during the day, when there was more light to see by. Moths were mostly nocturnal and had eyes with limited color vision that were adapted to see in the dark. The pollination droplets moths used for food achromatically glinted like crystals in moonlight, revealing their location.
But one group of moths switched from night- to day-flying to take advantage of the colorful nectar depots and thereafter evolved into butterflies . Other moths have made similar transitions to day flying, but none have become as diverse as butterflies.
Moths that remained nocturnal did eventually benefit from this new source of nectar as well. Many flowering plants evolved white, night-blooming flowers that, thanks to the albedo effect, are just as effective, if not more so, at attracting moths as pollination droplets, resulting in the further diversification of both groups.
Then, about 55 million years ago, a group of mammals learned how to fly. Bats had made their debut. Ten million years earlier, an asteroid impact killed off all the non-avian dinosaurs, but birds stuck around and, with their keen eyesight, they soon cornered the daytime aerial hunting market . In contrast, the night skies were comparatively empty, aside from all the moths and other tasty insects that were flying around. So bats sold their stock in eyesight and invested in echolocation. This sparked an evolutionary arms race between moths and bats that’s still ongoing today.
Several moth lineages appear to have independently evolved hearing organs just before the origin of bats, though scientists are unsure what they were listening to. The hearing organs of most modern moths, however, are attuned to high frequencies above the level at which humans can hear, meaning whatever these organs had initially been used for, they were ultimately calibrated to detect the ultrasound produced by bats.
Some of these species, and others without the ability to hear, evolved sound-producing organs, often out of whatever spare parts they happened to have lying around, including their genitals .
"Many have them on the thorax or abdomen, but some have hearing organs on their mouthparts or wings,” Kawahara said. “I think we will find many more hearing organs on different moth species and also discover countless new moth morphological and behavioral defense strategies against bat predators."
Genomes illuminate how biodiversity evolved and guide conservation efforts
Most of these discoveries were made by sequencing and studying genomes, which contain the full complement of an organism’s nuclear DNA. It took experts more than 10 years to fully sequence and assemble the human genome, which was completed in 2003. But sequencing technology has rapidly advanced in the intervening decades, to the extent that scientists are now boldly attempting to sequence the genomes of all eukaryotic species, currently estimated at about 1.8 million.
This effort falls under the umbrella of the Earth BioGenome Project , a network of sequencing initiatives spread out across multiple countries. This includes Project Psyche , which has the comparatively modest goal of merely sequencing genomes for all 11,000 of Europe’s moth and butterfly species.
The study’s co-lead author, Charlotte Wright, is a postdoctoral fellow at the Wellcome Sanger Institute and research fellow at Darwin College, University of Cambridge. Wright is one of the leaders of Project Psyche and studies the evolution of genome structure, a field of research that’s poised for a Renaissance-sized scale of revitalization with all the forthcoming genomes that will soon be available.
“The next 10 to 20 years will be really exciting and allow us to explore a new layer of genetic change that was previously out of reach,” Wright said.
Most Lepidoptera species have a respectable number of chromosomes, with an average hovering at around 31, close to the 23 chromosomes possessed by humans.
“But some groups have thrown this normal rule book of stability out the window,” she said.
One such example is the Atlas blue butterfly ( Polyommatus atlantica ), which has ripped its chromosomes into pieces to the extent that it now has the highest known chromosome number of any animal (excluding protists).
“I knew I had to sequence the Atlas blue during my PhD because it had previously been found to have over 200 chromosomes. Sequencing the genome allowed us to understand how this spectacular number of chromosomes evolved.”
Another species, the cabbage white butterfly ( Pieris rapae ), appears to have similarly fragmented its chromosomes in the past, but later seems to have stuck them back together , leading to a more manageable 25 chromosomes.
Genomes are also a critical conservation tool that can be used to assess how susceptible a species is to extinction, as was retroactively the case for the Xerces blue ( Glaucopsyche xerces ), considered to be the first butterfly extinction caused by human activity. The species disappeared in the early 1940s after its habitat was disturbed and destroyed by development.
Using decades-old museum specimens, scientists sequenced the Xerces blue genome. Subsequent analyses revealed the species had originated 850,000 years ago but had suffered population declines for tens of thousands of years, with signs of inbreeding, that may have rendered it vulnerable to extinction when its environment was suddenly and thoroughly altered.
If scientists know ahead of time which species are most genetically vulnerable to human activity, they may be able to prevent similar extinctions from occurring in the future.
Recording and countering modern losses
The authors report in the study that moths and butterflies have been steadily increasing in diversity since the origin of the group 300 million years ago. Recently, however, the abundance of moths and butterflies has taken a nosedive, which is concerning for multiple reasons, said study co-lead author Vaughn Shirey , a curator of Lepidoptera at the McGuire Center.
Having largely co-evolved with flowering plants, they’re a critical component of pollination. They’re also somewhere down near the foundation of nature’s food pyramid.
“One of their primary ecological roles is being eaten by other things. Micromoths are probably really important for bats, as much as caterpillars are for birds and other insects,” Shirey said, referring a group of unrelated moths that have independently shrunk down to and below the size of a U.S. penny. Their small size makes them hard to find and study, and scientists consequently know little about them.
Compared to micromoths and most other insects, scientists know a lot about the large, charismatic butterflies, which makes the strong signal of their declining abundance concerning for even more ominous reasons.
“They’re exceptional bio-indicators for ecosystem integrity,” Shirey said. “They’re quite sensitive to ambient environmental temperatures and changes in precipitation, and they’re very closely tied to their host plants. They’re sort of like little barometers of environmental conditions.”
A sudden drop in the butterfly barometer is likely indicative of a storm. If there’s a silver lining, it’s that researchers and volunteers have created a network of “weather” stations, in which Lepidoptera diversity and abundance is regularly monitored. Shirey’s graduate advisor at Georgetown University, Leslie Ries, founded one such station in 2012, called the North American Butterfly Monitoring Network, with funding from the National Science Foundation. The program is staffed almost entirely by volunteers nationwide and makes its data freely available.
“These data are currently the only information we have on abundance for butterflies in the country, other than trying to piecemeal studies together that have done similar work in terms of large-scale coordination,” Shirey said.
Monitoring efforts exist in other parts of the world, but many of these typically only measure the presence or absence of a species, not the number of individuals in a population. The latter requires significantly more work and funding than the former. This makes it impossible to determine whether a species is thriving in an area or on its way out.
“Much of sub-Saharan Africa, South America and even places like Australia and New Zealand — we’ve done a pretty good job of documenting some of these areas, but they just haven’t been assessed. And there are areas where we really don’t even know what’s there, so we can’t even layer the assessment on top of that.”
Scientists have extensively studied the causes of insect declines , which include the widespread use of pesticides, habitat destruction, invasive species and climate change. Light pollution is also a major problem for nocturnal insects. Yash Sondhi, a former postdoctoral fellow at the museum, recently helped determine why electric lights are so disruptive and deadly to insects. Rather than being attracted to illuminated light bulbs, per se, they mistake them for the moon and stars, which they use to orient themselves. Because starlight and moonglow always come from above, they keep their backs to it when flying. They try to do the same thing with artificial light and inevitably end up caught in a spiraling death trap.
But scientists also have a lot to say about how individuals can help conserve insects, from turning off outdoor lights or using bulbs that emit soft yellow light to growing pollinator gardens and foregoing pesticides.
“One thing that people often don’t think about is leaving some leaf litter on the ground,” Shirey said. “Many insects, especially moths, overwinter in that litter, and so when you bag it up, they die.”
If you’re looking for more tips on how to support native insects, the museum has put together a short list of recommendations .
Other authors of the study include Fabien Condamine of the Université de Montpellier; Jane Hill of the University of York; Naomi Pierce of Harvard University; and Niklas Wahlberg of Lund University.
Nature Reviews Biodiversity
Evolution, genomics and conservation of butterflies and moths
16-Feb-2026