With a wingspan about the size of a penny, Nannophya pygmaea is the smallest dragonfly known to science. Its two distinct populations in east Asia rarely mix, and a new study examining N. pygmaea combines genetics and climate models to explore isolation, habitat shifts, and the gray area between populations and species. (Photo by budak via iNaturalist, CC BY-NC 4.0)

By Melissa Mayer

Melissa Mayer

Dragonflies are known for their size. Some motor through life in robust bodies with such fierce flying power that an iconic entomology textbook recommends “a gun loaded with dust shot” as a practical tool for collecting them.

But the Odonata order is diverse, and no species proves that quite like Nannophya pygmaea, sometimes known as the scarlet pygmy dragonfly. With a wingspan of just 20 millimeters—about the diameter of a penny—these are the smallest dragonflies known to science. And they’re weak flyers, inhabiting wet habitats along the Pacific coast of eastern Asia and nearby islands as distinct populations that aren’t likely to encounter each other.

When a team at the American Museum of Natural History (AMNH) began picking projects for their summer interns, that small dragonfly stuck out. The result of the project, published in February in the Annals of the Entomological Society of America, looks at the population structure of the species as well as past and future distributions.

Distribution—Yesterday, Today, and Tomorrow

The team tracked public data points for Nannophya pygmaea observations along with climate variables—like silt content and rainfall seasonality—to model where the small dragonfly is most likely to be found today. Then they mapped that onto existing models for the same variables during the last ice age and projected forward to 2070.

“That sort of took it from this mystery of how on earth this tiny dragonfly got to all these different islands and all across Asia, and suddenly … there were possibilities—there’s this open corridor of land and suitable habitat,” says Daniel Davis, former summer intern at AMNH and lead author on the study.

With a wingspan about the size of a penny, Nannophya pygmaea is the smallest dragonfly known to science. Its two distinct populations in east Asia rarely mix, and a new study examining N. pygmaea combines genetics and climate models to explore isolation, habitat shifts, and the gray area between populations and species. Here, the geographic location of populations analyzed in the study are shown; they fall into two distinct groups: a northern assemblage in Japan, South Korea, China, and Laos and a southern assemblage in Malaysia and Indonesia. (Image originally published in Davis et al. 2026, Annals of the Entomological Society of America)

Today, there are at least two distinct scarlet pygmy populations: the northern assemblage, which inhabits an area that includes Japan, South Korea, China, and Laos, and the southern assemblage of Malaysia and Indonesia. Since they’re weak flyers, the groups don’t really mix.

That’s led some to question whether these dragonflies comprise multiple species—including a proposed new classification of a segment of the northern population as Nannophya koreana.

The team looked at genetic data for each population and within the populations. They didn’t confirm N. koreana as a distinct species—yet.

“At the end of the day, it really is subjective,” says Lacie Newton, Ph.D., former postdoctoral researcher for the project. “I usually tend towards taxonomic stability. So, if there aren’t more clearcut boundaries within those species, I lean towards saying this is population subdivision, maybe even incipient speciation—in which case, it’s really early on in that speciation process.”

With more data and direct examination of N. pygmaea specimens, that may change. Here, it came down to how isolated the populations are and whether it looks like they occupy different ecological niches. The team didn’t see that niche specialization here.

“People like to think of it as instantaneous—like, snap your fingers and you have two different species. But it’s really not that simple,” says Jessica Ware, Ph.D., division chair of invertebrate zoology at AMNH, who supervised the project with Newton.

Protecting the Scarlet Pygmy Dragonfly

While an intern at the American Museum of Natural History, Daniel Davis led a project that studied population structure and past and future distributions of Nannophya pygmaea, sometimes known as the scarlet pygmy dragonfly. (Photo by Jessica Ware, Ph.D.)

Right now, South Korea has declared the N. pygmaea an endangered species, but it’s classified as a species of least concern by the IUCN Red List.

When the team projected to 2070, they found a more fragmented and regionally reduced habitat with some islands becoming essentially uninhabitable for the dragonflies. It’s likely some populations will shift as the climate changes; others won’t be able to adapt because they simply can’t fly far enough to find a suitable habitat.

It all comes down to taxonomic sampling. More data would help scientists understand this group of dragonflies and their relative risk. South Korea has gobs of data, compared with other locations, but the team says looking at isolated populations or making isolated policy decisions—like a single nation or, in the case of the United States, state by state—is a weakness when it comes to insect decline.

“It strikes me as remarkable that Nannophya is gorgeous. It’s hot pink with red—and just as pretty as a butterfly,” says Ware. “If we are in 2026 and only scratching the surface of what the population is like and its conservation status, it makes me wonder what the fate is for all the other insects that aren’t charismatic. What does that bode for maggots and earwigs?”

Like dragonflies, the temporary team has dispersed. But they say this work isn’t over. They’ll continue to collaborate on behalf of Nannophya pygmaea and its relatives.

And that’s no small thing.

Melissa Mayer is a science writer and the human behind Washington State University’s science cat, Dr. Universe. Email: [email protected].