Researchers in China have detailed their discovery of the earliest known wormlion in 99‑million‑year‑old amber, closing a large gap in the fossil record and revealing how these rare fly pollinators evolved alongside ancient plants. Shown here is one of the fossilized specimens of the species the researchers have named Crevermileo cnuae. (Image originally published in Feng et al 2025, Insect Systematics and Diversity)

By Melissa Mayer

Melissa Mayer

Everyone loves a pollinator. As bees and butterflies zip between blooms, spreading pollen, we witness the relationship between pollinators and flowering plants—and it keeps us fed.

Unlike their flashy contemporaries, fly pollinators are underappreciated. Yet they’re the second most important insect group in that role (after bees). Teasing out how flies evolved to fill this niche can be tricky, especially for rarer families.

That’s why researchers from China’s Capital Normal University, Guizhou University, and Guangdong Academy of Sciences looked at phylogenetics and the fossil record to figure out when wormlions (Vermileonidae) diversified. Their study, published in October in Insect Systematics and Diversity, describes the earliest known wormlion fossil, deposited in Burmese amber during the Cretaceous period about 99 million years ago.

“Our team has been dedicated to palaeoentomology research for over 30 years, with the goal of uncovering missing links in insect evolution and revealing diverse ancient insect lineages,” say Yongjie Wang, Ph.D., and Dong Ren, Ph.D., two of the coauthors. “We believe our work plays a crucial role in understanding what drove the evolutionary pathways and shaped the diversification of modern insects.”

Peering Back Through Time

Approximately 66 million years ago, an asteroid famously hurtled through Earth’s atmosphere, crashing to the surface and triggering the extinction of three-quarters of all plants and animals, including the non-avian dinosaurs.

After a recovery period, flowering plants took off, eventually rising to the dominance they now enjoy. And flowers need pollinators.

Wormlions are rare fly pollinators, comprising 65 living species and—until now—a single fossil species from Baltic amber, dated to just 38 million years ago.

Researchers in China have detailed their discovery of the earliest known wormlion in 99‑million‑year‑old amber, closing a large gap in the fossil record and revealing how these rare fly pollinators evolved alongside ancient plants. The fossils were encased in mid-Cretaceous Kachin ambers deposited in the Department of College of Life Sciences, Capital Normal University, Beijing, China. (Photo courtesy of Dong Ren, Ph.D.)

Adult wormlions feed on nectar they sip from flowers. Wormlion larvae hunt by digging pits, flailing about to fling loose soil from the sandy traps. When unsuspecting prey wanders in, the sand-obscured wormlion grabs it, injecting venom before devouring.

Molecular data tells us that wormlions likely emerged during the Jurassic period, smack dab in the middle of the era when dinosaurs roamed. But there simply weren’t wormlion fossils to back this up before—and wormlions didn’t even have a genus-level family tree.

“There was a gap of over 120 million years in the fossil record, leaving the group’s early evolution—and especially its interactions with plants—poorly understood,” say Wang and Ren.

Constructing the Wormlion History

So, the team got to work building that phylogenetic framework, including all 66 known genera, both living and extinct. That includes the new species from the amber fossil (Crevermileo cnuae) described in the paper—and now the earliest known wormlion.

Those ancestral wormlions had short mouthparts with a flat facial area (clypeus) just below the antennae. That’s distinct from the mouthparts of later wormlions, which are longer with a convex area. The pattern is like what we see in fossils from related fly pollinators.

“The new species can be clearly identified as a vermileonid, yet it shows primitive characteristics that offer unique clues about the early evolution of the family—something previously based only on speculation,” say Wang and Ren.

It seems that wormlions enjoyed two waves of diversification: one back when non-flowering plants (gymnosperms) dominated and another about 100 million years ago when flowering plants (angiosperms) were diversifying and spreading. The wormlion’s mouthparts likely adapted to reach nectar in the long floral tubes of their host flowers.

Researchers in China have detailed their discovery of the earliest known wormlion in 99‑million‑year‑old amber, closing a large gap in the fossil record and revealing how these rare fly pollinators evolved alongside ancient plants. Here, the family Vermileonidae is detailed in a time-calibrated phylogenetic tree. The vertical axis shows the numbers of lineages of angiosperms and gymnosperms, indicated via yellow and blue lines. (Image originally published in Feng et al 2025, Insect Systematics and Diversity)

Pollinator Diversity

These findings highlight the dynamic nature of pollinator evolution. Some pollinators—like bees and butterflies—are super widespread and diverse, with relatively basic ancestors. But others—like wormlions—specialized early and are now comparatively limited as a group.

That tells us a lot about what the world once looked like and how it got that way.

“By studying less familiar groups like vermileonid flies, we gain a deeper understanding of how modern pollinators diversified and how present-day terrestrial ecosystems came to be structured,” say Wang and Ren. “Fossils are therefore indispensable in reconstructing the evolutionary history of insects.”

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