Insect Discovered

Paleontologists have uncovered an ancient parasitic wasp species, Sirenobethylus charybdis, that thrived 99 million years ago during the Cretaceous period. Encased in amber, the wasp exhibited an exceptional evolutionary adaptation: a Venus flytrap-like structure on its abdomen. Researchers believe this mechanism allowed the wasp to trap other creatures, potentially turning them into unwitting hosts for its larvae. The findings, published in the journal BMC Biology, provide new perspectives on the diversity of life during prehistoric times.

The fossilized remains of Sirenobethylus charybdis were studied in 16 specimens preserved in amber sourced from Myanmar. Amber is renowned for capturing ancient organisms with remarkable three-dimensional clarity, offering researchers a rare opportunity to observe extinct species. The wasp's movable abdominal structure appeared in different positions across specimens, leading scientists to hypothesize its function as a grasping mechanism.

"When I looked at the first specimen, I noticed this expansion at the tip of the abdomen, and I thought this must be an air bubble," Lars Vilhelmsen, a coauthor of the study and a curator at the Natural History Museum of Denmark said. "But then I looked at a few more specimens and went back to the first one. This was actually part of the animal."

The researchers propose that Sirenobethylus charybdis may have used this structure to immobilize other flying insects of similar size. Once grasped, the host would be injected with eggs, which eventually developed into parasitic larvae. Such behaviors align with parasitoid wasps observed today, whose larvae survive by feeding on their hosts. However, the adaptation of Sirenobethylus charybdis is unique, raising questions about its specific evolutionary purpose.

“One thing I've always thought about stuff like that is that it's the closest thing to a picture of the past,” Newtown resident Collin Granville said.

Phil Barden, an associate professor at the New Jersey Institute of Technology who was not involved in the study, highlighted the significance of the discovery while urging caution regarding the interpretation of the abdominal trap. "Today, thousands of parasitoid wasp species are capable of immobilizing hosts without abdominal clasping. Why was this adaptation necessary for these ancient wasps?" Barden said.

Barden also suggested alternative functions for the structure, such as detecting prey in soil or transporting young. The researchers emphasize that while their main hypothesis is supported by the proximity of the egg-laying organ to the trap-like adaptation, the absence of male specimens leaves room for additional theories. The structure may have played a role in mating or other ecological behaviors.

“I think it's really cool how they've been able to figure this out even though it was preserved for a long time, and they didn't have the ability to physically evaluate the species while it was alive,” NHS sophomore Sierra Marx said.

Amber fossils offer paleontologists a glimpse into prehistoric ecosystems. Other notable finds have included dinosaur tails, ancient spiders, and even flowers encased in the resin. The amber housing Sirenobethylus charybdis originated from Myanmar’s Kachin region near the Chinese border. Initially purchased by a fossil enthusiast, it was later donated to the Key Laboratory of Insect Evolution and Environmental Changes at Capital Normal University in Beijing.

The use of amber from Myanmar, however, has generated ethical concerns among scientists. The region has faced political instability, particularly following a military coup in 2021. Some researchers have called for a moratorium on studies involving amber sourced from Myanmar to address potential ethical issues surrounding its procurement.

“I think it's really cool that the amber is able to preserve something in such a great manner, leading to more discoveries all over the world, all of the time,” NHS senior Emma McIntosh said.

Despite such challenges, discoveries like Sirenobethylus charybdis continue to broaden our understanding of ancient life. "This is something unique, something I never expected to see, and something I couldn’t even imagine would be found," Vilhelmsen said. "It’s a 10 out of 10."

The “unusual” wasp adds to the growing list of extinct insects with adaptations that challenge current boundaries of known insect evolution. Amber fossils remain a treasure trove for paleontological studies, revealing evolutionary behaviors and the hidden intricacies of life on Earth millions of years ago.