This Insect Has Been Around for More Than 100 Million Years. Here’s the Secret to Its Longevity.

Countless species of insects have been around for hundreds of millions of years, including pests like cockroaches and beetles. More specifically, the rove beetle (Staphylinidae) — which has over 66,000 species — dates as far back as dinosaurs. This beetle has learned to thrive by adapting to its environment and exploiting its prey. In fact, it’s even developed similar characteristics to other orders (like ants and mites) for its own survival.

But how, exactly, have these creatures developed and maintained these protective characteristics? A new study published in Cell found the answer to this question. Here’s the secret sauce fueling the rove beetle’s longevity.

What Fuels the Rove Beetles’ Longevity?

Scientists have officially discovered and analyzed the two cell types in the rove beetle’s tergal gland that produce protective repellants. Essentially, one cell creates a toxic chemical (like benzoquinone), while the other creates an activating liquid. Together, the two cells repel predators and protect the beetle from harm. This process is similar to how plants produce poisons as a protective mechanism. 

“The rove beetle tergal gland is this incredible, reprogrammable device for making new chemistries and evolving new interactions,” said Caltech biologist Joe Parker, a corresponding author of the study, in this article by Caltech. “It enabled these beetles to achieve extreme forms of ecological specialization. Without the gland, there would have been no getting into the weird and wonderful niches that these beetles have found themselves.”

For over 100 million years, the rove beetles’ gland chemistry has continued to adapt. In addition to repelling predators, these glands allow them to dominate new environments. For example, some of the species can mimic prey like mites and ants by producing similar chemicals. In many cases, rove beetles can infiltrate entire ant colonies via myrmecophily. Basically, these beetles are massive manipulators, convincing ants they are one of their own — all thanks to their tergal glands.

What’s more? Once the beetles live alongside aggressive ant colonies, during evolution, many of them lose their glands and simply adapt to their co-inhabitants. 

“Apparently, once you have lived inside an army ant colony of millions of aggressive ants for long enough, you no longer need the gland,” explained postdoctoral scholar Sheila Kitchen, lead study author and an assistant professor at Texas A&M University, in the same Caltech article.

The rove beetle’s tergal gland is located at the tip of its abdomen. It’s also a prime example of macroevolution. The gland’s successful evolution is the driving force behind the insect’s diversification into over 66,000 species.

How Scientists Studied Rove Beetles’ Longevity

To draw such remarkable conclusions, the scientists analyzed genomes across various beetle species. Through this research, they discovered that the rove beetle has maintained its tergal gland for over 100 million years. In fact, they traced the gland back to its development during the Early Cretaceous period. 

The scientists also studied the evolution of two specific cell types in the tergal gland and their complex chemical defense system. They achieved this by “regramming” the cell types or tweaking the genes/gene functions. This helped them better understand the rove beetle’s chemical abilities and ecological specialization. 

This research has allowed the study authors to identify similarities in the gland’s genetic architecture across various rove beetle species. Some of these ancient genes have repurposed themselves by adopting new functions to help the beetle survive and adapt to its environment. Additionally, some rove beetle species have even developed evolutionarily new genes to achieve these new protective functions. Coupled with their repurposed and entirely new genes/functions, it’s no wonder the rove beetle is so resilient.

How Are Rove Beetles Similar to Plants?

As mentioned earlier, similar to some plants, rove beetles can produce toxic chemicals that repel predators. According to the study published in Cell, scientists identified “molecular evolutionary steps leading to benzoquinone production by one cell type via a mechanism convergent with plant toxin release systems, and synthesis by the second cell type of a solvent that weaponizes the total secretion.” Together, the two cells have kept the rove beetle family alive and thriving for over 100 million years.

Much like plants, the rove beetle has developed these protective cellular functions—back by toxic chemicals—without harming or poisoning themselves. This allows them to defend themselves against predators without enduring negative consequences from their own toxins.

These plant-like abilities have helped the rove beetle to explode into over 66,000 species. Their powerful self-protective chemicals allow them to escape predators and manipulative prey. Not only is this a testament to their previous evolution but also to their continued evolvability.