Dung Beetles Adapt to Climate Change by Burying Eggs Deeper

As global temperatures rise, some species are adapting in surprising ways. A recent study highlights a fascinating behavioral shift in rainbow scarab beetles, offering a potential glimpse into how at least some insects might cope with the challenges of a warming world. Researchers have found that these beetles are digging deeper underground to protect their eggs from increasingly warmer temperatures.

Rainbow scarabs (Phanaeus vindex) are a type of tunneling dung beetle. Unlike some of their cousins that roll dung into balls across the ground, these beetles excavate tunnels and bury dung within them, forming a hardened sphere around a single egg. This underground chamber serves as a crucial incubator for their developing young.

The research, presented at a meeting of the Society for Integrative and Comparative Biology in Portland, Oregon, on January 6, 2026, involved a series of experiments where researchers simulated global warming using plastic “greenhouses” placed over buried buckets of soil. These cones increased the temperature inside by approximately 2 degrees Celsius compared to the surrounding environment. The study, led by ecologist Kimberly Sheldon of the University of Tennessee, Knoxville, revealed a significant response from the beetles.

“We found that female rainbow scarabs buried their eggs an average of five centimeters deeper – about 21 centimeters from the surface – when exposed to the warmer conditions,” Sheldon reported. This deeper burial lowered the incubating temperature by roughly 1 degree Celsius. The initial work began over six years ago, and while a previous study site was lost to flooding, subsequent research in 2023 confirmed the initial findings: just as many young beetles emerged as adults from the deeper dung balls as from those buried at shallower depths.

This behavioral adaptation suggests a degree of resilience in rainbow scarabs. By digging deeper, the beetles are effectively creating a more stable and cooler microclimate for their offspring, mitigating the impact of rising surface temperatures. This is particularly noteworthy as other species, including some closely related beetles, do not exhibit the same flexibility.

Researchers also investigated a tropical cousin of the rainbow scarab, Oyxternon silenus, in Ecuador. Surprisingly, these beetles did not alter their burrowing depth in response to the simulated warming. The implications of this difference are still being explored, but it suggests that the ability to adjust burrowing behavior may be linked to the environmental variability experienced by a species. Tropical climates, generally less variable than temperate ones, may not have exerted the same evolutionary pressure for behavioral adaptation.

The lack of a similar response in the tropical species is “concerning,” according to Sheldon, raising questions about their vulnerability to climate change. The ability to modify behavior in response to environmental stressors is a key factor in a species’ ability to survive and adapt. If a species lacks this flexibility, it may be less equipped to cope with the rapid changes brought about by global warming.

This research builds on a growing body of evidence suggesting that some animals are already responding to climate change by altering their behavior. Studies have shown similar adaptations in sweat bees and tree frogs. However, the findings also underscore the fact that not all species possess the same capacity for behavioral plasticity.

The study highlights the importance of understanding how different species respond to climate change, and the potential consequences of those responses. While the rainbow scarab’s adaptation offers a glimmer of hope, the contrasting response of its tropical cousin serves as a reminder that the impacts of climate change will be felt unevenly across the natural world. Further research is needed to fully understand the long-term implications of these behavioral shifts and to identify species that may be particularly vulnerable to a warming planet.

The findings also contribute to a broader understanding of how insects, a critical component of many ecosystems, might fare in the face of climate change. Dung beetles, for example, play a vital role in nutrient cycling and soil health. Changes in their behavior or population dynamics could have cascading effects on the ecosystems they inhabit.