Not exactly the poster child for cute animals, dung beetles now join the list of species affected by human-caused climate change.
Indeed, the long tentacles of climate change now extend all the way into the dreary lives of dung beetles in the Amazon rainforest, anew study suggests.
"With ongoing climate change, rising temperatures may push dung beetles beyond their physiological limits," said study lead authorKim Lea Holzmann of the University of Wurzburg in Germany, in an e-mail to USA TODAY.
The study was conducted in the Amazon region of Peru in 2022 and 2023. In the study, German researchers discovered that temperature is the decisive factor in the beetles' tolerable living conditions, and is far more important than food supply or soil moisture, for example.
Scientists say the insight is important: "Insects, including dung beetles, are fundamental components of ecosystems and form the base of many food webs," Holzmann said. "A loss in diversity could have cascading consequences on other groups, such as animals feeding on them."
What did the study find?
"We studied the populations [of dung beetles] at altitudes of 250 to 3,500 metres above sea level," said Holzmann, in a statement. "Unexpectedly, the number of dung beetle species fell rapidly between 250 and 500 metres above sea level."
The reason for this: At an altitude of 500 metres, the temperatures are in a range that is ideal for the beetles, while the higher temperatures in the lowlands lead to heat stress.
In turn, diversity fell at the higher, colder altitudes.
In total, the research team collected almost 5,000 dung beetles in pitfall traps, which they loaded with dung, fruit and carrion as bait.
Advertisement
As a result of the temperature increases, "species may be forced to shift to higher elevations to escape heat. However, this upward movement reduces available habitat and can lead to biodiversity loss across large areas, with cascading effects on food webs and ecosystem functioning."
Why do scientists care about dung beetles?
In addition to their role in the food web, dung beetles also play a key role as recyclers by breaking down animal dung and returning nutrients to the soil, Holzmann said. "This process improves soil fertility, supports plant growth, and enhances overall ecosystem productivity.
"By removing dung, they also reduce breeding sites for parasites and disease-causing organisms, helping to limit the spread of diseases."
Why study dung beetles? Are they endangered?
Besides their important role in ecosystems, dung beetles are an excellent model group for ecological research because their biology and ecology are relatively well understood, Holzmann said. "This makes them a valuable study system. They can be sampled using standardized trapping methods worldwide, since they are easily attracted to dung and carrion, which allows for comparable data across different regions."
In addition, dung beetles are highly sensitive to environmental disturbances such as habitat loss, land-use change, and climate shifts. Because of this sensitivity, they serve as strong bioindicators, meaning changes in their communities can reflect broader ecosystem changes.
"While not all dung beetle species are endangered, some are declining locally due to these pressures, making them important organisms to monitor."
The "methodology used in the study and the findings are sound," according toUniversity of Maryland tropical forest and biodiversity ecologist Juanita Choo, who was not part of the study. "Their findings that dung beetle diversity peaks at intermediate temperatures and falls off at extremes fits well with what we know about thermal limits of insects," Choo said.
She added that "critically, lowland beetles are already living near their upper heat tolerance limits, leaving little buffer for further warming."
Doyle Rice is a national correspondent for USA TODAY, with a focus on weather and climate.
This article originally appeared on USA TODAY:Climate change may be worsening life for dung beetles
