How will climate impact the beetles that protect our crops?

In North America, nearly 2,000 species of ground beetles support crops by preying on insect pests and eating the seeds of bothersome weeds in the surrounding soil. A new study from Penn State has investigated what the future looks like for ground beetles in the face of climate change. 

The experts found that while some ground beetles will thrive under future conditions, others will struggle to survive. The difference depends on the beetles’ unique traits and habitats. 

“We know that climate change influences everything from coral reefs in the ocean to trees on land, but there’s less information available on how it affects insects,” said Professor Tong Qiu. “Ground beetles are everywhere – in your backyard, in your garden. They eat the pests and weed seeds that damage crops and are important food sources for birds. They are small insects, but they have large ecosystem impacts.”

Professor Qiu and his colleagues set out to investigate how ground beetles will respond to environmental changes based on raw data collected across the continent of North America. The team examined species as a group based on their unique traits such as preferred habitat, body size, and whether they fly, burrow, climb or run.

“We synthesized the abundance and trait data for 136 species from the National Ecological Observatory Network (NEON) and additional raw data from studies across North America with remotely sensed habitat characteristics in a generalized joint attribute model,” wrote the study authors.

“Combined Light Detection and RAnging (LiDAR) and hyperspectral imagery were used to derive habitat at a continental scale. We evaluated climate risks on the joint response of species and traits by expanding climate velocity to response velocity given habitat change.”

The analysis revealed that less mobile beetle species that do not fly may decline over time. However, the researchers explained that habitat conservation can mitigate the effects of climate change and reverse the trend in some areas. 

“We found that nonflying carnivores, which are critical pest control agents, are more likely to decline over time in a warmer, dryer climate,” said Professor Qiu. “If you have fewer carnivores, you’ll have more of the pests that can impact agriculture.”

According to the researchers, habitat conditions can play a large role in beetle population change and can actually reverse the trend. Professor Qiu noted that some habitats, such as those with dense understory plants and fallen tree logs, offer important microclimate conditions that help to mitigate the effects of climate change.

“We hope conservation biologists will use the information in this paper and the online map that we created to better manage habitats for insects in general,” said Professor Qiu. “Ground beetles are very beneficial to ecosystems, but they’re largely invisible to the average person. In this paper we’re showing the broad impacts they have on whole communities in forested and agricultural ecosystems.”

The study is published in the journal Global Ecology and Biogeography.

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By Chrissy Sexton, Earth.com Editor

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