Climate change-related temperature swings leave insects vulnerable

Increasingly extreme swings in temperature may put some insects at higher risk than previously thought, according to a new study published today in the Proceedings of the Royal Society of London.

An international team of scientists tested the impact of temperature patterns on 38 species of insects and analyzed the results along with historic climate data and projections for 2050 to 2059. They found that when only the mean temperature rise is considered, insects flourished in the warmer environments. However, when accounting for the variation in highest and lowest temperatures, insects were negatively impacted.

“This study changes the way we think about climate change vulnerability of plants and animals,” says study co-author Mary O’Connor, an assistant professor in the University of British Columbia’s Dept. of Zoology.

“Until recently, we believed that tropical species were more at risk of extinction because generally they cannot tolerate increasing temperatures. We also thought that many plants and animals in colder climates like in Canada could better tolerate warming,” says O’Connor, who is also associate director of UBC’s Biodiversity Research Centre.

“But when we add changes in daily and annual temperature swings to the mix, species in colder climates are in no better shape to weather climate change.”

O’Connor adds that species such as the stable fly Stomoxys calcitran and Muscidifurax zaraptor, a wasp commonly used for biocontrol in Canada, are among the species that would not benefit from warming, contrary to previous predictions.

This study was led by Yale University’s Prof. David Vasseur and funded by the Canadian Institute for Ecology and Evolution and the National Center for Ecological Analysis and Synthesis. The international research team was co-led by O’Connor and Hamish Greig at the University of Maine. The UBC team also includes Zoology Assoc. Prof. Christopher Harley.