Weather anomalies are keeping insects active longer
As Earth's climate continues to warm, extreme and anomalous weather events are becoming more common. But predicting and analyzing the effects of what is, by definition, an anomaly can be tricky.
Scientists say museum specimens can help. In the first study of its kind, published in Nature Communications Biology, researchers at the University of Florida used natural history specimens to show that unseasonably warm and cold days can prolong the active period of moths and butterflies by nearly a month.
"Careful thinking about how organisms actually experience climate change allows for deeper biological insights, and can open up important new research directions"
"The results are not at all what we expected," said lead author Robert Guralnick, curator of biodiversity informatics at the Florida Museum of Natural History. The research was supported by the U.S. National Science Foundation.
Most studies view climate change and its consequences through a lens of average temperature increases. As temperature goes up over time, the plants and animals in a particular region become active earlier in the spring, delay dormancy until later in the fall and slowly shift their ranges to align with the climate in which they're best suited to survive.
Erratic weather adds a layer of complexity to these patterns, with unknown consequences that erect an opaque screen ahead of scientists attempting to predict the future of global ecosystems.
"There had been hints in the scientific literature that weather anomalies can have cumulative effects on ecosystems, but there wasn't anything that directly addressed this question at a broad scale," Guralnick said.
The results of the study are unequivocal. Unusually warm and cold weather has significantly altered insect activity to a greater extent than the average increase in global temperature for the last several decades.
The location and timing of extreme weather events influenced how insects responded. In higher latitudes, warm days in winter meant moths and butterflies became active earlier in the spring. Unusually cold days kept insects at all latitudes active longer, and the combination of exceptionally high and low temperatures had the strongest effect.
"Careful thinking about how organisms actually experience climate change allows for deeper biological insights, and can open up important new research directions," said Jeremy Wojdak, a program director in NSF's Division of Environmental Biology.