Insects are struggling to cope with the higher temperatures caused by climate change and could be in danger of overheating.
According to a new study from Lund University in Sweden, their ability to reproduce would also be seriously impaired by increasing temperatures, even in northern areas of the world.
Insects are unable to control their own body temperature; instead, the temperature in their immediate environment is highly affected.
Researchers have studied two closely related species of dragonflies in Sweden in the current research.
The aim was to consider their robustness and capacity to withstand variations in temperature.
To investigate this, the researchers used a combination of fieldwork in southern Sweden and infrared camera technology (thermography), a technology that allows body temperature to be measured under natural conditions.
The survival rates and the reproductive success of dragonflies in their natural populations were then linked to this knowledge.
The results show that, at relatively low temperatures, the survival rate of these damselflies was high, 15 – 20 C °.
In comparison, the reproductive potential was higher, depending on the species, at temperatures between 20 and 30 C °.
“So there is a temperature-dependent conflict between survival on the one hand and the ability to reproduce on the other,” says Erik Svensson, a professor at the Lund University Department of Biology who led the research.
The study also demonstrates that dragonflies have a limited capacity to deal with stress related to heat.
Insects are cold-blooded invertebrates, so they rely on external sources to increase their body temperature, such as the sun or hot rocks.
Our findings show that even though they live far up in the northern hemisphere, cold-blooded animals may suffer from overheating and that their capacity to buffer their body temperature against increasing external temperatures is minimal.
The results also contradict a common hypothesis that the plasticity of animals, or the resilience of individuals, may enable them to survive in harsher environmental conditions, such as heat waves, says Erik Svensson.
Erik I. Svensson, Miguel Gomez-Llano, and John T. reference: “Selection on phenotypic plasticity favors thermal canalization”
Waller, Nov. 24, 2020, Proceedings of the National Academy of Sciences.DOI: 10.1073/pnas.2012454117