The effect of temperature on growth and cannibalism in dragonfly larvae

Sammanfattning

Global climate change is likely to alter intraspecific competition due to changes in growth and development. An extreme form of intraspecific interaction is cannibalism which occurs in ectotherms such as dragonflies. This study investigates the effect of temperature on growth and cannibalism in larvae of the dragonfly Sympetrum vulgatum, using a laboratory experiment where larvae were raised at three different temperatures (20°C, 23°C and 26°C) for four weeks. The results show that higher temperatures increase levels of cannibalism. This pattern can be driven by higher behavioural activity and movement, leading to more encounters between individuals. Warming also accelerates growth rate of individuals both directly and indirectly through cannibalism as cannibals gain more food per capita and additional nutrients from the victims eaten. Rising temperatures, leading to increased cannibalism can have a chain of effects on food webs in ecosystems.