Data from: Cannibalism and activity rate in larval damselflies increase along a latitudinal gradient as a consequence of time constraints

Background: Predation is ubiquitous in nature. One form of predation is cannibalism, which is affected by many factors such as size structure and resource density. However, cannibalism may also be influenced by abiotic factors such as seasonal time constraints. Since time constraints are greater at high latitudes, cannibalism could be stronger at such latitudes, but we know next to nothing about latitudinal variation in cannibalism. In this study we examined cannibalism and activity in larvae of the damselfly Lestes sponsa, along a latitudinal gradient across Europe. We did this by performing a laboratory study where we raised larvae from the eggs stage and manipulated temperature and photoperiod. Results: We found that the more seasonally time-constrained populations in northern latitudes and individuals subjected to greater seasonal time constraints exhibited a higher level of cannibalism. We also found that activity was higher at north latitude conditions, and thus correlated with cannibalism, suggesting that this behaviour mediates higher levels of cannibalism in time-constrained animals. Conclusions: Our results go counter to the classical latitude-predation pattern which predicts higher predation at lower latitudes, since we found that predation was stronger at higher latitudes. The differences in cannibalism might have implications for population dynamic along the latitudinal gradients, but further experiments are needed to explore this.