LB 9-107 - Predator-prey interactions in a warming world: warmer and more seasonal climates decrease predation effect

Background/Question/Methods:

Thermal tolerance mismatch within predator-prey systems may have profound effects on species population abundances and geographical distributions. Despite increasing attention to the impacts of climate change on predator-prey interactions, few studies have evaluated how thermal tolerance mismatches between interacting species affect species' response to a changing climate. To examine the generalized responses of a predator-prey system to climate change, we construct a biologically detailed stage-structured population dynamic model of interactions between ladybird beetles and aphids. We explore the model's dynamics across the entire feasible parameter space of mean temperature and seasonality within the global. We use nine hypothetical ladybirds (which have different critical thermal minima and maxima) and one aphid to form nine pairs of interacting species which have all the possible qualitative thermal tolerance mismatches. We simulate nine different climate scenarios (one current climate scenario and eight future climate scenarios) by altering the mean temperature and seasonality across the entire parameter space. Then, we measure the climate and predation effect on affecting aphid population for different predator-prey thermal tolerance mismatch cases and different climate scenarios to gain insight into how these thermal sensitivities affect the interacting species’ responses to climatic change.

Results/Conclusions:

Our results show that, under the climate condition, when ladybird beetles are more thermotolerant than the aphids (no matter better cold or heat tolerance), the population abundance of ladybirds will increase with no doubt. The impact of predator-prey interaction will also be wider and stronger, making the prey population better controlled.

Among different climate change scenarios, warmer and more seasonal climates decrease the predation effect regardless of thermal tolerance mismatch. With global warming, warmer and more seasonal climates will become less favourable for the aphid and ladybird populations.

Comparing the climate and predation effect on affecting aphid population, our results indicate predation plays a dominant role in decreasing aphid population abundance in the regions with warmer and less seasonal climates. These regions are wider if predators are more thermotolerant than prey. Predation will have weaker effects in more regions if the climate becomes warmer and more seasonal. Our study highlights the importance of understanding the complex interplay between climate change and species interactions.