Context-dependent effects of temperature and community complexity on trophic interaction strength in a mite community

Abstract

Both temperature and community complexity are known to affect trophic interaction strength (TIS), but whether their effect is additive or not is as yet an open question. Here we used a 2-predator/3-prey system consistently occurring in avocado orchards to explore the effects of increasing warming and community complexity on the strength of predator:prey trophic interactions. The two predator species differed in their diet breath (a carnivore and an omnivore) and the prey types included a herbivore, heterospecific juvenile predators, and/or pollen. Overall, analyses revealed multiplicative effects of community complexity and both temperature and predator diet breath on the net predator:prey(s) TIS. Indeed, warming led to increased TIS in the community with omnivore as top predator, but only in absence of its preferred food source. When the carnivore was the top predator, in contrast, higher temperatures led to TIS being more negative, but only for the IGprey. We conclude that sources of context dependence in specific systems need to be identified to unveil effects of warming on communities.