Intraguild predation by a biocontrol predator is reduced at lower temperatures

Abstract

Generalist predators play important roles in ecosystems by consuming various prey types. Despite this, predation studies often focus on a predator's most consumed prey, with limited attention given to predation on less common prey. In addition, despite increased temperature variability under climate change, it is unclear how predator foraging is affected by colder temperatures. Here, we examine the functional response of the generalist wolf spider Hogna baltimoriana on Hippodamia convergens ladybeetle larvae at an ambient and two colder temperatures. In agroecosystems, both wolf spiders and ladybeetles can act as biocontrol predators of pest species and may engage in intraguild predation, yet ladybeetles appear to be uncommon in wild wolf spiders' diets. We provide evidence of intraguild predation by H. baltimoriana on H. convergens across cold temperatures but find that the likelihood of this spider foraging on H. convergens larvae is reduced at lower temperatures and with a lower larva density. We further show that colder temperatures reduce space clearance rate, resulting in decreased foraging rates at low prey densities. Our results have important implications for biocontrol programs and our understanding of predator-prey interactions under climate change, and we highlight the need for functional responses to be evaluated on less commonly consumed prey.