Asymmetrical effects of temperature on stage‐structured predator–prey interactions

Abstract

Warming can impact consumer–resource interactions through multiple mechanisms. For example, warming can both alter the rate at which predators consume prey and the rate prey develop through vulnerable life stages. Thus, the overall effect of warming on consumer–resource interactions will depend upon the strength and asymmetry of warming effects on predator and prey performance. Here, we quantified the temperature dependence of both (a) density‐dependent predation rates for two dragonfly nymph predators on a shared mosquito larval prey, via the functional response, and (b) the development rate of mosquito larval prey to a predator‐invulnerable adult stage. We united the results of these two empirical studies using a temperature‐ and density‐dependent stage‐structured predation model to predict the effects of temperature on the number of larvae that survive to adulthood. Warming accelerated both larval mosquito development and increased dragonfly consumption. Model simulations suggest that differences in the magnitude and rate of predator and prey responses to warming determined the change in magnitude of the overall effect of predation on prey survival to adulthood. Specifically, we found that depending on which predator species prey were exposed to in the model, the net effect of warming was either an overall reduction or no change in predation strength across a temperature gradient. Our results highlight a need for better mechanistic understanding of the differential effects of temperature on consumer–resource pairs to accurately predict how warming affects food web dynamics. A free plain language summary can be found within the Supporting Information of this article.

Functional response of Harmonia axyridis preying on Acyrthosiphon pisum nymphs: the effect of temperature

“…On the other hand, the temperature change did not change the type of functional response for predators, Scymnus levaillanti Mulsant, Adalia bipunctata L. and Cycloneda sanguinea (L.) (Coleoptera: Coccinellidae) preying on Aphis gossypii Glover and Myzus persicae (Sulzer) (Hemiptera: Aphididae), despite improved prey killing/handling abilities at higher temperatures 19 , 23 . This suggests differential effects of temperature on prey-predator pairs, probably for species‐specific differences in their sensitivity to temperature and hunting behaviour 24 , 25 . A large body of literature is directed towards understanding the consequence of warming on food webs and stability 26 , 27 .…”

Thermal asymmetries influence effects of warming on stage and size-dependent predator-prey interactions

“…Another example is that of Arctic mosquitoes, in which warming resulted in more rapid larval development and an increased attack rate by dytiscid predators, but in this case prey outpaced the predators, and warming resulted in increased prey survival (Culler et al 2015). Similar results were found with mosquitos and dragonfly larvae in North Carolina, though the increased predation rate of one dragonfly predator was much less than another (Davidson et al 2021).…”

“…Our modelling thus provides specific predictions for how we expect consumer impact on prey densities to change with warming depending on specific thermal traits of predators and prey. Previous work has found that prey survival may increase or decrease with warming (e.g., Culler et al 2015; Pepi et al 2018; Davidson et al 2021) without providing specific insight into the factors which might cause a specific interaction to change one way or the other.…”

“…Warming can cause changes in equilibria and stability of predator-prey dynamics due to differences in temperature-dependence of predator and prey biological rates (Vasseur and McCann 2005; Uszko et al 2017). Important changes to predator-prey dynamics may arise due to asymmetries in the thermal responses of predators and prey (Dell et al 2014; Culler et al 2015; Pepi et al 2018; Davidson et al 2021). A thermal asymmetry here refers to differences in thermal optima or thermal sensitivity that result in differential responses of predators and prey to changing temperature (Dell et al 2014; Pepi et al 2018).…”

“…Previous work has examined the consequences of thermal asymmetries in stage or size-dependent predation in a single specific system or using demographic models that represent only a single-generation (i.e., with no births or deaths; Culler et al 2015; Pepi et al 2018; Davidson et al 2021). In the present work, we develop a multigenerational theoretical population model to examine the asymptotic effects of thermal asymmetries on stage or size-dependent predator-prey interactions.…”