The Combined Effects of Warming and Body Size on the Stability of Predator-Prey Interactions

Abstract

Environmental temperature and body size are two prominent drivers of predation. Despite the ample evidence of their independent effects, the combined impact of temperature and predator-prey body size ratio on the strength and stability of trophic interactions is not fully understood. We experimentally tested how water temperature alters the functional response and population stability of dragonfly nymphs (Cordulegaster boltonii) feeding on freshwater amphipods (Gammarus pulex) across a gradient of their body size ratios. Attack coefficients were highest for small predators feeding on small prey at low temperatures, but shifted toward the largest predators feeding on larger prey in warmer environments. Handling time appeared to decrease with increasing predator and prey body size in the cold environment, but increase at higher temperatures. These findings indicate interactive effects of temperature and body size on functional responses. There was also a negative effect of warming on the stability of predator and prey populations, but this was counteracted by a larger predator-prey body size ratio at higher temperatures. Here, a greater Hill exponent reduced feeding at low prey densities when predators were much larger than their prey, enhancing the persistence of both predator and prey populations in the warmer environment. These experimental findings provide new mechanistic insights into the destabilizing effect of warming on trophic interactions and the key role of predator-prey body size ratios in mitigating these effects.

Spatial insurance against a heatwave differs between trophic levels in experimental aquatic communities

“…There has been mounting evidence that the impacts of warming critically depend on the trophic level (and associated traits such as body size) of organisms, driven by their different physiological constraints and changes in the strength of trophic interactions (Kratina et al, 2022; Petchey et al, 1999; Shurin et al, 2012). For instance, increased metabolic demands of ectothermic consumers can result in higher feeding rates, resulting in stronger top‐down control (Brown et al, 2004; Romero et al, 2018; Zhang et al, 2020).…”

Temperature fluctuation alters optimal predator community composition for anticipated biological control

“…In this manuscript we expand on that work by adding temperature-dependence in predator interaction rates. A recent study on dragonfly predators suggests that the change of attack rate and handling time with temperature depends on the body size of the predator, and that this has consequences for long-term ecosystem stability (Kratina et al, 2022). In many agricultural ecosystems with frequent human interference, predator-prey interactions are unlikely to stabilize.…”

Changes in prey body size differentially reduces predation risk across predator and prey abundances

“…not handling prey) at any given point in time. The shapes of functional responses are influenced by multiple behavioral and morphological traits of both predators and prey (Kratina et al 2010(Kratina et al , 2022 and Paramecium induce multiple anti-predator defences (Kratina et al 2010). In this study we focus on a single prey trait (body width) as our goal was to unpack how changes in one trait combine with differences in predator abundance to influence functional responses to better understand how functional responses alter predator-prey dynamics.…”