Trait‐mediated functional responses: predator behavioural type mediates prey consumption

Abstract

Summary1. The predator functional response (i.e. per capita consumption rate as a function of prey density) is central to our understanding of predator-prey population dynamics. This response is behavioural, depending on the rate of attack and time it takes to handle prey. 2. Consistent behavioural differences among conspecific individuals, termed behavioural types, are a widespread feature of predator and prey populations but the effects of behavioural types on the functional response remain unexplored. 3. We tested the effects of crab (Panopeus herbstii) behavioural type, specifically individual activity level, on the crab functional response to mussel (Brachidontes exustus) prey. We further tested whether the effects of activity level on the response are mediated by the presence of toadfish (Opsanus tau) predation threat in the form of waterborne chemical cues known to reduce crab activity level. 4. The effects of crab activity level on the functional response were dependent on crab body size. Individual activity level increased the magnitude (i.e. slope and asymptote) of the type II functional response of small crabs, potentially through an increase in time spent foraging, but had no effect on the functional response of large crabs. Predation threat did not interact with activity level to influence mussel consumption, but independently reduced the slope of the type II functional response. 5. Overall, this study demonstrates size-specific effects of a behavioural type on a predatorprey interaction, as well as a general pathway (modification of the functional response) by which the effects of individual behavioural types can scale up to influence predator-prey population dynamics.

Consumer trait variation influences tritrophic interactions in salt marsh communities

“…S2). This positive effect of predators on Spartina suggests that changes in snail foraging rate due to direct or indirect predator effects are consistent across snail types (Kimbro 2012; Toscano and Griffen 2014). In contrast, the combination of snail trait variation and predator presence/absence strongly influenced Juncus height, density, and biomass.…”

A simulation-based method to compare the pest suppression potential of predators: A case study with spiders

“…Since natural assemblages have multiple prey species that are subjected to seasonal processes, key community-related concepts such as food preference and prey preference (Wise et al, 2006),behavioral differences among conspecifics (Toscano and Griffen, 2014), successional processes (Settle et al, 1996), intraguild competition and prey availability (Perkins et al, 2018) and predator-prey body size proportion (Shimazaki and Miyashita, 2005) can have implications for ecosystem functioning and stability and should also be considered within the context of functional response modeling.…”

Behavioral Hypervolumes of Predator Groups and Predator-Predator Interactions Shape Prey Survival Rates and Selection on Prey Behavior

“…Such variation is intriguing from an ecological standpoint because of its potential to change the outcome of a variety of processes, including population dynamics (Pruitt 2013), range expansion/recession (Cote et al 2011; Fogarty et al 2011), trophic cascades (Griffen et al 2012; Toscano and Griffen 2014), community assembly (Pruitt and Modlmeier 2015; Royaute and Pruitt 2015), and even extinction risk. To date, these studies have tended to focus on single trait-outcome relationships.…”