Predator avoidance behavior in the pea aphid: costs, frequency, and population consequences

Abstract

Induced prey defenses can be costly. These costs have the potential to reduce prey survival or reproduction and, therefore, prey population growth. I estimated the potential for predators to suppress populations of pea aphids (Acyrthosiphon pisum) in alfalfa fields through the induction of pea aphid predator avoidance behavior. I quantified (1) the period of non-feeding activity that follows a disturbance event, (2) the effect of frequent disturbance on aphid reproduction, and (3) the frequency at which aphids are disturbed by predators. In combination, these three values predict that the disturbances induced by predators can substantially reduce aphid population growth. This result stems from the high frequency of predator-induced disturbance, and the observation that even brief disturbances reduce aphid reproduction. The potential for predators to suppress prey populations through induction of prey defenses may be strongest in systems where (1) predators frequently induce prey defensive responses, and (2) prey defenses incur acute survival or reproductive costs.

Personality variation in a clonal insect: The pea aphid,Acyrthosiphon pisum

“…An individual's response to a predator threat can have substantial fitness consequences: the costs of staying on a plant can be high since dropping significantly reduces the risk of being predated by a coccinellid predator (Niku, 1976;Francke et al, 2008). At the same time, dropping off a plant entails costs as well (e.g., risk of desiccation, loss of foraging opportunity, risk of ground-predation; Roitberg & Myers, 1978;Dill et al, 1990;Losey & Denno, 1998b;Nelson, 2007). Therefore, if individuals show consistent behavioral differences in their escape responses, fitness consequences are expected to be high.…”

Model complexity affects transient population dynamics following a dispersal event: a case study with pea aphids

“…Aphid populations consist of winged (alatae) and unwinged (apterae) morphs; if feeding conditions become unfavorable (e.g., low host plant quality or crowded conditions) an increased proportion of winged morphs are born, which disperse to new habitats (Dixon 1985). Wingless morphs usually remain in the vicinity of their birth location unless they are disturbed (e.g., by predators; Nelson andRosenheim 2006, Nelson 2007), thus single plants may host a few generations of aphids. Aphids have five distinct lifehistory stages: four juvenile instars and one adult stage Hogg 1984, 1985), a fact that makes them ideal candidates for stage-structured models.…”

Consumptive and nonconsumptive effect ratios depend on interaction between plant quality and hunting behavior of omnivorous predators

“…Nonconsumptive effects can have far‐reaching impacts on trophic cascades (Beckerman, Uriarte, & Schmitz, 1997; Trussell, Ewanchuk, & Bertness, 2003), ecosystem functions (Matassa & Trussell, 2011; Schmitz, Grabowski, & Peckarsky, 2008), and often equal or exceed the effects of consumption (Preisser, Bolnick, & Benard, 2005; Schmitz, Krivan, & Ovadia, 2004). Nonconsumptive effects can increase prey vulnerability to other mortality factors (McCauley & Rowe, 2011) or generate physiological stress, resulting in energetic costs with a cascading negative impact on prey reproduction (Creel, Winnie, & Christianson, 2009; Nelson, 2007; Nelson, Matthews, & Rosenheim, 2004). Lower reproduction due to predators caused by, for example, mating interruption (Travers & Sih, 1991), higher conspicuousness of males attracting females (Uzendoski, Maksymovitch, & Verrell, 1993), or changes in prey behavior that result in lower weight gain or poorer provisioning of progeny (Harfenist & Ydenberg, 1995) should represent the strongest nonconsumptive effects as they reduce prey fitness.…”