Influence of prey body characteristics and performance on predator selection

Abstract

At the time of settlement to the reef environment, coral reef fishes differ in a number of characteristics that may influence their survival during a predatory encounter. This study investigated the selective nature of predation by both a multi-species predator pool, and a single common predator (Pseudochromis fuscus), on the reef fish, Pomacentrus amboinensis. The study focused on the early post-settlement period of P. amboinensis, when mortality, and hence selection, is known to be highest. Correlations between nine different measures of body condition/performance were examined at the time of settlement, in order to elucidate the relationships between different traits. Single-predator (P. fuscus) choice trials were conducted in 57.4-l aquaria with respect to three different prey characteristics [standard length (SL), body weight and burst swimming speed], whilst multi-species trials were conducted on open patch reefs, manipulating prey body weight only. Relationships between the nine measures of condition/performance were generally poor, with the strongest correlations occurring between the morphological measures and within the performance measures. During aquaria trials, P. fuscus was found to be selective with respect to prey SL only, with larger individuals being selected significantly more often. Multi-species predator communities, however, were selective with respect to prey body weight, with heavier individuals being selected significantly more often than their lighter counterparts. Our results suggest that under controlled conditions, body length may be the most important prey characteristic influencing prey survival during predatory encounters with P. fuscus. In such cases, larger prey size may actually be a distinct disadvantage to survival. However, these relationships appear to be more complex under natural conditions, where the expression of prey characteristics, the selectivity fields of a number of different predators, their relative abundance, and the action of external environmental characteristics, may all influence which individuals survive.

Impact des coupes forestières sur l'écologie des jeunes stades de vie chez la perchaude (Perca flavescens) :

“…Litvak & Leggett 1992, Pépin et al 1992, Gleason & Bengtson 1996a, 1996b, Takasuka et al 2004a, 2004b, Gagiiano et al 2007, Nishimura et al 2007, Takasuka et al 2007a, Holmes & McCormick 2009, we also observed the unequivocal existence of selection for slow growth in the yellow perch populations of lakes Cut-1, Cut-3…”

“…Cependant, d'autres travaux ont montré que les survivants étaient plutôt les individus à croissance lente d'une cohorte (e.g. Litvak & Leggett 1992, Pépin et al 1992, Gleason & Bengtson 1996b, 1996a, Takasuka et al 2004a, 2004b, Nishimura et al 2007, Takasuka et al 2007a, Holmes & McCormick 2009). Enfin, certaines études ont observé que la survie était indépendante de la croissance (e.g.…”

“…Litvak & Leggett 1992, Pépin et al 1992, Gleason & Bengtson 1996b, 1996a, Takasuka et al 2004a, 2004b, Nisbimura et al 2007, Takasuka et al 2007a, Holmes & McCormick 2009). La sélection pour la croissance lente dispose aussi de plusieurs arguments valables.…”

“…However, many studies shown that the survivors were rather the slow-growing members of a cohort (e.g. Litvak & Leggett 1992, Pépin et al 1992, Gleason & Bengtson 1996a, 1996b, Takasuka et al 2004a, 2004b, Nishimura et al 2007, Takasuka et al 2007a, Holmes & McCormick 2009. Furthermore, other studies indicated that the survivors could also be randomly selected, without preference between fast-or slow-growing individuals at the end of the larval stage (e.g.…”

Behavioural mediation of the costs and benefits of fast growth in a marine fish

“…Why this mortality was positively selective is not known; it may simply reflect predator choice. Holmes & McCormick (2009) have shown that when simultaneously offered large and small prey items, Pseudochromis fuscus, one of the major predators of newly settled P. amboinensis, preferentially selects large recruiting fishes, presumably as an optimally evolved foraging tactic (Holmes & McCormick 2009). These predators are abundant on the shallow inshore reefs of Lizard Island ) adjacent to our patch reefs.…”