Do Experience and Body Size Play a Role in Responses of Larval Ringed Salamanders, Ambystoma annulatum, to Predator Kairomones? Laboratory and Field Assays

Abstract

Prey may experience ontogenetic changes in vulnerability to some predators, either because of changes in morphology or experience. If prey match their level of antipredator behavior to the level of predatory threat, prey responses to predators should reflect the appropriate level of threat for their stage of development. For larval salamanders, responses to predators may change with body size because larger larvae are less vulnerable to predation by gape‐limited predators or because fleeing responses by large salamanders may be more effective than for smaller salamanders. In a field experiment, small larval ringed salamanders, Ambystoma annulatum, responded to chemical stimuli (‘kairomones’) from predatory newts, Notophthalmus viridescens, with an antipredator response (decreased activity). Laboratory‐reared larvae decreased their activity following exposure to newt kairomones, indicating that larval ringed salamanders do not require experience with newts to recognize them as predators. In both experiments, larvae distinguished between chemical stimuli from newts and stimuli from tadpoles (non‐predators) and a blank control. In a third experiment, field‐caught (experienced) larvae showed a graded response to newt kairomones based on their body size: small larvae tended to decrease their activity while larger larvae showed no change or an increase in activity. This graded response was not observed for neutral stimuli, indicating that it is predator‐specific. Therefore, ringed salamander larvae exhibit threat‐sensitive ontogenetic changes in their response to chemical stimuli from predatory newts.

Fear is the mother of invention: anuran embryos exposed to predator cues alter life-history traits, post-hatching behaviour, and neuronal activity patterns

“…A decrease in tadpole activity after exposure to predator cues is consistent with an adaptive anti-predator response because dragonfly larvae can most probably detect and capture actively moving prey (Skelly, 1994;Mathis et al, 2003Mathis et al, , 2008. The contextual behavioural response of agile frog larvae to dragonfly kairomone might thus be, to a large extent, innate (Lima and Dill, 1990;Scheurer et al, 2007;Epp and Gabor, 2008), as control tadpoles displayed the typical anti-predator behaviour upon their first postnatal experience with the odour of the predator (Fig.…”

“…As larval anurans typically reduce their activity level when exposed to predator cues ('freezing behaviour'; Skelly, 1994;Mathis et al, 2003;Ferrari and Chivers, 2009), we predicted that treated tadpoles would show a lower baseline post-hatching activity than controls. In addition, we expected a differential contextual behavioural response according to embryonic experience, i.e.…”

Size-selectivity of predatory reef fish on juvenile prey

“…The idea that prey body size has a large influence on the outcome of predator-prey encounters is not new to the field of ecology (Litvak & Leggett 1992, Janzen 1993, Mathis et al 2003. The most common view amongst ecologists is that larger prey size conveys a universal survival advantage during such events (i.e.…”

Use of chemical cues in detection of conspecific predators and prey by newts, Notophthalmus viridescens

“…Decreased activity in response to predatory stimuli is a common antipredator response for amphibians (Stauffer & Semlitsch 1993) and other vertebrates (Downs 2002;Mirza & Chivers 2003). Although my study was a laboratory bioassay, decreased activity by larval salamanders in response to predatory stimuli also has been reported in natural habitats (Mathis et al 2003). Decreased activity in response to predatory stimuli can lower the risk of predation by decreasing the probability of detection (Azevedo-Ramos et al 1992;Skelly 1994).…”