A Test of Temporal Variation in Risk and Food Stimuli on Behavioral Tradeoffs in the Rusty Crayfish,Orconectes rusticus: Risk Allocation and Stimulus Degradation

Abstract

The effects of temporal variation in exposure to predation risk on behavioral tradeoffs were tested in the rusty crayfish, Orconectes rusticus. Based on the risk allocation hypothesis, we predicted that increasing the frequency of encounter with predation risk would yield increasing responses to a food stimulus in the presence of both a risk stimulus and a food stimulus. Crayfish were exposed to risk every 12 h, every 6 h, or left undisturbed for 24 h prior to testing. The risk stimuli used were a plain water control, snapping turtle (Chelydra serpentina) cue, and conspecific alarm cue. After 24 h of conditioning, the crayfish were exposed to a combination of risk cue and food cue. The behavioral responses of the crayfish were recorded for 5 min immediately following the introduction of the cues and again for 5 min, 1 h after stimulus exposure. The crayfish were observed at the two times to determine how their responses to the combination of risk and food cues changed over time. The responses of the crayfish were significantly influenced by stimulus treatment, time, and the interaction of time and stimulus treatment. Further analysis indicated that responses to the stimulus treatments changed differently over time. Immediately after exposure, the crayfish were more active in the control and snapping turtle treatments than in the conspecific alarm treatment. The high levels of activity initially observed in the control and snapping turtle treatments waned over time, such that the behaviors recorded 1 h after exposure were not significantly affected by stimulus treatment. Neither frequency nor the interactions of frequency with stimulus and/or time significantly affected crayfish behavior. The results of this study did not support the risk allocation model and contrast with results from similar work on the virile crayfish, Orconectes virilis.

Fixed vs. Random Temporal Predictability of Predation Risk: An Extension of the Risk Allocation Hypothesis

“…The results of these studies often show only partial support for the RAH model (Mirza et al. 2006; Pecor & Hazlett 2006; Slos & Stoks 2006). In one study, Foam et al.…”

Predator recognition of chemical cues in crayfish: diet and experience influence the ability to detect predation threats

“…Information about potential predation threat is extracted from the sensory landscape primarily in the form of two distinct classes of stimuli: alarm cues and predatory cues (i.e., kairomones) (Schoeppner & Reylea, 2009). In response to both of these cues, prey exhibit a large range of changes including changes in life history, morphology, behaviour, or even their physiology (Brönmark & Miner, 1992;Chivers & Smith, 1998;Peacor & Hazlett, 2006;Ferrari et al, 2009;Dalesman & Rundle, 2010). Within the aquatic realm, light and mechanical cues are limited in their spatial and temporal distribution and many aquatic animals use chemical stimuli to extract information about predatory threats (Kats & Dill, 1998;Wisenden, 2000).…”

Circadian rhythm does not affect responses to chemical cues in the red swamp crayfish,Procambarus clarkii

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