Disturbance cues as a source of risk assessment information under natural conditions

Abstract

Disturbance cues are released by stressed or disturbed prey prior to a predator attack and convey useful risk assessment information regarding local threats. While studies have shown that disturbance cues may be important early on within the predation sequence (prior to an attack), their role in predator–prey interactions remains relatively overlooked by ecologists. Critically, experimental studies examining disturbance cues, especially among prey fishes, have been conducted primarily under laboratory or semi‐natural conditions. Here, we tested the prediction that disturbance cues function as sources of risk assessment information in situ. We exposed Trinidadian guppies, in two natural populations differing in predation risk, to a model predator paired with stream water or the disturbance cue collected from guppies from either a high‐ or low‐predation risk population. We found that the predator inspection response of guppies to disturbance cues depends on the level of risk of both the focal and the cue source population. Guppies from both populations exhibited increased latencies to inspect, lower inspection rates and reduced inspecting group sizes towards the model paired with conspecific disturbance cues versus a stream water control. Interestingly, guppies of both populations showed evidence of higher perceived predation risk towards the disturbance cues collected from high‐predation risk donors compared to low‐predation risk donors. Our results support the hypothesis that disturbance cues function as a source of information used by prey fish in the assessment of predation risk and provide the first evidence of disturbance cue function under fully natural conditions.

Chemical disturbance cues in aquatic systems: a review and prospectus

“…Most studies have involved freshwater species, but there are also a few marine examples (e.g., Olivotto et al 2002, Fulton et al 2017). One study verified the response to disturbance cues in natural populations of Trinidadian guppies (Goldman et al 2020a) and, to date, this is the only disturbance cue study (fish or not) under fully natural conditions. When a novel heterospecific model was paired with disturbance cues, rather than a stream water control, guppies inspected at lower rates and in smaller groups, while also taking longer to do so.…”

“…However, the background risk exposures for receivers and donors were not additive (i.e., only one was required to elicit the maximum response) (Bairos-Novak et al 2017). Similarly, guppies exposed to high background risk responded more strongly to disturbance cues from high-risk donors compared with low-risk donors, whereas low-risk receivers did not discriminate (Goldman et al 2020a). This same pattern was also observed in guppies from natural populations experiencing variable background predation risk (Goldman et al 2020a), as well as in situ (Goldman et al 2020b).…”

“…We recommend that researchers use disturbance cues as rapidly as possible until the longevity of effectiveness is confirmed in their study species. We know of two studies that used frozen disturbance cues (at approximately −20°C), both finding that the cues were at least partially effective when frozen shortly after release and then used shortly after thawing (Goldman et al 2020a; I. A. E. Rivera-Hernández et al, unpublished manuscript).…”

Behavioural Stress Propagation in Benthic Invertebrates Caused by Acute pH Drop-Induced Metabolites

“…Such mechanisms of chemical communication also occur in invertebrates, as evidenced by the reduced out-ofburrow activity of the marine polychaete Alitta virens exposed to damaged conspecifics (Watson et al, 2005;Ende et al, 2017). Disturbance cues refer to chemicals that may be stored in gill epithelium or urine, and are released voluntarily or involuntarily by disturbed or stressed prey, to induce early antipredator responses in recipients to anticipate potential threats (Bairos-Novak et al, 2017;Goldman et al, 2020a). The central role of chemical communication in the aquatic environment and the recent evidence of its impairment by ocean acidification pinpoints the need for a deeper understanding of such potential environmental modulation of chemical signalling (Chivers et al, 2013).…”

Behavioural stress feedback loops in benthic invertebrates caused by pH drop-induced metabolites

“…Such mechanisms of chemical communication also occur in invertebrates, as evidenced by the reduced out-of-burrow activity of the marine polychaete Alitta virens exposed to damaged conspecifics (Watson et al, 2005; Ende et al, 2017). Disturbance cues refer to chemicals that may be stored in gill epithelium or urine, and are released voluntarily or involuntarily by disturbed or stressed prey, to induce early antipredator responses in recipients to anticipate potential threats (Bairos-Novak et al, 2017; Goldman et al, 2020a). The central role of chemical communication in the aquatic environment and the recent evidence of its impairment by ocean acidification pinpoints the need for a deeper understanding of such potential environmental modulation of chemical signalling (Chivers et al, 2013).…”