Chemical Predator Inspection in a Characin Fish (Hemigrammus erythrozonus,Characidae, Ostariophysi): The Effects of Mixed Predator Diets

Abstract

Many prey organisms will approach (inspect) potential predators, primarily to assess local risk of predation. It has been demonstrated that Ostariphysan prey fishes can detect conspecific alarm pheromones in the diet of potential predators and use this chemical information to reduce their risk of predation while still gaining significant benefits associated with predator inspection. We conducted the current study to examine the possible effects of mixed diets on the use of these chemical predator diet cues during inspection visits. Shoals of four glowlight tetras (Hemigrammus erythrozonus) were exposed to Jack Dempsey cichlids (Cichlasoma octofaciatum) which had been fed diets consisting of: 100% tetras (with alarm pheromone); 75% tetra, 25% swordtail (Xiphophorus helleri, which lack a recognizable alarm pheromone); 25% tetra, 75% swordtail; or 100% swordtails. Tetras significantly increased their anti‐predator behaviour in response to predators fed 100% tetra or the two mixed predator diets, but not when exposed to predators fed a 100% swordtail diet. Likewise, we observed significant differences in inspection behaviour. Tetras took longer to initiate an inspection, inspected in smaller groups and directed a greater proportion of inspection visits towards the tail region of the predator when it had been fed 100% tetra or either of the two mixed prey diets. We found no significant differences in either anti‐predator or inspection behaviour among the three diet treatments containing tetras. These data strongly suggest that glowlight tetras are capable of detecting relatively small amounts of conspecific alarm pheromone in the diet of potential predators and that they modify their behaviour based on the presence or absence of these cues.

Divergent walleye (Sander vitreus)-mediated inducible defenses in the centrarchid pumpkinseed sunfish (Lepomis gibbosus)

“…Aside from the crucian carp ( Carassius carassius ), there are few examples of predator‐induced morphological responses in fishes (Brönmark & Miner, 1992; Brönmark & Pettersson, 1994). This is surprising, given that many species of fishes, including L. gibbosus , elicit inducible antipredator behavioural responses to predator cues (Mathis & Smith, 1993; Brown, Chivers & Smith, 1995; Brown & Brennan, 2000; Brown, Golub & Plata, 2001; Chivers et al ., 2001; Smith & Belk, 2001; Brown & Zachar, 2002; Mirza & Chivers, 2002; Leduc et al ., 2003; Marcus & Brown, 2003). The primary cues in fishes are alarm substances released from damaged conspecific skin tissue (Stabell & Lwin, 1997; Chivers & Smith, 1998).…”

Temporal variation in behavioral responses to dietary cues from a gape‐limited predator in tadpole prey: A test of the phylogenetic relatedness hypothesis

“…Dietary cues are important sources of information in aquatic systems, but because predators, generalists in particular, can forage on a range of resources in nature, prey are exposed to numerous dietary cues. Typically, responses should be tuned to the strongest cues, which could be assessed by the presence of conspecific or closely related heterospecific pheromones in predators’ diet (Brown & Zachar, ; Hoefler et al, ). If such cues are not available in the environment, prey may lack reliable information to effectively respond to predators.…”

“…Typically, responses should be tuned to the strongest cues, which could be assessed by the presence of conspecific or closely related heterospecific pheromones in predators' diet (Brown & Zachar, 2002;Hoefler et al, 2012). If such cues are not available in the environment, prey may lack reliable information to effectively respond to predators.…”

Impacts of longfin eels (Anguilla dieffenbachii) on the behaviour of common bullies (Gobiomorphus cotidianus) held in captivity

“…As longfin eels are largely ambush predators and use cover-like weed beds for concealment (Burnet 1969), avoidance of such areas, especially during the day, could reduce the likelihood of bullies being eaten. A number of studies on olfactory cues in fish have shown that prey species are often able to detect when the diet of a predator includes their own species (Brown & Zachar 2002;Brown 2003;Brown & Magnavacca 2003); it would be interesting to see whether bullies exhibit such a response -if bullies are able to do this, they might be less concerned by the presence of an eel when its odour (or odour of faeces) did not contain odour of their conspecifics. A number of studies on olfactory cues in fish have shown that prey species are often able to detect when the diet of a predator includes their own species (Brown & Zachar 2002;Brown 2003;Brown & Magnavacca 2003); it would be interesting to see whether bullies exhibit such a response -if bullies are able to do this, they might be less concerned by the presence of an eel when its odour (or odour of faeces) did not contain odour of their conspecifics.…”

“…Different day-and night-time habitat preferences are known for longfins with a much higher use of riffles during night (Jellyman & Sykes 2003) -whether common bullies show diel habitat shifts is unknown, but such shifts have been recorded from other native species including upland bullies (Davey et al in press) and nonmigratory galaxiids (Crow et al 2010). A number of studies on olfactory cues in fish have shown that prey species are often able to detect when the diet of a predator includes their own species (Brown & Zachar 2002;Brown 2003;Brown & Magnavacca 2003); it would be interesting to see whether bullies exhibit such a response -if bullies are able to do this, they might be less concerned by the presence of an eel when its odour (or odour of faeces) did not contain odour of their conspecifics. Given the relative indifference of bullies to the presence of an eel in the present study, it would be of interest to see whether larger longfin eels elicited a greater response.…”