Are all signals the same? Ontogenetic change in the response to conspecific and heterospecific chemical alarm signals by juvenile green sunfish (Lepomis cyanellus)

Response to conspecific and heterospecific alarm cues by pumpkinseeds in simple and complex habitats: field verification of an ontogenetic shift

“…It has recently been demonstrated that juvenile centrarchids also undergo a similar ontogenetic shift in their response to damage-released chemical alarm cues (Brown et al, 2001a(Brown et al, , 2002Golub & Brown, 2003). Damage-released chemical alarm cues are found in a wide range of freshwater fishes (Smith, 1992;Chivers & Smith, 1998), including centrarchids Golub & Brown, 2003;Marcus & Brown, 2003).…”

“…It has recently been demonstrated that juvenile centrarchids also undergo a similar ontogenetic shift in their response to damage-released chemical alarm cues (Brown et al, 2001a(Brown et al, , 2002Golub & Brown, 2003). Damage-released chemical alarm cues are found in a wide range of freshwater fishes (Smith, 1992;Chivers & Smith, 1998), including centrarchids Golub & Brown, 2003;Marcus & Brown, 2003). Alarm cues are released following mechanical damage to the skin (as would occur during a predation event) and when detected by nearby conspecifics and sympatric heterospecifics, can elecit dramatic short-term increases in antipredator behaviour (Chivers & Smith, 1998;Smith, 1999).…”

“…Juvenile largemouth bass Micropterus salmoides (Lace´pe`de) undergo a shift from an antipredator to a foraging response when exposed to chemical alarm cues from a heterospecific prey guild member (finescale dace Phoxinus neogaeus Cope) at c. 55 mm standard length (L S ) (Brown et al, 2001a). Green sunfish Lepomis cyanellus Rafinesque undergo a similar shift in the use of heterospecific alarm cues at c. 90 mm L S , but do not shift in response to conspecific alarm cues (Golub & Brown, 2003). These shift points, however, appear to be phenotypically plastic and subject to threat-sensitive trade-offs between foraging and predator avoidance benefits (Brown et al, 2002;Golub & Brown, 2003;Marcus & Brown, 2003).…”

“…In the absence of secondary visual information, individuals may perceive a higher risk upon detecting a chemical alarm cue, increasing potential antipredator benefits (Brown & Magnavacca, 2003;Brown et al, 2004). Thus, under conditions of high habitat complexity, an individual would be predicted to exhibit an antipredator response, while under lower habitat complexity, the same individual would be predicted to exhibit a foraging response to the same chemical information (Smith 1999;Brown et al, 2001a;Golub & Brown, 2003).…”

“…Previous studies examining the ontogenetic shift in use of chemical alarm cues by juvenile and subadult centrarchids have been conducted primarily under laboratory conditions (Brown et al, 2001a(Brown et al, , 2002Golub & Brown, 2003). This study examines the effects of habitat on the juvenile to subadult behavioural shift to conspecific and heterospecific alarm cues.…”