Minnow predator recognition

In minnows, taste is not sufficient for predator recognition. Anosmic fathead minnows, P. pmmelas, did not show the flight reaction to the odor of northern pike, Esox lucius (Chivers and Smith, 1993). Naive European minnows, Phoxinus phoxinus, do not exhibit a fright reaction when first exposed to a predator odor, such as that of pike, E. lucius. They develop a conditioned fright response only after experiencing the predator odor in dangerous circumstances, such as when accompanied by schreckstoff (alarm pheromone) of conspecifics. Responses to the odor of non-piscivorous fishes such as tilapia, Tilapia mariae, can also be conditioned in this fashion but the responses are much weaker (Magurran, 1989). 

Chivers, D. P. and Smith, R. J. F. (1993). The role of olfaction in chemosensoiy-based predator recognition in the fathead minnow, Pimephales promelas. Journal of Chemical Ecology 19,623-633. 

The role of experience and chemical alarm signaling in predator recognition by fathead minnows, Pimephales promelas. Journal of Fish Biology 44,273-285. 

Gazdewich, K. J. and Chivers, D. P. (2002). Acquired predator recognition by fathead minnows influence of habitat characteristics on survival. Journal of Chemical Ecology 28,439-445. 

Brown, G.E. Smith, R.J.F. 1996. Foraging trade-offs in fathead minnows (Pimephales promelas) acquired predator recognition in the absence of an alarm response. Ethology, 102, 776—785. 

Chivers, D.P. Smith, R.J.F. 1994. Fathead minnows Pimephales promelas) acquire predator recognition when alarm substance is associated with the sight of unfamiliar fish. Anim. Behav., 48, 597—605. 

Acquired recognition of predator odour in the European minnow (Phoxinus phox-inus). Ethology 82,216-223. 

Recent evidence has shown that individuals are able to detect chemical alarm cues well below the overt behavioural response threshold. Fathead minnows were able to acquire the recognition of the chemical cues of a novel predator (yellow perch, Perea flavenscens) if the predator odour was paired with H3NO at concentrations as low as 0.1 nM (25% of the previously demonstrated minimum overt response threshold) (Brown et al., 2001c). Mirza and Chivers (2003) likewise found that juvenile rainbow trout did not exhibit any overt antipredator response (i.e. not different from a distilled water control)... 

In this paper we review learned recognition of heterospecific alarm cues by prey fishes. We do this by providing a case study of the fathead minnow (Pimephales promelas)/bTOok stickleback Culaea inconstans) alarm systems. Fathead minnows and brook stickleback commonly occur together in a diversity of water bodies. They share a similar suite of predators and consequently cross-species responses to alarm cues should be highly advantageous. 

Chivers et al. (2002) tested whether or not learned responses could result in a survival benefit, besides confirming that fish could learn unknown heterospecific cues through the diet or a predator. In a two-part study, fathead minnows were exposed to chemical stimuli collected from rainbow trout (Oncorhynchus mykiss) fed a mixed diet of either minnows and brook stickleback, or swordtail and stickleback. To test if the minnows had acquired recognition of stickleback alarm cues, Chivers et al. (2003) exposed the fish to stickleback alarm cues and introduced an unknown predator, yellow perch or northern pike. Both perch and pike took longer to initiate an attack on minnows that were previously exposed to trout fed minnows and stickleback than those previously exposed to trout fed swordtails and stickleback. These results show again that fishes are able to learn novel cues through association with known cues in a predator s diet. Furthermore, it shows that anti-predator responses to these newly learned cues could result in a survival benefit. 

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