Fright reaction

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). 

Many decades ago, Griffith (1919,1920) described the white (laboratory) rat s response to cats. From the age of 3 weeks, rats huddle in corners, freeze, and crouch when presented with a cat. They tremble, twitch their muscles, whine, and cease to feed and nurse. A cloth with cat scent or an arena with cat scent sufficed to trigger these responses. Anosmic rats or those confronted with a cat in a glass jar remained unaffected. Hence, the critical cue proved to be odor (Griffith, 1919). Cat feces, urine, heart, or other tissues did not elicit these fright reactions (Griffith, 1920). 

Pfeiffer, W. (1978). Heterocyclic compounds as releasers of the fright reaction in the giant dznioDaniomalabaricus ]erdon)[Cypnnidze, Ostzriophysi,Tisces).Journal of Chemical Ecology 4, 665-673. 

Reed, J. P. (1969). Alarm substances and fright reaction in some fishes from the Southeastern United States. Transactions of the American Eisheries Society 98,664-668. 

The cabbage worm butterfly Pieris rapae crucivora and the sulfur-colored Catopsilia crocale are both found to afford the anticancer component isoxanthopterin (67) (57). In addition, isoxanthopterin (67) from the skin of the European minnow, Phoxinus phoxinus, elicits the fright reaction and hence acts as the alarm substance (52). 

Pfeiffer, W., The distribution of fright reaction and alarm substance cells in fishes, Copeia, 1977, 653. 

Concerning rog larvae, Pfeiffer (1963, 1966) tested alarm responses in tadpoles of Rana esculenta, R. temporaria, R. pipiens, Hyla arborea, and Xenopus laevis to skin extracts of conspecifics, and concluded that fright reactions were not present in these species. Skin extract of R. temporaria was also negative in tests with toad Bufo bufo) tadpoles, and R. temporaria tadpoles did not respond to skin extract of toad tadpoles. These results made him suggest that non-bufonids lack both the alarm substance and the ability to respond to the alarm substance. 

The effectiveness of the overt fright reaction as defense has been demonstrated in fathead minnows Pimephales promelas) where the overt responses decrease an individual s vulnerability to predation by pike in laboratory tanks (Mathis Smith 1993b). There is also evidence that the overt responses are often contingent on other variables. For example, both Iowa darters (Etheostoma exile) (Smith 1981), which are not ostariophysans, and fathead minnows, which are, (Brown Smith 1996) show a reduction or absence of overt responses when foraging tradeoffs are increased by 48 hours of food deprivation. Common shiners Luxilus cornutus) vary their responses to alarm pheromones according to whether they detect an aquatic or avian predator in the vicinity (Heczko 1980). 

Irving, P.W. Magurran, A.E. 1997 Context-dependent fright reactions in captive European minnows the importance of naturalness in laboratory experiments Animal Behaviour, 53,193—1201. 

Smith, R.J.F. 1976b. Male fathead minnows Pimephales promelas Rafinesque) retain their fright reaction to alarm substance during the breeding season. Can. J. Zool., 54,2230-2231. 

Smith, R.J.F. 1982. The adaptive significance of the alarm substance— fright reaction system In Chemoreception in Fishes. (Ed. by T.J. Kara), pp. 327—342. Amsterdam Elsevier. 

Both Reed et al. (1972) and Ruddy and Baeder (1973) elicited fright reactions with histamine but histamine is present in all vertebrates while the alarm pheromone is specific to ostariophysans. Histamine "Occurs widely in nature as a result of putrefactive processes" (Stecher et al., p. 533, 1969). So the response reported by Reed et al. (1972) and Ruddy and Baeder (1973) may be an adaptive avoidance response to odours of putrefaction rather than a specific response to conspecific alarm pheromone. Neither group of researchers tested the response of non-ostariophysan fish to histamine. 

There is no direct experimental evidence to show that the fright reaction actually improves the survival of the receiver. There are, however, a number of correlations between the fright reactions shown by various fish when they detect alarm substance and their reactions to other indicators of predation. The most general type of reaction in schooling fish is for the school to aggregate and move away from the area of the stimulus. This type of response was first recorded in the European minnow by von Frisch (1938) and has since been observed in many species (Pfeiffer, 1977). 

Other types of fright reaction occur among fishes (Pfeiffer, 1963b). 

Some bottom-dwelling species sink to the bottom and remain motionless other species that normally live near the surface flee to the water surface and may jump out of the water (Schutz, 1956). In general the fright reaction is appropriate to the biology of the species. 

Predator specific fright reactions occur in the common shiner. They respond to alarm substance by seeking cover in vegetation if a kite, simulating an piscivorous bird, is flown over their tank,but they do not enter cover if a predatory fish is present in the tank (Heczko, 1980 Heczko and Seghers, 1981). 

Ahsan, S. N.,and Prasad, M., 1982, Occurrence of fright reaction in Indian fishes, Biol. Bull. India, 4 41-47 ... 

Gandolfi, G., Mainardi, D., and Rossi, A. C., 1968, The fright reaction of zebra fish. Atti della Societa Italiana di Scienze Naturali e del Museo Civico di Storia Naturale di Milano, 107 74-88. 

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