Predator chemicals, responses

Experimental data suggest that VN stimuli might also play a relevant role in prey-predator interactions by mediating affective responses to prey or predator chemical cues. For instance, one of the preferred prey for the snake Thamnophis sirtalis is earthworms. Halpern (1988) demonstrated that earthworm wash constitutes a VN stimulus that is rewarding for these snakes. On the other hand, it has been shown that rats display defensive reactions to a collar that has been worn by a cat, even if they have no previous experience with cats. For these defensive behavioral responses to occur, direct contact with the collar is needed (Dielenberg and McGregor 2001). 

A particularly large and varied class of eavesdroppers includes prey species that learn of impending danger from chemical signals disseminated by their predators. Prey responses to these warning... 

Numerous studies have shown that neonate or naive reptiles can already show complete species-specific chemical responses to conspecifics or rely on some form of social imprinted responses to food organism or predators, developed by interactions of genetic factors and experience, with each contributing. 

Table 12.5 Responses of amphibian prey to predator chemicals...

Table 12.7 Examples of responses of mammals of predator chemicals...

FIGURE 12.2 Responses of beavers to predator chemicals applied to aspen sticks. Activity periods were consecutive 5 days of experiment in two areas in New York and the percentages of sticks consumed is the mean of several replications of the experiment. All treated sticks were punctured to improve the uptake of chemicals intact sticks were untreated (A), punctured but not treated ( ), punctured and treated with the solvent methanol ( ) (the three controls), or treated with extracts from other animals. Treatments that inhibited consumption most were excrement extracts from lynx (+) and coyote ( ... ), both sympatric predators (lynx now extirpated). Beavers accepted most readily the three control sets. Other chemicals were from otter (o), wolf ( - ), lion ( ). (From Engelhart and Miiller-Schwarze,... 

Engelhart, A. and MUller-Schwarze, D. (1995). Responses of beavers Castor canadensis Kuhl) to predator chemicals. Journal of ChemicalEcology 21,1349-1364. 

Laurila, A. (2000). Responses to predator chemical cues and local variation in antipredator behaviour of Rana temporaria tadpoles. Oikos 88,159-168. 

Engelhart A, Miiller-Schwarze D (1995) Responses of beaver Castor canadensis) to predator chemicals. J Chem Ecol 21 1349-1364... 

Interspecific Stimuli Kairomones Prey Responses to Predator Chemicals... 

Stoddart, D. M., 1980, Some responses of a free-living community of rodents to the odors of predators, "Chemical Signals in Vertebrates, ... 

The use of chemical cues in predator/prey interaction appears widespread among amphibians (Kats Dill 1998). Chemical alarm pheromones have been examined most extensively in larval frogs and toads (Chivers Smith 1998). However, recent experiments also suggest that caudate amphibians use chemical alarm pheromones. Numerous studies have investigated the use of chemical substances that make amphibians noxious or toxic to predators. Chemical cues from predators often induce antipredator responses in amphibian prey. In some cases, chemical cues may be the primary sensory stimuli used for predator recognition. Chemosen-sory-induced antipredator responses may include behavioral defenses as well as alterations in life-history characteristics. 

To determine whether viviparous lizards (L. vivipara) show innate responses to chemical cues from predatory snakes from birth, or learn them through experience, the preceding experiments were duplicated (Van Damme et al. 1995). Seventeen juvenile common lizards (L. vivipara) were exposed to a clean cage or to a cage that had previously housed the lizard-eating adder V. berus) or smooth snake (C. austriaca). Juveniles that had never been exposed to predator chemical cues before behaved like the animals used in the previous study by Thoen et al. (1986). One difference in the behavior of juvenile and adult lizards... 

Van Damme, R., D. Bauwens, C. Thoen, D. Vanderstighelen R.F. Verheyen. 1995. Responses of naive lizards to predator chemical cues. J. Herpetol. 29 38-43. 

Interested readers can find information on geographic variation in aboveground architecture and leaf characters of Encelia farinosa in response to temperature and available water in Housman et al. (2002), and a discussion of chemical variation and defense against predation in a report by Wisdom (1985). 

A recent example demonstrates that corals rely on induced biosynthesis of terpenes as a dynamic defense strategy as well. The induction of terpenoid secondary metabolites was observed in the sea whip Pseudopterogorgia elisabethae [162]. Levels of pseudopterosins 89-92, a group of diterpene glycosides with anti-inflammatory and analgesic properties (Scheme 23) [163-165], are increased in response predation by the mollusk Cyphoma gibbosum. First bioassays indicate that these natural products are involved in the chemical defense. 

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