Predator learning

Predators learn to avoid distasteful salamanders. When molested, spotted salamanders Ambystoma maculatum) discharge a white slime, mostly in the tail region. They also raise and wag their tail when a predator is near. In one experiment, four out of five chickens learned to avoid these salamanders by sight after... 

The red eft stage of the red-spotted newt contains toxic, bad-tasting chemicals in its skin. As a result, many potential predators learn to avoid this animal, and will not eat red efts. The range of the red salamander Pseudotriton ruber) overlaps part of the larger range of the red-spotted newt in the eastern United States. It appears that the superficially similar but non-toxic red salamander may be a mimic of the color of the red eft, taking advantage of the fact that many predators avoid this animal as food. 

Many workers have explored various aspects of predator learning when presented with mimetic complexes (see Section 10.4.4 for list of experiments and references). Many facets of Batesian mimicry such as degree of resemblance, degree of punishment and frequency of mimics have been investigated successfully by these methods. 

Rothschild (1979) has made a strong case that various pre-adaptations play a very important, even vital, role in the evolution of Batesian mimics. These traits, such as rarity, would not predispose a species to mimicry but, if present, facilitate or allow such evolution toward Batesian mimicry. Thus rarity would not arise after the occiurence of Batesian mimicry, but would be almost a precondition as a result of predator learning. If this suggestion is correct, it would place severe limits on the evolution of Miillerian mimics into Batesian mimics as discussed above. 

Abstract For most mammals, the ability to detect odours and discriminate between them is necessary for survival. Information regarding the availability of food, the presence of predators and the sex, age and dominance status of conspecifics is odour mediated. Probably because of this extraordinary reliance upon odour cues, mice and rats have developed the ability to learn and remember information associated with olfactory cues as effectively as primates recall visually related cues. As a result, these rodents have become the model of choice to study the neural and cognitive processes involved in olfactory discrimination. In this paper, we describe some of the more ethologically based tasks used in assessing olfactory discrimination and the advantages and disadvantages of the different methodologies employed. 

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... 

Learn to distinguish pests from their predators. 

Other physiological effects of defensive chemicals have not been observed or studied for plant-herbivore interactions. For example, studies of chemically defended sessile invertebrates have shown that some compounds have emetic properties against fish predators, and that fishes can learn quickly to avoid these chemicals after regurgitating ingested food.206,258 Macroalgal compounds could potentially act in similar ways, but such effects have never been documented. 

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