Predator avoidance

Although no consistently effective chemical repellent has been developed for vertebrate pests, some promising materials have been tested as repellents that are based on predator avoidance, specifically compounds from the secretions of predators. In 1995, synthetic sulfur compounds (two thietanes, a thiolane, and a substituted methyl sulfide, which were originally identified from the anal glands of the stoat, ferret, and red fox) suppressed browsing by the introduced AustraUan bmsh-tail opossum in New Zealand about as well as FEP (83). Suggestions were made that these compounds can be made more effective by the use of bitter compounds in a cocktail. 

Webber HM, Haines TA. 2003. Mercury effects on predator avoidance behavior of a forage fish, golden shiner (Notemigonus ctysoleucas). Environ Toxicol Chem 22 1556-1561. 

The eyespots on butterfly wings are a recently derived evolutionary novelty that arose in a subset of the Lepidoptera and play an important role in predator avoidance. The production of the eyespot pattern is controlled by a developmental organizer called the focus, which induces the surrounding cells to synthesize specific pigments. The evolution of the developmental mechanisms that establish focus was therefore the key to the origin of butterfly eyespots (Keys et al., 1999, p.532). 

Brown, J.A., P.H. Johansen, P.W. Colgan, and R.A. Mathers. 1985. Changes in the predator-avoidance behaviour of juvenile guppies (Poecilia reticulata) exposed to pentachlorophenol. Canad. Jour. Tool. 63 2001-2005. 

It is well known that dogs track better in humid air. Rodents find buried seeds better in wet soil. This is important in arid climates. After rains, yellow pine chipmunks, Tamias amoenus, and deer mice, Peromyscus maniculatus found experimentally buried seeds of Jeffrey pine, Pinus jeffreyi, and antelope bitterbrush, Purshia tridentata, better than in diy soil. The recovered number of seeds increased 27- and 15-fold, respectively. In wet soil, seeds take up water rapidly and emanate volatile organic compounds that the rodents exploit. By extension, variations in humidity in arid environments may have profound effects on olfaction-dependent behaviors such as finding food, social interactions, preying, and predator avoidance (Vander Wall 1998). 

Aquatic animals use their chemical senses in all aspects of their lives, from reproductive behavior to feeding, habitat selection, and predator avoidance. The hydrodynamic properties determine the possibilities and limits of chemical communication in water. As a medium, water is as dynamic as air, so that convection and advection are far more important for odor transport than is diffusion. Distribution by currents is even more important in water because compounds of similar molecular weight diffuse four orders of magnitude more slowly than in air (Gleeson, 1978). Diffusion of odorants may be important only in the submillimeter range, while turbulence is typical for water masses above the centimeter range. 

Striped bass, Morone saxatilis, juveniles develop in estuaries, notably Hudson River and Chesapeake Bay. Juveniles school during the day but disperse and feed at night. Schools provide the advantages of improved prey location, predator avoidance, and swimming hydrodynamics. How are the fish attracted to each other In Y-maze tests in the laboratory, juveniles are attracted to both... 

Predatory fish may also be affected by alarm pheromones (Section 7.2) of the prey, both directly and indirectly. The alarm odor may act as defense compoimd that inhibits predator attack or reduces capture rate by inducing predator avoidance in school members of the prey species. 

In their predator avoidance, salamanders use complex odors that combine chemicals from both predator and prey. In the laboratory, red-backed salamanders, P. cinereus, avoid filter papers soaked with water extracts from garter snakes that had been preying on salamanders, while earthworm-fed snakes lacked this effect. Exudations from unfed snakes and extracts from homogenized salamanders had no such alarming effect (Madison etal, 2002). 

Webster, D. B. (1973). Audition, vision, and olfaction in kangaroo rat predator avoidance. 

Persons, M. H., Walker, S.E., Rypstra, A.L. and Marshall, D. S. (2001). Wolf spider predator avoidance tactics and survival in the presence of diet-associated predator cues (Araneae Lycosidae). Animal Behaviour 61 43-51. 

Bollens, S.M., Frost, B.W., Thoreson, D.S., and Watts, S.J., Diel vertical migration in zooplankton field evidence in support of the predator avoidance hypothesis, Hydrobiologia, 234, 33, 1992. 

Dobson, S.I., The ecological role of chemical stimuli for the zooplankton predator avoidance behavior in Daphnia, Limnol. Oceanogr., 33, 1431, 1988. 

Fish use amino acids in the water for both feeding and predator avoidance. Acidification of their water can change their feeding behavior. For example, Atlantic salmon, Salmo salar, normally are attracted to glycine, but avoid L-alanine. If the pH of their water is lowered from 7.6 to 5.1, the fish become indifferent to glycine, but are now attracted to alanine (Royce-Mahngren and Watson 1987). Attempt some version of an experiment with fish responses to amino acids at different pH levels. 

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. 

Olfaction, the sense of smell, is an important neural system in various animal species, including fish, for their life. Fish can detect a variety of odorants emitted from objects and dissolved in the water, such as amino acids, bile salts, nucleotides, polyamines, prostaglandins, and steroids. The fish olfactory system is extensively developed to receive and discriminate these odorant molecules, to transmit their signals to the brain, and to mediate fundamental behaviors such as food finding, alarm response, predator avoidance, social communication, reproductive activity, and spawning migration (Sorensen and Caprio 1998 Zielinski and Hara 2007). 

UV photoreceptors have also been identified in several zooplankton prey, such as the cladoceran Daphnia magna [75]. It is possible that these UV photoreceptors may also serve a means of predator avoidance. However, this hypothesis has yet to be fully tested. 

Many species of larval fish have retinal cones that perceive UV-A (350-370 nm) and these are thought to help larvae locate and capture their prey [63,64]. However, some prey species also have UV-A photoreceptors. Responses to UV-A wavelengths in these organisms may therefore also be a means of predator avoidance in the surface waters. In this case, predation may be the ultimate cause of DVM but UV-A light would be the proximate cue. Further investigation is needed to test these types of hypotheses. 

Most of what is known about crustacean chemoreception is in the context of food detection and ingestion only very little is known in other behavioral contexts, such as predator avoidance, orientation in the habitat, interactions with symbiotic partners, or intraspecific communication by pheromones. From recent behavioral and neuroanatomical studies, two important concepts about pheromone reception in crustaceans have emerged ... 

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