Predator odor

Area repellents are materials that are intended to keep animals away from a broad area. They include predator scent such as Hon or tiger manure, blood meal, tankage such as putrefied slaughterhouse waste, bone tar oil, rags soaked in kerosene or creosote, and human hair (84). Although few controlled tests have been mn on these materials in the past, more recent investigations of predator odors have shown promise (85). 

Apfelbach, R., Blanchard, C.D., Blanchard, R.J., Hayes, R.A. and McGregor, I.S. (2005) The effects of predator odors in mammalian prey species a review of field and laboratory studies. Neurosci. Biobehav. Rev. 29, 1123-1144. 

Takahashi, L. K., Nakashima, B. R., Hong, H. and Watanabe, K. (2005) The smell of danger a behavioral and neural analysis of predator odor-induced fear. Neurosci. Biobehav. Rev. 29, 1157-1167. 

Bramley, G. N. and Waas, J. R. (2001) Laboratory and field evaluation of predator odors as repellents for kiore (Rattus exidans) and ship rats (Rattus rattus). J. Chem. Ecol. 27, 1029-1047. 

Miiller-Schwarze, D. (1972) The responses of young black-tailed deer to predator odors. J. Mammal. 53, 393-394. 

Sullivan, T. P., Nordstrom, L. O. and Sullivan, D. S. (1985) Use of predator odors as repellents to reduce feeding damage by herbivores. I. Snowshoe hares (Lepus americanus). J. Chem. Ecol. 11,903-919. 

Albone [88] has reviewed the literature on anal sac secretions up to the early 1980s. Organosulfur compounds are particularly plentiful in many of these secretions and are responsible for their offensive odors. In general, predator odors seem to be repulsive to potential prey. Epple et al. [89] have speculated that the reason for the repellent properties of the feces and urine of carnivores could be diet related. It would be logical to argue that organosulfur compounds derived from a protein-rich diet could be a cue by which prey can distinguish a potential predator. The results so far are consistent with this hypothesis [90]. 

An example for stimulus generalization are responses of rats to stress-inducing odors. Laboratoiy rats of the Wistar strain respond to predator odors, specifically mercapto compounds in fox droppings, with stress reactions, for example avoidance behavior such as freezing and increased plasma corticosterone concentrations (Vemet-Mauiy et ah, 1984). The rats were trained to avoid water scented with a mercapto odorant that contained both a keto- and a sulfhydryl group (4-mercapto-4-methyl-2-pentanone). As the animals licked a waterspout, a mild electric shock was applied to their tongue. When different compounds were tested thereafter, the rats avoided compounds with similar... 

Potential prey species can chemically assess predation risk from a distance and/or from the safety of their refuge by evaluating predator odors in the area (Kats and Dill, 1998). Such odors emanate from the predator itself or its... 

Other fish species do not respond to predator odors. The threadfin shad, Doro-soma petenense, is strongly attracted to odors of its prey such as brine shrimp [Artemia) or Daphnia spp. but does not respond to those of its predator, the large-mouth bass, M. salmonides, or conspecifics. Both shad and bass swim faster than chemicals travel in water, which may explain this behavior difference (McMahon and Tash, 1979). 

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). 

In a number of species, the active predator odors originate on the dorsal skin. Neonate pygmy rattlesnakes, Sistrurus miliarius, and timber rattlesnakes, C. horridus, respond to dorsal skin chemicals of the ophiophagous king snakes and indigo snakes, Drymarchon corais, but not to those from ventral skin or skin... 

In Australia, house mice living on islands without predators did not avoid traps treated with predator odors. In areas where the introduced red fox or house cat occur, or the native western quoll, Dasyurusgeoffroyii, the mice avoided... 

In black-tailed deer, Odocoikus hemionus columbianus, fecal odors of sympatric predators (coyote, C. latrans, and mountain lion, Fdis concolor) in vials next to food pellets inhibited feeding, while those of allopatric predators (lion, Fdis leo, snow leopard, Uncia uncia) do not, or very little (Miiller-Schwarze, 1972 Fig. 12.3). Note that mammals discriminate between the odors of sym- and allopatric predators, while fish and rattlesnakes do not (pp. 359 and 364). Free-ranging adult female wapiti, Cervus elaphus canadensis, respond to the odors of dog urine, and cougar and wolf feces (presented as water slurry) with increased heart rates. It was concluded that the main effect of predator odors may be for assessing the risk of predation (Chabot etal, 1996). 

FIGURE 12.3 Responses of black-tailed deer fawns to predator odors. 

Responses to predator odors raise several questions ... 

Control of rodent and other herbivore damage Area repellents Predator odors... 

A predator odor affected a pocket gopher, Thomomys talpoides, population in western Canada. First live-trapping removed the gophers from plots of 4ha area in an orchard. Then synthetic sulfur compounds from stoat, Mustek erminea anal glands (1 1 mixture of 2-propylthietane and 3-propyl-l,2-dithiolane) were... 

Predator odors are also effective area repellents for lagomorphs. A rabbit warren sprayed with an extract from lion feces had as many as 80% fewer animals than before the treatment and also fewer than a control warren. Adult rabbits stayed away from the treated warren longer than young ones. The effect lasted up to 5 months (Boag, 1991 Boag and Mlotkiewicz, 1994). 

Predator odors do not necessarily keep herbivores away from forage. Sheep and cattle, presented with odors from coyote, fox (V. vulpes), cougar Felis concolor), or bear Ursus americanus) near their feed rations spent less time feeding there, but they did not stay away from the treated feed (Pfister eta/., 1990b). 

Laboratory and domestic animals may be poor models for avoidance of predator odors. For example, in one experiment, chickpeas were painted with the sulfur compounds w-propyldithiolane and w-propylthiolane from stoat anal gland secretion and 2,4,5-trimethylthiazoline (Fig. 3.1, p. 37) from fox feces. The chickpeas were planted and wild mice and house mice were tested to see if they would dig up and eat the peas. Wild mice remembered the predator odors better after odor exposure for 1 or 4 weeks and, consequently, may be better than laboratory mice at risk assessment (Coulston etal, 1993). 

Burwash, M. D., Tobin, M. E., Woolhouse, A. D., and Sullivan, T. P. (1998). Field testing synthetic predator odors for roof rats (Rattus rattus) in Hawaiin macadamia nut orchards. Journal of Chemical Ecology 24,603-630. 

Chabot, D., Gagnon, P., and Dixon, E. A. (1996). Effect of predator odors on heart rate and metabolic rate of wapiti [Cervus elaphus canadensis). Journal ofChemicalEcology 22,839. 

Coulston, S., Stoddart, D. M., and Crump, D. R. (1993). Use of predator odors to protect chick-peas from predation by laboratory and wild mice. Journal of Chemical Ecology 19, 607-612. 

Epple, G., Mason, J. R., Nolte, D. L., and Campbell, D. L. (1993). Effects of predator odors on feeding in the mountain beaver (Aplodontia rufa). Journal of Mammology 74, 715-711. 

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