Counter-defense technique to mitigate prey toxicity in raccoons (Procyon lotor)

Abstract

Predator-prey relationship acts as a major source of natu- ral selection for both predator and prey. A prey attempts to foil predation through antipredator defenses such as wounding or poisoning a predator (Edmunds 1974). Chemical defenses using toxic substances are wide- spread among taxa (Edmunds 1974) and are the most diverse and complex secondary defenses, operating once a predator initiates an attack (Ruxton et al. 2004). In predators, specialized handling techniques or stamina are required to successfully consume chemically-protected prey (Edmunds 1974). If animals continue to be success- ful in a predator-prey relationship, improved counter- defense abilities in a predator will induce compensatory improvements of defense abilities in a prey and vice versa (Brodie and Brodie 1999a; Thompson 1994). Thus, it is expected that a predator’s counter-defense ability against a prey toxin will cause a corresponding shift in prey toxicity through reciprocal selection. It has been demonstrated in the field that a predator equipped with physiological resistance to a toxin induces a higher toxicity in the prey (Brodie and Brodie 1999b). There- fore, such predators play an important role in the evolu- tion of the diversity of prey toxicity (Edmunds 1974; Brodie et al. 2002).