Antipredator Mechanisms in Arthropods: A Twenty Year Literature Survey

Abstract

Sixteen ecological and entomological journals were surveyed from 1969-1989 for articles concerning defensive mechanisms in arthropods. Predators and prey are listed taxonomically by family, and grouped according to the specific defensive mechanism employed by the prey. A dichotomous categorization scheme is proposed which primarily reflects the hypothesized energetic costs of various antipredator mechanisms. In total, 354 papers were examined involving 555 potential or real predator/prey interactions. It is concluded that certain defensive mechanisms are prevalent in particular taxonomic groups as indicated by the literature. Several predator/prey pairs occur together in interactions more frequently than would be expected by chance (up to 39 times in one case). Most pairs (71 percent) occur together ten or fewer times. Thirty-four pairs (nine percent) occurred only once. It is questionable whether this phenomenon is an accurate representation of the natural distribution of defensive mechanisms in arthropods because of the potential and real bias involved in the investigative process. Many studies assume but do not demonstrate the efficacy of the alleged defensive mechanism. Of 555 real or potential interactions, a defensive function was demonstrated 354 times (64 percent). No defensive function was demonstrated 201 times (36 percent). It is suggested that whenever possible, future investigations incorporate tests of the hypothesized defensive function against sympatric, and therefore ecologically relevant predators.