Unsuccessful Predation and Evolution

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Abstract
The nature and effectiveness of antipredatory defenses can be evaluated by measuring the efficiency with which predators detect, pursue and subdue prey. The most effective defense of the prey is that used during the phase of predation in which efficiency of the predator is lowest. For prey which are drilled by gastropods, for example, the hypothesis that escape is the primary defense is supported by data on predatory efficiencies during the pursuit and subjugation phases. The incidence of sublethal damage is a conservative estimate of the potential for selection in favor of resistance to subjugation. The literature on sublethal injury in mollusks and butterflies supports the idea that armored species and morphs sustain higher levels of sublethal injury than do their less well-defended counterparts. Comparisons of frequencies of sublethal damage further reveal geographical, ecological and temporal patterns in the importance of subjugation as a component of selection. These patterns include increases in antipredatory selection from high to low latitudes and altitudes, from fresh to salt water and from Paleozoic to Recent time, and accord with previous evidence and predictions. Predation is an important cause of evolutionary change. Coevolution between predator and prey may often be indirect, because an increase in predatory efficiency often accompanies enhanced antipredatory defense by the predator and is not brought about by evolution in the prey. The hypothesis that prey have an evolutionary advantage over predators in an "arms race" may be true only in situations where the 2 parties can potentially kill each other.