Evolution of Antipredator Defenses in an Island Lizard, Podarcis erhardii

Antipredator Behavior;Islands;Evolution;Flight Initiation Distance;Natural Resources and Environment

Brock, KinseyBednekoff, Peter ;

University of Michigan

关键词: Antipredator Behavior;    Islands;    Evolution;    Flight Initiation Distance;    Natural Resources and Environment;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/101903/KinseyBrock_MSThesis_2013.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Over evolutionary time, many organisms have developed an array of antipredatordefenses to avoid and escape predation. Evolutionary theory predicts that ;;costly’ antipredatorbehaviors are to be selected against in the event a prey becomes isolated from predators.Predator naïveté, the ignorance of prey to threats imposed by predator species, is aphenomenon often observed on islands where limited space and resources lead to theextinction of predator species. Here, we took advantage of a Pleistocene land-bridge islandsystem with varying degrees of predator diversity and period of isolation to explore themaintenance of antipredator behaviors in a widely distributed prey species.We report on theevolution of antipredator defenses of a model island prey species (Podarcis erhardii; Squamata,Lacertidae,), and identify the factors responsible for the expression or loss of antipredatordefenses in island populations.We focus on two antipredator behaviors (flight initiation distanceand caudal autotomy), which were quantified for 37 different islands and one mainland locationthat vary in predator diversity, isolation period, and area. The results suggest that as predatordiversity is lost, both flight initiation distance and laboratory caudal autotomy defenses decreasesteadily with loss of predators. Contrary to previous studies of herpetofaunal autotomy in thissystem, we found that field autotomy rates were significantly higher on predator-free islands,and laboratory-induced autotomy was not explained solely by the presence of vipers as reportedin an earlier study. While we found that behaviors could erode relatively quickly after isolationfrom some predators (4 years), in general, behaviors eroded progressively with a duration ofisolation with the longest isolated populations having the least expressed antipredator behaviors.