TY - JOUR
T1 - Intraspecific competition, not predation, drives lizard tail loss on islands
AU - Itescu, Yuval
AU - Schwarz, Rachel
AU - Meiri, Shai
AU - Pafilis, Panayiotis
N1 - Publisher Copyright:
© 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society
PY - 2017/1/1
Y1 - 2017/1/1
N2 - Tail autotomy is mainly considered an antipredator mechanism. Theory suggests that predation pressure relaxes on islands, subsequently reducing autotomy rates. Intraspecific aggression, which may also cause tail loss, probably intensifies on islands due to the higher abundance. We studied whether tail autotomy is mostly affected by predation pressure or by intraspecific competition. We further studied whether predator abundance or predator richness is more important in this context. To test our predictions, we examined multiple populations of two gecko species: Kotschy's gecko (Mediodactylus kotschyi; mainland and 41 islands) and the Mediterranean house gecko (Hemidactylus turcicus; mainland and 17 islands), and estimated their abundance together with five indices of predation. In both species, autotomy rates are higher on islands and decline with most predation indices, in contrast with common wisdom, and increase with gecko abundance. In M. kotschyi, tail-loss rates are higher on predator and viper-free islands, but increase with viper abundance. We suggest that autotomy is not simply, or maybe even mainly, an antipredatory mechanism. Rather, such defence mechanisms are a response to complex direct and indirect biotic interactions and perhaps, in the case of tail autotomy in insular populations, chiefly to intraspecific aggression.
AB - Tail autotomy is mainly considered an antipredator mechanism. Theory suggests that predation pressure relaxes on islands, subsequently reducing autotomy rates. Intraspecific aggression, which may also cause tail loss, probably intensifies on islands due to the higher abundance. We studied whether tail autotomy is mostly affected by predation pressure or by intraspecific competition. We further studied whether predator abundance or predator richness is more important in this context. To test our predictions, we examined multiple populations of two gecko species: Kotschy's gecko (Mediodactylus kotschyi; mainland and 41 islands) and the Mediterranean house gecko (Hemidactylus turcicus; mainland and 17 islands), and estimated their abundance together with five indices of predation. In both species, autotomy rates are higher on islands and decline with most predation indices, in contrast with common wisdom, and increase with gecko abundance. In M. kotschyi, tail-loss rates are higher on predator and viper-free islands, but increase with viper abundance. We suggest that autotomy is not simply, or maybe even mainly, an antipredatory mechanism. Rather, such defence mechanisms are a response to complex direct and indirect biotic interactions and perhaps, in the case of tail autotomy in insular populations, chiefly to intraspecific aggression.
KW - autotomy
KW - defence mechanisms
KW - geckos
KW - intraspecific aggression
KW - islands
KW - lizards
KW - population abundance
KW - predation pressure
UR - http://www.scopus.com/inward/record.url?scp=84990946189&partnerID=8YFLogxK
U2 - 10.1111/1365-2656.12591
DO - 10.1111/1365-2656.12591
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AN - SCOPUS:84990946189
SN - 0021-8790
VL - 86
SP - 66
EP - 74
JO - Journal of Animal Ecology
JF - Journal of Animal Ecology
IS - 1
ER -