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Reproductive Biology of Insular Reptiles: Marine Subsidies Modulate Expression of the "Island Syndrome"

Pafilis, Panayiotis; Foufopoulos, Johannes; Sagonas, Kostas; Runemark, Anna LU ; Svensson, Erik LU and Valakos, Efstratios D. (2011) In Copeia p.545-552
Abstract
Differences in ecological conditions can result in the evolution of dramatic inter-population shifts in whole suites of traits. We studied variation in reproductive output in three lizard populations of the Skyros Wall Lizard (Podarcis gaigeae, Lacertidae) endemic to the Skyros Archipelago (Greece), which live under similar climatic conditions but differ in predation pressure and food availability. Based on the "Island syndrome" hypothesis, we predicted that females from Island populations would produce larger, but fewer offspring. The study populations differ conspicuously in average body size, with males from the satellite Lakonissi and Diavates islets being respectively 20% and 39% larger than males from the main Skyros Island. Lizards... (More)
Differences in ecological conditions can result in the evolution of dramatic inter-population shifts in whole suites of traits. We studied variation in reproductive output in three lizard populations of the Skyros Wall Lizard (Podarcis gaigeae, Lacertidae) endemic to the Skyros Archipelago (Greece), which live under similar climatic conditions but differ in predation pressure and food availability. Based on the "Island syndrome" hypothesis, we predicted that females from Island populations would produce larger, but fewer offspring. The study populations differ conspicuously in average body size, with males from the satellite Lakonissi and Diavates islets being respectively 20% and 39% larger than males from the main Skyros Island. Lizards from these predator-free islets produced eggs of larger size than the main Skyros population; however, they also produced significantly larger clutches than the Skyros population (2.31 +/- 0.83 and 2.73 +/- 1.0 vs. 1.97 +/- 0.58 eggs). All inter-population differences in clutch size, clutch volume, and egg size were explained by corresponding differences in average body size of the dams, revealing that across all populations, reproductive effort scaled similarly with maternal body size. There was no evidence of trade-offs between egg size and clutch size as generally encountered in many reptile taxa. The occurrence of this unusual pattern of reproductive investment among islet populations of giants is probably best explained by the occurrence of two underlying drivers: first, the substantial marine subsidies by resident seabird colonies and second, the existence of intense cannibalistic behaviors in the form of attacks to the tail and severe intraspecific predation on juveniles. This suggests that subsidies-driven gigantism in island endemics may free species from such trade-offs and allow a population to maximize reproductive output in multiple, normally conflicting dimensions. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Copeia
issue
4
pages
545 - 552
publisher
American Society of Ichthyologists and Herpetologists
external identifiers
  • wos:000298829600009
  • scopus:84855383564
ISSN
0045-8511
DOI
10.1643/CE-10-041
language
English
LU publication?
yes
id
b70fb0d3-b45a-40e6-957a-784ff8e6d852 (old id 2348302)
date added to LUP
2012-02-24 12:43:49
date last changed
2017-10-01 04:21:35
@article{b70fb0d3-b45a-40e6-957a-784ff8e6d852,
  abstract     = {Differences in ecological conditions can result in the evolution of dramatic inter-population shifts in whole suites of traits. We studied variation in reproductive output in three lizard populations of the Skyros Wall Lizard (Podarcis gaigeae, Lacertidae) endemic to the Skyros Archipelago (Greece), which live under similar climatic conditions but differ in predation pressure and food availability. Based on the "Island syndrome" hypothesis, we predicted that females from Island populations would produce larger, but fewer offspring. The study populations differ conspicuously in average body size, with males from the satellite Lakonissi and Diavates islets being respectively 20% and 39% larger than males from the main Skyros Island. Lizards from these predator-free islets produced eggs of larger size than the main Skyros population; however, they also produced significantly larger clutches than the Skyros population (2.31 +/- 0.83 and 2.73 +/- 1.0 vs. 1.97 +/- 0.58 eggs). All inter-population differences in clutch size, clutch volume, and egg size were explained by corresponding differences in average body size of the dams, revealing that across all populations, reproductive effort scaled similarly with maternal body size. There was no evidence of trade-offs between egg size and clutch size as generally encountered in many reptile taxa. The occurrence of this unusual pattern of reproductive investment among islet populations of giants is probably best explained by the occurrence of two underlying drivers: first, the substantial marine subsidies by resident seabird colonies and second, the existence of intense cannibalistic behaviors in the form of attacks to the tail and severe intraspecific predation on juveniles. This suggests that subsidies-driven gigantism in island endemics may free species from such trade-offs and allow a population to maximize reproductive output in multiple, normally conflicting dimensions.},
  author       = {Pafilis, Panayiotis and Foufopoulos, Johannes and Sagonas, Kostas and Runemark, Anna and Svensson, Erik and Valakos, Efstratios D.},
  issn         = {0045-8511},
  language     = {eng},
  number       = {4},
  pages        = {545--552},
  publisher    = {American Society of Ichthyologists and Herpetologists},
  series       = {Copeia},
  title        = {Reproductive Biology of Insular Reptiles: Marine Subsidies Modulate Expression of the "Island Syndrome"},
  url          = {http://dx.doi.org/10.1643/CE-10-041},
  year         = {2011},
}