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Potential ‘costs of reproduction’ in a skink: Inter- and intrapopulational variation

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Wapstra, E and O'Reilly, J (2001) Potential ‘costs of reproduction’ in a skink: Inter- and intrapopulational variation. Austral Ecology, 26. pp. 179-186. ISSN 1442-9985

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Abstract

Reproductive costs are important determinants of reproductive effort in squamate reptiles.
Consequently, differences in costs of reproduction between populations of geographically or climatically widespread
species are likely to result in different patterns of reproductive effort. In the present study, the effect of
pregnancy on sprint speed was examined in a small viviparous skink, Niveoscincus ocellatus (Gray 1845), from two
populations at the climatic extremes of its distribution. Decreased sprint speed has the potential to be an important
cost of reproduction in this species, through a reduced ability to avoid predation and/or decreased foraging
efficiency. Lizards inhabiting the colder site were larger than those from the warmer site and, contrary to predictions
from life history theory, had a higher reproductive effort. In both populations, sprint speed was lower
in pregnant lizards than in either the same individuals after birth or non-pregnant control lizards. Within each
population, sprint speed was unrelated to the level of reproductive effort of the female in terms of either absolute
mass of the reproductive burden or the burden relative to her post-partum body mass. However, within each
population, the mass of the clutch that an individual female was carrying relative to snout–vent length was
an important determinant of her sprint speed while pregnant. Thus, within each population, a relatively high reproductive
burden may potentially increase costs of reproduction in this species. Despite this relationship and predictions
from life history theory suggesting that annual reproductive effort will be lower in populations with a large
body size and delayed maturity, it is suggested that a higher reproductive effort at the cold site is possible because
they have a higher absolute sprint speed because of their larger size and a relatively higher abundance of cover at
the cold site, and differences in predation pressure may alter selective pressures on reproductive investment.

Item Type: Article
Keywords: costs of reproduction, geographical variation, life history evolution, Niveoscincus ocellatus, relative clutch mass, reproductive effort, sprint speed
Journal or Publication Title: Austral Ecology
Page Range: pp. 179-186
ISSN: 1442-9985
Identification Number - DOI: 10.1046/j.1442-9993.2001.01104.x
Additional Information:

The definitive version is available at www.blackwell-synergy.com

Date Deposited: 30 Oct 2007 00:51
Last Modified: 18 Nov 2014 03:24
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