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Comparison of life-history characteristics of island and mainland populations of the swamp antechinus

journal contribution
posted on 2009-02-01, 00:00 authored by M Sale, Barbara Wilson, John ArnouldJohn Arnould
The reproductive ecology of the swamp antechinus Antechinus minimus, a small dasyurid (Dasyuridae) marsupial with obligate male semelparity, was investigated in populations inhabiting the mainland coast and on a nearby offshore island in south-eastern Australia. The size and sex ratios of litters, individual body mass and size, timing of births and female longevity were determined from live-trapped animals. The island population had significantly smaller litter sizes and greater adult body mass in comparison with the mainland population. This is consistent with features of the ‘island syndrome’, which predicts directional selection for these traits in high-density populations with reduced extrinsic mortality. However, inter-annual variability in litter sizes in the island population suggests that litter size is more responsive to fluctuating local conditions, such as population density, which is likely to affect food availability, rather than directional genetic changes. In contrast with other antechinus species, biased sex ratios were not evident. In addition, large variations of the timing of births were estimated at both sites and these appear to be related to seasonal conditions such as autumn rainfall and female body mass before mating.

History

Journal

Journal of zoology

Volume

277

Issue

2

Pagination

119 - 125

Publisher

Wiley-Blackwell Publishing Ltd.

Location

Oxford, England

ISSN

0952-8369

eISSN

1469-7998

Language

eng

Publication classification

C1 Refereed article in a scholarly journal

Copyright notice

2008, Wiley-Blackwell Publishing