Density, body size and sex ratio of an indigenous spider along an altitudinal gradient in the sub-Antarctic

dc.contributor.authorLee, Jennifer E.
dc.contributor.authorSomers, Michael J.
dc.contributor.authorChown, Steven Loudon
dc.date.accessioned2012-03-15T06:30:48Z
dc.date.available2013-01-31T10:07:44Z
dc.date.issued2012
dc.description.abstractAlthough spiders are a diverse and ecologically important group of predators across the sub-Antarctic islands, relatively little is known about their biology. Here we provide data on the abundance, body size variation and sex ratio of an indigenous spider, Myro kerguelenensis, across an altitudinal gradient on Marion Island. In so doing we test explicitly the hypotheses that density will decline with declining resource availability at higher elevations, and that a converse Bergmann body size cline will be found in this species. Density of M. kerguelenensis decreased with altitude and ranged from a mean density of 5.3 (SD 3.42) individuals per m2 at 50m a.s.l. to a mean density of 0.83 (SD 1.15) individuals per m2 at 600m a.s.l. Mean female sternum width was 1.39mm (SD 0.44) and mean male sternum width was 1.40mm (SD 0.22). No evidence for Bergmann or converse Bergmann clines was found. At increasing altitudes, sex ratios became increasingly female-biased with populations at 600m a.s.l. comprising 0.87 (SD 0.28) females, on a proportional basis, possibly as a result of resource limitation and an increase in the prevalence of sexual cannibalism. The food web implications of this study are highlighted.en
dc.description.librariannf2012en
dc.description.sponsorshipFieldwork by KQ and MJS was supported by a USAID grant to SLC and by the South African Department of Environmental Affairs and Tourism.en_US
dc.description.urihttp://journals.cambridge.org/action/displayJournal?jid=ansen_US
dc.identifier.citationLee, JE, Somers, MJ & Chown, SL 2012, 'Density, body size and sex ratio of an indigenous spider along an altitudinal gradient in the sub-Antarctic', Antarctic Science, vol. 24, no. 1, pp. 15-22.en
dc.identifier.issn0954-1020 (print)
dc.identifier.issn1365-2079 (online)
dc.identifier.other10.1017/S0954102011000629
dc.identifier.urihttp://hdl.handle.net/2263/18442
dc.language.isoenen_US
dc.publisherCambridge University Pressen_US
dc.rights© Antarctic Science Ltd 2011. This article is embargoed by the publisher until January 2013.en
dc.subjectAraneaeen
dc.subjectBergman body size clineen
dc.subjectMyro kerguelenensisen
dc.subjectResource limitationen
dc.subject.lcshSpiders -- Size -- Prince Edward Islands -- Marion Islanden
dc.subject.lcshAnimal population density -- Prince Edward Islands -- Marion Islanden
dc.subject.lcshSpiders -- Sex ratio -- Prince Edward Islands -- Marion Islanden
dc.subject.lcshSpiders -- Effect of altitude on -- Prince Edward Islands -- Marion Islanden
dc.titleDensity, body size and sex ratio of an indigenous spider along an altitudinal gradient in the sub-Antarcticen
dc.typeArticleen

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