Resource shifts in Malagasy dung beetles: contrasting processes revealed by dissimilar spatial genetic patterns.

Ilkka Hanski,Pierre Rahagalala,Toshka Nyman,Helena Wirta

doi:10.1111/j.1461-0248.2008.01239.x

Ilkka Hanski, Pierre Rahagalala + Show 2 more

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https://doi.org/10.1111/j.1461-0248.2008.01239.x

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Abstract

The endemic dung beetle subtribe Helictopleurina has 65 species mostly in wet forests in eastern Madagascar. There are no extant native ungulates in Madagascar, but three Helictopleurus species have shifted to the introduced cattle dung in open habitats in the past 1500 years. Helictopleurus neoamplicollis and Helictopleurus marsyas exhibit very limited cytochrome oxidase subunit 1 haplotype diversity and a single haplotype is present across Madagascar, suggesting that these species shifted to cattle dung in a small region followed by rapid range expansion. In contrast, patterns of molecular diversity in Helictopleurus quadripunctatus indicate a gradual diet shift across most of southern Madagascar, consistent with somewhat broader diet in this species. The three cattle dung-using Helictopleurus species have significantly greater geographical ranges than the forest-dwelling species, apparently because the shift to the currently very abundant new resource relaxed interspecific competition that hinders range expansion in the forest species.Ecology Letters (2008) 11: 1208–1215

Highlights

Shifts in resource use often punctuate both the ecological and the evolutionary dynamics of species
Resource shifts may lead to range expansion and changes in population dynamics, as exemplified by the European corn borer moth (Ostrinia nubilalis), which has two sympatric host races in Europe, one feeding on Artemisia vulgaris and the other using maize
As there are no known ecological differences between the species, and as the slight differences in morphology may be related to body size difference, it is likely that H. littoralis represents small individuals of a single taxon, which is here called H. neoamplicollis

Summary

Introduction

Shifts in resource use often punctuate both the ecological and the evolutionary dynamics of species. Resource shifts may lead to range expansion and changes in population dynamics, as exemplified by the European corn borer moth (Ostrinia nubilalis), which has two sympatric host races in Europe, one feeding on Artemisia vulgaris and the other using maize. The latter race must have evolved through host shift following the introduction of maize to Europe 500 years ago (Calcagno et al 2007). Reuse of this article is permitted in accordance with the Creative Commons Deed, Attribution 2.5, which does not permit commercial exploitation.

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