Sexual dimorphism dominates divergent host plant use in stick insect trophic morphology

Roy, Denis; Seehausen, Ole; Nosil, Patrik (2013). Sexual dimorphism dominates divergent host plant use in stick insect trophic morphology. BMC evolutionary biology, 13(1), p. 135. BioMed Central 10.1186/1471-2148-13-135

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Background: Clear examples of ecological speciation exist, often involving divergence in trophic morphology. However, substantial variation also exists in how far the ecological speciation process proceeds, potentially linked to the number of ecological axes, traits, or genes subject to divergent selection. In addition, recent studies highlight how differentiation might occur between the sexes, rather than between populations. We examine variation in trophic morphology in two host-plant ecotypes of walking-stick insects (Timema cristinae), known to have diverged in morphological traits related to crypsis and predator avoidance, and to have reached an intermediate point in the ecological speciation process. Here we test how host plant use, sex, and rearing environment affect variation in trophic morphology in this species using traditional multivariate, novel kernel density based and Bayesian morphometric analyses. Results: Contrary to expectations, we find limited host-associated divergence in mandible shape. Instead, the main predictor of shape variation is sex, with secondary roles of population of origin and rearing environment. Conclusion: Our results show that trophic morphology does not strongly contribute to host-adapted ecotype divergence in T. cristinae and that traits can respond to complex selection regimes by diverging along different intraspecific lines, thereby impeding progress toward speciation.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Biology > Institute of Ecology and Evolution (IEE) > Aquatic Ecology

UniBE Contributor:

Seehausen, Ole

Subjects:

500 Science > 570 Life sciences; biology

ISSN:

1471-2148

Publisher:

BioMed Central

Language:

English

Submitter:

Marcel Häsler

Date Deposited:

29 Apr 2014 11:34

Last Modified:

02 Jan 2015 08:47

Publisher DOI:

10.1186/1471-2148-13-135

BORIS DOI:

10.7892/boris.45003

URI:

https://boris.unibe.ch/id/eprint/45003

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