Can tooth differentiation help to understand species coexistence? The case of wood mice in China |
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Authors: | Ronan Ledevin Jean‐Pierre Quéré Johan R Michaux Sabrina Renaud |
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Institution: | 1. Paléoenvironnement et Paléobiosphère, UMR 5125, CNRS, Université Lyon 1, Campus de la Doua, Villeurbanne, France;2. Anthropologisches Institut & Museum Universit?t Zürich‐Irchel Winterthurerstrasse 190, 8057 Zürich, Switzerland;3. Centre de Biologie et Gestion des Populations (INRA/IRD/Cirad/Montpellier SupAgro), Campus international de Baillarguet, Montferrier‐sur‐Lez Cedex, France;4. Centre de Biologie et Gestion des Populations (INRA/IRD/Cirad/Montpellier SupAgro), Campus international de Baillarguet, Montferrier‐sur‐Lez Cedex, France/Génétique des micro‐organismes, University of Liège, Institute of Botany (Bat. 22) 4000 Liège, Belgium;5. Laboratoire de Biométrie et Biologie Evolutive, UMR 5558, CNRS, Université Lyon 1, Campus de la Doua, Villeurbanne, France |
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Abstract: | Five wood mice Apodemus species occur across China, in allopatry but also in sympatry up to cases of syntopy. They all share a similar external appearance, similar habitats of grasslands and forests and a generalist feeding behaviour. This overall similarity raises questions about the mechanisms insuring competition avoidance and allowing the coexistence of the species. In this context, a morphometric analysis of two characters related to feeding (mandible and molar) addressed the following issues: (1) Were the species actually different in size and/or shape of these characters, supporting their role in resource partitioning? (2) Did this pattern of phenotypic divergence match the neutral genetic differentiation, suggesting that differentiation might have occurred in a former phase of allopatry as a result of stochastic processes? (3) Did the species provide evidence of character displacement when occurring in sympatry, supporting an ongoing role of competition in the interspecific divergence? Results evidenced first that different traits, here mandibles and molars, provided discrepant pictures of the evolution of the Apodemus group in China. Mandible shape appeared as prone to vary in response to local conditions, blurring any phylogenetic or ecological pattern, whereas molar shape evolution appeared to be primarily driven by the degree of genetic differentiation. Molar size and shape segregated the different species in the morphospace, suggesting that these features may be involved in a resource partitioning between Apodemus species. The morphological segregation of the species, likely achieved by processes of differentiation in isolation promoted by the complex landscape of China, could contribute to competition avoidance and hence explain why no evidence was found of character displacement. |
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Keywords: | Morphometrics mandible molar Apodemus resource partitioning |
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