Size-assortative mating and sexual size dimorphism are predictable from simple mechanics of mate-grasping behavior

BMC Evolutionary Biology

Research Article

Piotr G Jablonski¹  Chang S Han²  Beobkyun Kim³  Frank C Park³ 

[1] Laboratory of Behavioral Ecology and Evolution, School of Biological Sciences, Seoul National University, Seoul, South Korea;Centre for Ecological Research, Polish Academy of Sciences, 05 092, Dziekanów LesnyŁomianki, Poland;Laboratory of Behavioral Ecology and Evolution, School of Biological Sciences, Seoul National University, Seoul, South Korea;School of Biological, Earth, and Environmental Science, The University of New South Wales, 2052, Sydney, New South Wales, Australia;School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, South Korea;

关键词: Sexual Size Dimorphism;    Male Size;    Selection Gradient;    Male Mating Success;    Male Body Size;   

DOI  :  10.1186/1471-2148-10-359

 received in 2009-08-09, accepted in 2010-11-20,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundA major challenge in evolutionary biology is to understand the typically complex interactions between diverse counter-balancing factors of Darwinian selection for size assortative mating and sexual size dimorphism. It appears that rarely a simple mechanism could provide a major explanation of these phenomena. Mechanics of behaviors can predict animal morphology, such like adaptations to locomotion in animals from various of taxa, but its potential to predict size-assortative mating and its evolutionary consequences has been less explored. Mate-grasping by males, using specialized adaptive morphologies of their forelegs, midlegs or even antennae wrapped around female body at specific locations, is a general mating strategy of many animals, but the contribution of the mechanics of this wide-spread behavior to the evolution of mating behavior and sexual size dimorphism has been largely ignored.ResultsHere, we explore the consequences of a simple, and previously ignored, fact that in a grasping posture the position of the male's grasping appendages relative to the female's body is often a function of body size difference between the sexes. Using an approach taken from robot mechanics we model coercive grasping of females by water strider Gerris gracilicornis males during mating initiation struggles. We determine that the male optimal size (relative to the female size), which gives the males the highest grasping force, properly predicts the experimentally measured highest mating success. Through field sampling and simulation modeling of a natural population we determine that the simple mechanical model, which ignores most of the other hypothetical counter-balancing selection pressures on body size, is sufficient to account for size-assortative mating pattern as well as species-specific sexual dimorphism in body size of G. gracilicornis.ConclusionThe results indicate how a simple and previously overlooked physical mechanism common in many taxa is sufficient to account for, or importantly contribute to, size-assortative mating and its consequences for the evolution of sexual size dimorphism.

【 授权许可】

Unknown   
© Han et al; licensee BioMed Central Ltd. 2010. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.