Stratégies comportementales de reproduction chez les animaux

Biological diversity often refers to species counts but it also encompasses the amazing displayed reproductive strategies. Males and females exhibit adaptations which are not necessarily associated with the production of gametes. This sexual dimorphism is in part due to sexual selection, i.e. mate choice and competition within the sexes. The use of sometimes complex models allows to highlight the adaptive signification of strategies and then to explain their exhibition in varied situations. Each species is characterised by the existence of specific traits, but within each species, males and females are not constrained to exhibit a stereotyped strategy. In function of their phenotypic peculiarities and the surrounding environment, both sexes can opt for behavioural alternatives that optimize their reproductive success. This plasticity can lead to the exhibition of particular displays but also to the formation of monogamous or polygamous breeding systems. Selection does not stop at the reproductive act as varied strategies can favour a sexual partner over another one in a sexual conflict which can be pronounced, but which can also have bilateral advantages. Such a sperm competition – as acting at the gamete level – can result in sperm male precedence by the exhibition of guarding behaviour, physical or chemical manipulations and also by cryptic sperm choice.