Evolutionary transitions in specialised mating strategies of Nephila spiders - adaption and constraint

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Monogamy is rare and enigmatic in general but monogamy of males in taxa without paternal care is particularly puzzling. Monopolisation of a single female (monogyny) Is the inferred ancestral male mating strategy in the spider genus Nephila. This behavioural strategy is associated with specialised morphological traits that limit males' capacity to re-mate, even if sexual selection should favour switching to a polygynous strategy, In derived Nephila species, such monopolisation attempts are no longer successful, and males have regained their re-matIng capacity in the face of morphological constraints that testify to their specialised past. In this research-project, we compare the mating systems of two Nephila species, representing opposite ends of this transition from monogyny to polygyny. We will Investigate (1) trade-offs between defensive and offensive strategies in a context of sperm competition, (2) how polygyny is reconciled with the constraint of male sperm limitation and (3), how mating prospects and reproductive traits in both sexes relate to environmental conditions within and between species. This approach promises to yield important and novel insights Into the interplay of adaptive processes and constraints in shaping the evolution of mating systems.