Mate choice in temperate and tropical spiny lobsters with contrasting reproductive systems

Abstract

Sperm limitation of reproductive success is common in decapod crustaceans, favouring mating systems in which females compete for large males of high reproductive value. We investigated these phenomena in two species of spiny lobsters - one temperate, one tropical - with contrasting reproductive systems: the Southern Rock Lobster (Jasus edwardsii) and the Caribbean Spiny Lobster (Panulirus argus). We hypothesized that female mate selection should be more pronounced in the temperate J. edwardsii than in the tropical P. argus because J. edwardsii matures later, has a shorter mating season, and produces just one clutch of eggs per year that benefit from significant maternal investment of resources. As hypothesized, experiments conducted in large mesocosms revealed that female J. edwardsii cohabited with large males more often than expected by chance during their receptive period, but not at other times. Large male J. edwardsii cohabited in dens with the largest unmated females, whereas small males exhibited no mate size preference. In contrast, the proportion of female and male P. argus that co-occupied dens with the opposite sex was no more than expected by chance. Cohabitation patterns in the wild supported these laboratory findings for both species. Our results demonstrate the tight connection between contrasting reproductive strategies and the specificity of mate choice in spiny lobsters that are consistent with predictions based on environmental seasonality in temperate vs. tropical ecosystems.