Mate choice and sperm limitation in the spotted spiny lobster, Panulirus guttatus

Abstract

Mate choice by females is influenced by male size, resource provisioning and other proxies for male quality. In decapod crustaceans, mating dynamics are complicated by size-dependent sperm limitation associated with unusually low sperm :egg ratios. We explored how mate size influences mating dynamics in the spotted spiny lobster (Panulirus guttatus), a philopatric species that dwells on shallow and often isolated coral reefs in the Caribbean where choice of mates can be limited. We varied the availability and size of male and female lobsters in a series of laboratory experiments and then quantified courtship behaviour, mate choice and fertilization success of each mating. We found that large males initiated most interactions with other males and won 99% of those encounters. Large males were also more successful in garnering mates, but males of all sizes attempted to mate with all sizes of females. Females nearly always (92% of trials) chose males larger than themselves. However, if large males were unavailable, females mated with smaller males, which resulted in reduced fertilization success. Thus, for species like P. guttatus that dwell in patchy habitats with limited mate availability, the optimal strategy for mate choice is context-dependent, although not without cost to the largest females.

Keywords:

• Sperm limitation
• Panulirus guttatus
• mating behaviour

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Acknowledgements

We would like to thank our colleagues C. Acosta, J. Schratwieser, D. Behringer, W. Sharp, and R. Bertelsen for their assistance with the field work, along with A. MacDiarmid and B. Herrnkind for advice. This study was supported by awards to M. Butler from the US National Science Foundation (OCE-9730195), NOAA National Undersea Research Program (9913), and Florida Sea Grant (R/LR-B-38).

Notes

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark