MEPS 230:119-126 (2002)  -  doi:10.3354/meps230119

Patterns of sexual and asexual reproduction in the brittle star Ophiactis savignyi in the Florida Keys

Tamara M. McGovern*

Department of Biological Science, Florida State University, Tallahassee, Florida 32306-1100, USA
*Present address: Friday Harbor Laboratories, 620 University Rd, Friday Harbor, Washington 98250, USA. E-mail:

ABSTRACT: Many plant and animal species reproduce both sexually and asexually. These 2 reproductive modes are both likely to be costly and, in many species, they occur at different times of the year. Here, I present information on the sexual and asexual reproductive biology of the brittle star Ophiactis savignyi (Echinodermata, Ophiuroidea) in the Florida Keys, USA. Small brittle stars (less than 3 mm) are almost always non-mature, and non-mature individuals are more likely to have recently undergone clonal division than mature brittle stars. Males appear to have a lower size threshold for sexual maturity than do females, but the sexes do not differ in the recency of clonal division. The greatest proportion of mature brittle stars was observed in the late summer through fall in all 3 years of the study. The incidence of asexual reproduction increases in the late fall through late winter. It therefore appears that brittle stars are more likely to split after the sexual reproductive season. The onset of cloning as the sexual reproductive season ends may result from differences in the time of year in which each mode confers the greatest fitness benefit or may arise from energetic trade-offs between the 2 modes of reproduction.

KEY WORDS: Asexual reproduction · Sexual reproduction · Ophiactis savignyi · Size at reproduction · Seasonality

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