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Meeting Abstract

P1-50   -   Frequency and success of larval clone production in the brittlestar Ophiopholis aculeata McClain, EDH*; Allen, JD; William & Mary, Williamsburg, VA; William & Mary, Williamsburg, VA

Marine community structure is dependent on the recruitment of new individuals; however, an incomplete understanding of life histories hinders the accuracy of recruitment estimates. For example, the assumption that one zygote yields one offspring is violated for many phyla under various conditions. Polyembryony, and specifically larval cloning, is one mechanism by which echinoderms violate this assumption. The daisy brittle star, Ophiopholis aculeata, exhibits three different modes of larval cloning. First, as an 8-arm pluteus, the larva autotomizes the distal portion of its posterolateral arm. The second and third modes are related and both occur during metamorphosis and settlement. In the second mode, one half of the posterolateral arm pair is released and the other half is reabsorbed into the juvenile. In the third mode, the full posterolateral arm pair is released from the juvenile body following settlement. We describe these three modes of cloning and provide details of each. We tracked the frequency of cloning and regeneration success in a population of O. aculeata from Maine. Larvae of O. aculeata cloned via the first mode 7% of the time and were least likely to regenerate. The second mode occurred 6% of the time and half arm pairs were more likely to regenerate. The third mode occurred 79% of the time and full arm pairs were the most likely to regenerate. Only the third mode of cloning has been reported in the literature. We also examined the effects of starvation of early larvae on clone production and the effects of cloning on juvenile quality. Lastly, we confirmed that primary larvae that produced clones were asymmetrical and that secondary larvae, which were the products of cloning events were uniquely pigmented. Both of these observations may allow researchers to identify and analyze this phenomenon in the field and to estimate cloning frequency in nature.