MEPS 292:195-201 (2005)  -  doi:10.3354/meps292195

Presence of spawn-inducing pheromones in two brittle stars (Echinodermata: Ophiuroidea)

K. Soong1,*, D. Chang1, S. M. Chao2

1Institute of Marine Biology, National Sun Yat-sen University, 70 Lien-Hai Road, Kaohsiung, Taiwan 804, ROC
2National Museum of Natural Science, 1 Kuan-chien Road., Taichung, Taiwan 404, ROC

ABSTRACT: Possible roles of pheromones in inducing spawning of 2 brittle stars, Ophiocoma dentata and Ophiocoma scolopendrina, were tested with gonad homogenates. In both species, the ovary homogenate induced conspecific, competent males to spawn. The potential pheromone was species- specific and had no effect on conspecific females. The testis homogenate did not have any effect. Of the males 50% could be induced at an estimated concentration of 7.8 × 10–7 g ml–1 (wet ovary weight/seawater) with a threshold concentration at 10–8 g ml–1. Some males could be induced to spawn at least 3 consecutive times at 1 d intervals. The unidirectional induction, i.e. males induced by female releasate, suggests high selective pressure of sperm limitation in these 2 species.

KEY WORDS: Pheromones · Brittle star · Spawning · Species-specificity

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