Mating behaviour of the marine turbellarian Macrostomum sp.: these worms suck


Simultaneous hermaphrodites experience unique conflicts of interest during reproduction, some of which are reflected in their complex mating behaviours. We here provide the first detailed description of the mating behaviour of a marine flatworm of the genus Macrostomum, a cosmopolitan group of microturbellaria. Mating in this species is usually initiated by the precopulatory behaviours circling and reeling, then leads to reciprocal copulation where worms mutually insert their copulatory stylet, and often ends in an intriguing postcopulatory sucking behaviour. We provide detailed data on the frequencies and durations of the different behaviours, and examine some biotic and abiotic factors that could influence the mating rate. We further speculate on the function of sucking and suggest that it could be an adaptation for the digestion of sperm and/or the removal of seminal components, which may function as allohormones.

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We would like to thank M. Fasel for artwork and P. Ladurner for the sperm picture. P. Ladurner, N. Michiels, R. Rieger and D. Vizoso provided helpful discussion and comments on the manuscript. L.S. would further like to thank N. Michiels for his hospitality. During this study L.S. was supported by an IHP-fellowship (SNF, Switzerland) and a L.-Meitner-fellowship (FWF, Austria). Animal experimentation was carried out in accordance to German legal and ethical standards.

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Correspondence to L. Schärer.

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Communicated by O. Kinne, Oldendorf/Luhe

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Schärer, L., Joss, G. & Sandner, P. Mating behaviour of the marine turbellarian Macrostomum sp.: these worms suck . Marine Biology 145, 373–380 (2004) doi:10.1007/s00227-004-1314-x

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  • Mating Behaviour
  • Sperm Transfer
  • Female Opening
  • Observation Chamber
  • Copulation Rate