Table of Contents
International Journal of Evolutionary Biology
Volume 2012, Article ID 517849, 10 pages
http://dx.doi.org/10.1155/2012/517849
Research Article

Spawning Coordination of Mates in a Shell Brooding Cichlid

1Department of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Wohlenstr 50a, 3032 Hinterkappelen, Switzerland
2Division of International and Environmental Health, Institute of Social and Preventive Medicine (ISPM), University of Bern, Finkenhubelweg 11, 3012 Bern, Switzerland
3Clinical Trials Unit Bern, Department of Clinical Research, University of Bern, Finkenhubelweg 11, 3012 Bern, Switzerland

Received 20 January 2012; Revised 27 April 2012; Accepted 26 May 2012

Academic Editor: Tetsumi Takahashi

Copyright © 2012 Dolores Schütz et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Aim. External fertilisation requires synchronisation of gamete release between the two sexes. Adequate synchronisation is essential in aquatic media because sperm is very short-lived in water. In the cichlid Lamprologus callipterus, fertilisation of the eggs takes place inside an empty snail shell, where females stay inside the shell and males have to ejaculate into the shell opening. This spawning pattern makes the coordination of gamete release difficult. Methods. This study examined the synchronisation of males and females during egg laying. Results. The results showed that the male initiates each spawning sequence and that sperm release and egg laying are very well synchronised. 68% of all sperm releases occurred at exactly the same time when the female laid an egg, and 99% of ejaculations occurred within ±5 seconds from egg deposition. On average 95 eggs are laid one by one with intervals of several minutes between subsequent eggs, leading to a total spawning duration in excess of six hours. Conclusions. We discuss this exceptional spawning pattern and how it might reflect a conflict between the sexes, with males attempting to induce egg laying and females extending the egg laying period to raise the chance for parasitic males to participate in spawning.