[ Back ]


Alternative reproductive tactics in a snail breeding cichlid Lamprologus callipterus

Author Lukas HILKE
Director of thesis Prof. Dr. M. Taborsky
Co-director of thesis
Summary of thesis

In Lamprologus callipterus, a snail breeding cichlid endemic to lake Tanganiyka, three different reproductive tactics are known. The first are territrial nest males, the second one are genetic deterimined dwarf males parasitizing the reproductive efford of the nest males, and the third tactic is a condition dependent tactic of intermediat sized males who try to sneak in and steal ferilisations. As this is a good study system to investigate genetic and condition dependent reproductive tactics in the thesis severel questions will be examined.

First the sperm competition in a symmetric sperm competition experiment will be examined, and sperm parameters such as sperm morphology and sperm swimming performance will be analysed. And the performance of the sperm, as well as the sperm competition outcome will be compared and analysed. Furthermore ther will be an experiement with an asymmetric sperm competition to simmulate natural conditions, and this will be compared with the results from the first experiment.

In the thesis also the frequent dependent success of the different reproductive tactics will be investigated. This will be a long term experiment. In this experiment the success of the three different reproductive tactics in L. callipterus will be studied with differend group compositions in a 7000 liter tank. The ratio between nest males, dwarf males and sneaking males will be changed to see if the composition of the differend tactics as an impact on the reproductive success of each tactic.

Administrative delay for the defence