Piracy mating by large males in a monogamous substrate-breeding cichlid inLake Tanganyika

Telmatochromis temporalis is a biparental substrate breeding cichlid that m ates in size-assortative monogamy at the southern end of Lake Tanganyika. I n this population, at least a few months before the rainy season, large mal es (90-110 mm TL) did not pair. However, they maintained large territories that were defended against conspecific large males and that contained sever al pairing small males (50-80 mm). Large males occasionally visited the nes ts of the small pairs in their territories, and selectively took over the n ests by attacking the owner male. During the takeover, the large males cour ted the small females in the nests and might have ejaculated sperm. After t he large males left the nests, the small owner males conducted paternal car e at the nests. These behaviour patterns of large males are similar to pira cy mating reported in ether polygamous fish species. The piracy mating of l arge male T. temporalis seems to be an alternative tactic when large female s are not available.