a b s t r a c t
Article history:
Received 31 July 2009
Received in revised form 12 February 2010
Accepted 26 May 2010
Keywords:
Reproductive success
Mate choice
Colour
Assortative mating
Nile tilapia
Oreochromis niloticus
Red tilapia stocks have been developed for aquaculture from rare colour mutations. This study was carried
out to discover if male body colour (wild type or red) influences mating success in the Nile tilapia
(Oreochromis niloticus), by allowing females to choose between wild type and red males under semi-natural
spawning conditions. In a series of eight trials, ten females (wild type females in four trials, red in the other
four) were placed in an arena tank with two size-matched males, one wild type and one red. Each trial ran
for 5 weeks, during which fish were allowed to spawn and eggs were collected from the mouths of the
females after spawning. Paternity was assessed using microsatellite genotyping and phenotype scoring.
Where both males contributed to a batch of fry from a single female, the batch was allocated to the “primary”
sire for statistical analysis. No significant departures from equal mating success as the primary sire were
observed between red and wild type males. However, there was a significant difference between the red and
wild type females in the frequency of secondary paternal contribution to egg batches. These results are
discussed with reference to spawning of Nile tilapia in natural and aquaculture environments.