Nest deprivation and mating success in Nile tilapia (Teleostei: Cichlidae)

We tested the effect of nest deprivation on the mating success and sexual selection of dominant Nile tilapia males in two treatments, consisting of two males and three females kept on aquarium with or without nesting substrate (INS: with substrate inside, N = 9; NOS: non-substrate inside, N = 11). Other male traits potentially affecting mating success, such as aggressiveness level, courtship investment, and condition factor were also analyzed. The dominant male's behavior was video-recorded in four 20-min sessions: 1, 4, 7, and 10 days after grouping. Latency to spawn and spawning frequency were similar in WS and NS groups, showing the same mating success among dominant males on the presence or absence of gravel. Nest investment was the main factor related to female choice in INS groups, but none of the other variables improved mating success in NOS.Although nesting is related to sexual selection in Nile tilapia,gravel substrate deprivation from which they construct a nest does not affect mating success. This finding may explain the reproductive success of the species in a wide range of environments and aquaculture systems.