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

Abstract

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.

Motivation and time of day affect decision-making for substratum granulometry in the Nile tilapia Oreochromis niloticus

“…A similar effect was described by Mendonc¸a et al (2010), who reported that male O. niloticus visited different substrata (sand, shell, stones and glass) at similar rates, but nested preferentially on sand. As this kind of excavation (nesting) is used by O. niloticus for attracting females and laying eggs (Mendonc¸a and Gonc¸alves-de-Freitas, 2008), Mendonc¸a et al (2010) concluded that preferential nesting on sand indicates that the male Nile tilapia reproductive condition affects the choice of substratum type. In the present study the fish reproductive condition was not evaluated; however, 14 of 15 fish dug one type of river substratum, a reproductive behavior usually associated with reproductive status.…”

“…(), who reported that male O. niloticus visited different substrata (sand, shell, stones and glass) at similar rates, but nested preferentially on sand. As this kind of excavation (nesting) is used by O. niloticus for attracting females and laying eggs (Mendonça and Gonçalves‐de‐Freitas, ), Mendonça et al. () concluded that preferential nesting on sand indicates that the male Nile tilapia reproductive condition affects the choice of substratum type.…”

“…Proper substratum has been shown to enhance growth, production, survival (Uddin et al., ) and reproduction (Takemon and Nakanishi, ; Galhardo et al., ) in Nile tilapia and other Cichlidae. Moreover, the Nile tilapia prepares nests for mating by digging in the substratum, a behavior affected by the type of bottom available (Mendonça and Gonçalves‐de‐Freitas, ). More importantly, because the Cichlidae use their mouths to dig, the particle size of the substratum might be relevant.…”

Visual communication stimulates reproduction in Nile tilapia, Oreochromis niloticus (L.)

“…Reproduction can take place even in the absence of nest (27). Thus, the environmental structure of the present study might have stimulated females to build nest.…”

Substratum choice for nesting in male Nile tilapia Oreochromis niloticus

“…Fish position was registered based on the placement of the fish's eye inside the substratum quadrant. A nest was defined as an excavated area in any of the three substrata sufficient to allow nesting, as previously described (Mendonça & Gonçalves‐de‐Freitas, 2008). As male position could be influenced by female location, the position of both males and females was analysed.…”