Male competition and female choice in Padogobius martensi (Pisces, Gobiidae)

Abstract In natural populations of Padogobius martensi , a small freshwater goby, the number of eggs per nest increases with the size of the guarding male. The present study is a laboratory investigation of factors determining this size-related reproductive success of males. Females mated randomly with respect to male size but showed a marked preference for spawning in large nest sites, which were always occupied by the larger males. Courtship interference, nest take-over and egg cannibalism reduced the reproductive success of smaller males, although the progeny of some small males were guarded by the larger males that took over their nest.