Flexibility of reproductive tactics and their consequences in the brood parasitic fish Pungtungia herzi (Teleostei: Cyprinidae).

ABSTRACT

Although previous studies have claimed that Pungtungia herzi (Cyprinidae) is an obligate brood parasite, in this study a significant proportion of P. herzi egg masses was found in crevices formed by stones and rocks, which was not guarded by hosts. Egg masses were also found in almost all nests of a goby Odontobutis obscura, suggesting that P. herzi has two alternative reproductive tactics brood parasitic spawning and non-parasitic crevice spawning, the latter of which may occur when a shortage of reproductive resources (i.e. host nests) exists. The hatching rates of parasitic egg masses were significantly higher than those of non-parasitic egg masses, and the hatching rate of P. herzi eggs exhibited a strong positive correlation with continuous egg guarding by a reproductive O. obscura male. These results indicate that brood parasitism effectively improves reproductive success in P. herzi. The alternative reproductive tactic of this species suggests that brood parasitism has evolved directly from crevice spawning via the sharing of spawning habitat with host species.