FEMALE SAND GOBIES GAIN DIRECT BENEFITS BY CHOOSING MALES WITH EGGS IN THEIR NESTS

In some fish species with paternal care, females prefer to spawn with males whose nests already contain eggs. Several hypotheses have been p ut forward to explain this behaviour, such as reduced risk of predatio n or cannibalism (the dilution effect), increased parental investment, and mate copying. This experimental study focuses on female mate choi ce in the sand goby, Pomatoschistus minutus. Females were found to cho ose males with eggs in their nests. In addition, hatching success incr eased with clutch size, mainly because males with larger clutches show ed less filial cannibalism. Increased egg survival in large clutches m ay thus be explained by a combination of the dilution effect and highe r parental investment. In another experiment, females did not seem to copy the observed mate choice of other females. In conclusion, female preference for males with eggs in their nests is adaptive, and can be explained by direct benefits, as more surviving offspring are produced .