Visiting Behaviour by Females of the Sexually Dichromatic Damselfish, Chrysiptera cyanea (Teleostei: Pomacentridae): a Probable Method of Assessing Male Quality

Authors


A-08, Dept. Zoology, University of Sydney, Sydney, NSW 2006, Australia.

Abstract

The process of female choice of mates was examined in the damselfish Chrysiptera cyanea. Females make their choices during courtship periods termed “visiting” which are performed the day prior to spawning. Each female spawns once every four days; the eggs take four days to hatch. Female spawning is asynchronous. Males may therefore have eggs in all stages of development in their nests simultaneously. Females were shown to rely on apparent male reproductive status (whether or not there were eggs in the nest at the time of visits) when choosing spawning partners. Secondarily, courtship levels, male size, and the colour pattern of males appeared to influence choice. Among successful males, estimates of male reproductive success were correlated with the operative sex ratio (females to successful males) and the percentage of the eggs received which remained on day 4, just prior to hatching (estimated parental care ability). The first factor contributes in a direct manner to male reproductive success. The second is probably a result of differential reproductive success and not a cause of it. Eggs in nests with a large number of eggs had a higher hatching success than those in nests with fewer. Females therefore pursue a copying strategy, preferentially laying their eggs with those of other females. Thus eggs appear to be a valuable commodity from the viewpoint of the males. Unsuccessful males readily foster eggs, regardless of their source, in what is effectively a “cheating” strategy.

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