Differential investment in the Banggai cardinalfish: can females adjust egg size close to egg maturation to match the attractiveness of a new partner?

Abstract

To test whether females can change their egg investment according to the different attractiveness ( i.e. size as measured by standard length,Ls) of a new mate after eggs have already matured in response to an earlier mate, female Banggai cardinalfishPterapogon kauderniwere first allowed to produce eggs for small (unattractive) or large (attractive) males. Then, when spawning was initiated, but prior to actual spawning, their partner was switched to either a significantly larger or a significantly smaller partner, respectively. A strong positive correlation between egg size and days until spawning with the second male was found for the females initially paired to a small and then a large male. Within a few days, these females apparently increased their egg size to match the attractiveness of their new male. No correlation between days until spawning and egg size in females initially paired to a large and then a small male, however was found, so apparently females were unable to adjust egg size in response to a decrease in mate attractiveness. Consequently, it is suggested that females can increase their egg size investment even after the onset of egg maturation and that this change can be quite rapid.