FACTORS INFLUENCING PAIRBOND STABILITY IN CONVICT CICHLIDS (CICHLASOMA-NIGROFASCIATUM)

In isolated pairs of the biparental convict cichlid (Cichlasoma nigrof asciatum) caring for fry, pairbonds can be broken by removal of the fr y. Within three hours, the mates of many pairs become so mutually aggr essive that the female finally flees from her larger mate, who chases her. The pairbond is mended within seconds upon re-introduction of the fry. Yet removal of young leaves some pairs little or not at all affe cted. They seem to have more stable pairbonds, Multiple regression of data from 39 pairs on a quantitative measure of pairbond destruction r evealed support for the so-called parity-hypothesis, which holds that a cichlid pair is compatible only when the female's aggressiveness com pensates for her smaller size. The size of the female relative to the male's, and her aggressiveness relative to his in the undisturbed situ ation, proved positive predictors of pair stability in the fry stage, Thus the same factors which have earlier been shown to favour pair for mation in other biparental cichlids seem also responsible for pair sta bility in a later stage of the reproductive cycle. (C) 1997 Elsevier S cience B.V.