Broodcare or Egg Cannibalism by Parents and Helpers in Neolamprologus brichardi (Poll 1986) (Pisces: Cichlidae): a Study on Behavioural Mechanisms

Abstract

AbstractIn the cichlid species N. brichardi the young are tended by parent animals and broodcare helpers. No qualitative differences in the care are apparent. The regulation of eggcare by nonreproductive helpers is of especial interest as it excludes an endogenous component found in the parental care of other cichlids, based on sex and the reproductive cycle.The importance of the factors dominance, territory, size (age) experience, model and the continuous presence of eggs for helper eggcare disposition was examined experimentally. It was shown that subdominant inexperienced young fish will clean clutches, whereas dominants feed on them. Subdominant eggcleaners can be transformed into dominant eggfeeders; the change can be delayed or prevented by the continuous presence of eggs. Subdominant fish in a territory are more inclined to clean clutches than those in an aggregation. With growing experience (or size) helpers orient broodcare behaviour increasingly by a dominant model. Dominance and experience play no part however in broodpairs; here there are sex‐dependent differences. In both sexes, eggcaring behaviour can be evoked only at the beginning of a breeding cycle. The disposition is bolstered by the presence of the clutch, and wanes after egg removal in females faster than in males. The tendency to continue eggcare can be strongly extended in both sexes by the continuous presence of eggs. Comparison with other cave‐breeding cichlids showed that parental eggcare in these and N. brichardi was similarly regulated. Helper broodcare, however, is very differently regulated. These differences are discussed, as well as possible conclusions on the influence of endogenous and exogenous regulatory factors.