On causation and function of the pre‐spawning behaviour of cichlid fish

This paper reviews studies based on the theory that animal behaviour is organized and controlled by a taxon‐specific ‘software’ design, to which the principles valid for the evolution of morphological and physiological mechanisms equally apply, and which therefore is also subject to adaptive radiation. Causal ethological analysis of the pre‐spawning behaviour of some oral‐ and some substrate‐breeding cichlid species has led to the conclusion that the course of this behaviour, as well as the character of its elements, results from the interaction of at least three mutually‐incompatible behavioural control systems serving, respectively, escape from danger, repulsion of conspecifics (‘aggression’), and attraction of a mate (‘sex’). In the course of pre‐spawning behaviour, the third system gradually gains control over the other two, at least with respect to a particular individual (i.e., the potential mate), losing its effectiveness as a releasing stimulus for aggression and/or escape the more an affinitive individual relationship is built up. In all cichlids, specific motor patterns resulting from the interaction of different sytems in the behavioural organization are functional in selection of the sex‐partner and in preparation of the spawning site. In the sexually dimorphic oral incubators, the form of these activities also differs between the sexes. Performed alternately by male and female, they form a stimulus‐response chain. In contrast, in the monomorphic substrate spawners, in which pair bonds last much longer, these activities are the same in both sexes, which usually perform them simultaneously. In addition to the two functions just mentioned, they serve the establishment of the long‐lasting bond between partners, and the necessary synchronization of their endocrine states for spawning.