FACTORS AFFECTING MATE DESERTION BY MALES IN FREE-RANGING CONVICT CICHLIDS (CICHLASOMA-NIGROFASCIATUM)

Convict cichlid fish have biparental care for a period of about 6 week s lasting from egg laying until the young (fry) have grown to about 10 mm. However, the young can sometimes survive with care from only one parent, and desertion of the mate and offspring by males has been obse rved. I tested a theoretical model modified from Lazarus (1990) which predicted that mate and offspring desertion by male convict cichlids s hould be promoted by low predation pressure on fry, high remating oppo rtunities for males, increasing age of fry, and decreasing number of f ry. Males deserted 7.8% of 334 broods studied during two breeding seas ons in Costa Rican streams. As predicted, males deserted their broods most frequently at sites with the highest brood survivorship (lowest b rood predation pressure), when fry were close to independence and when brood size was smaller than average. Sex ratios and interspawning int ervals did not indicate any relationship between mate desertion and op portunities for remating for males. The reuse of spawning caves may fa vor fidelity to the mate and brood, and defending the young from preda tors at the same time as defending the cave from conspecifics may favo r biparental care in this species.