Brood care motivation and hunger in the mouthbrooding cichlid Pseudocrenilabrus multicolor.

The interrelationship of hunger and brood care motivation was investigated in the mouthbrooding cichlid Pseudocrenilabrus multicolor from East Africa. In this species the female takes up her eggs during spawning and carries them continuously in her buccal cavity for approximately 10 days (at 27°C). Females with brood in their mouths do not eat. If the brood is removed from the female's mouth at varied times after spawning, brood care motivation (BM) - defined as the readiness to keep brood in the mouth and not to eat it - is maintained for several days (as in most first spawners) or disappears within a few hours (as in most non-first spawners). Hunger - as measured by the amount of Tubifex ingested per unit time - depends on whether the brood-deprived female exhibits BM or not: females without BM eat as much as non-brooding control females. Females with BM eat only approximately half as much. This is true for first spawners as well as for non-first spawners. It can be concluded that a complete physiological anorexia is not needed to prevent brood-eating in mouthbrooding females. A substantial lowering of the general satiation level is sufficient. In addition, stimuli from the brood in the female's mouth totally inhibit food ingestion from outside the mouth during mouthbrooding.