Maternal aggression during the mouthbrooding cycle in the cichlid fish, Oreochromis mossamblcus

Oliveira, Rui Filipe; Almada, Vítor Carvalho

http://hdl.handle.net/10400.12/1320

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Authors

Oliveira, Rui Filipe

Almada, Vítor Carvalho

Abstract(s)

Maternal aggression was studied inOreochromis mossambicus during the mouthbrooding cycle. Brooding females were observed in heterosexual captive groups, and their agonistic interactions and behavioural activities were registered. Brooding females were classified into three classes according to the developmental stage of the brood they were incubating: phase 1, brooding eggs; phase 2, brooding fry with yolk-sac; phase 3, brooding fry with exogeneous feeding. The behaviour ofthe brooding females was compared with the behaviour of control non-incubating females. During the brooding cycle females become increasingly more aggressive toward other individuals, with their aggressiveness reaching a peak in phase 3. During the brooding cycle the females also suppress their feeding activities. The outcome of the agonistic interactions (victories-defeats) of the brooding females was positively correlated with the brooding phase but not with clutch size. The main function of maternal aggression inO. mossambicus seems to he the defence of the vulnerable brood against predators, including conspecifics, at a developmental stage when the fry start to forage outside the mother's mouth.