Recent studies have shown that differences in life history may lead to consistent inter-individual variation in behavioural traits, so-called behavioural syndromes, animal personalities or temperaments. Consis- tencies of behaviours and behavioural syndromes have mainly been studied in non-cooperative species. Insights on the evolution of coopera- tion could be gained from studying individual differences in life histories and behavioural traits. Kin selection theory predicts that if an individ- ual’s reproductive ability is low, it had to aim at gaining inclusive fitness benefits by helping others. We tested this prediction in the cooperatively breeding cichlid Neolamprologus pulcher, by assessing reproductive parameters of adults that had been tested earlier for aggressiveness and for their.
