Reproductive ecology of yellow-bellied toads Nectar intake and energy expenditure in a flower- visiting bat Other projects Aggression in Cichlid fish For some time, the behaviour of the Orange Chromide (Etroplus maculatus), an Asian cichlid fish, was used as evidence for an endogenous production of aggressive energy. This was based on the observation that male-female pairs will breed successfully if they can regularly attack neighbours. In contrast, isolated pairs were said to break up because the only opportunity for the partners to let their increasing aggressive steam off was to fight against each other. In my PhD thesis I could not only refute the pair split in isolation; I also showed experimentally that increased aggressiveness is better explained through external stimulation than through the assumed endogenous accumulation of aggressive energy. Wild boars: Population dynamics and damage Etroplus maculatus