A Swedish study reveals that lobsters don't avoid a real fight. Even though USA and Europe are longtime allies, their lobster populations are not uncommon to hostilities.
The aim of this thesis was to study the chemical communication involved in aggressive and reproductive behaviours in the European lobster (Homarus gammarus). Both male and female H. gammarus established and maintained dominance, but the sexes used different strategies for dominance maintenance.
Male losers recognised individual fight opponents and avoided them but fought actively against unfamiliar dominants. In contrast, female losers avoided both familiar and unfamiliar dominants, indicating that they react to the dominance status of the opponent.
Intruding American lobsters (Homarus americanus) have repeatedly been caught in European waters. Since the two species are closely related and have similar food and shelter requirements, aggressive and reproductive behaviours and communication signals may be similar and result in both competition for resources and possibly hybridisation.
Aggressive interactions between male European and American lobsters showed that interspecific communication and dominance maintenance indeed occurs between the two species.