Territorial tactics, aggressive interactions, 3 body characters (wing, abdominal and total length), mating success, and the influence of weather conditions were analysed in territorial males. The number of aggressive encounters was positively affected by male abundance and aggression and by weather conditions, also depending on the time of the day. Male abundance was conditioned by territory rank (taken as an index of territory quality). 3 male territorial tactics were discerned, viz. resident, sneaker and floater. Resident males were the most aggressive individuals, and their territories were disputed by sneaker males. Floater males rarely fought. There were no differences in size among individuals using these tactics. A positive correlation existed only between the abdominal and total lengths and the territory rank, but this was probably largely incidental. No size differences were noticed between copulating and non-copulating males. As in other Calopterygidae, the mating system of H. cruentata is a resource-defence polygyny.