ABSTRACT.1Male spacing, aggression, and female visitation are described for a lek ofDrosophila cnecopleuraHardy within a Hawaiian rainforest. The lek was located at a single tree ofPisonia umbellifera, and the males present defended individual leaves as mating territories. Observations were made in October 1986 and April 1987.2Approximately twice as many males were present at the lek in October than in April. At both times, males generally perched on the lowest leaves in the lek. Individuals did not remain on particular leaves for long periods of time but frequently moved among different territories.3Males engaged in two types of aggressive encounters, face‐offs and chases, and in all encounters the resident displaced the intruder.4Females were sighted at the lek 0.69 times/h in October and 0.23 times/h in April. Most of the leaves visited by females were among the lowest in the le