Age-specific behavior and habitat selection of adult male damselflies, Calopteryx maculata (Odonata : Calopterygidae)

We compared the age, movement, and time-activity budgets of male Calopteryx maculata damselflies occupying off-stream tree-fall gaps with those at str eam sites within a 10-ha woodland. All males collected at off-stream sites were younger than males collected at stream sites-as indicated by their sig nificantly higher wing transmittance. Thirty-three percent of teneral males marked at off-stream gaps moved to stream sites within 4 days (mean distan ce = 140 in), while mature males marked at stream sites never left the stre am. In contrast to stream site males, off-stream males spent significantly more time capturing prey and never engaged in aggressive interactions with other males. Behavioral differences were not due to variations in the opera tive body temperature. However, malaise trapping revealed a greater frequen cy of suitable prey in forest light gaps. Our findings support the idea tha t teneral male Calopteryx leave their emergence sites along the stream for off-stream light gaps to forage without interference and build the energy r eserves necessary to attain and hold streamside territories.