Summary
Male Nannothemis bella (Uhler) dragonflies are territorial at the breeding site. On the basis of the male behavioural time budgets, the species can be regarded as a territorial percher. Those acts involved in territorial maintenance (patrolling and fighting) are more closely related to territorial dimensions than are those not concerned with the territory (feeding). Territoriality appears closely related to some aspect of the water area within a territory, as maintenance and defence behaviour vary most consistently with the size of this area. Territorial size increases as the season progresses. Defensive behaviour is directed at both conspecifics and a heterospecific, Leucorrhinia frigida. The usefulness of a marking technique for dragonflies was tested statistically.
Methodology
Study site.
The study site was located at the southern border of Hebert bog, 15 km west of Queen's University Biological Station located on Lake Opinicon, Chaffey's Locks, Ontario, Canada. The site was a 100 by 48 m area of mat of a typical Sphagnum bog. Nannothemis bella males localized around numerous small pools in the mat surface. Individual territories were mapped, using a grid of 4 x 4 m quadrants. Observations Individual N. bella were marked using Connor's (197 1) technique, but we substituted a fine artist's brush for the syringe. Approximately 500 individuals of each sex were marked by early July 1981. The population census was recorded after 0900 at roughly 2-day intervals. For each localized male, sperm translocation, perching bouts, patrols, feeding bouts, male - male interactions, and male - female interactions were noted. In male-female interactions, bouts of courtship, precopulatory tandem, copulation, postcopulatory tandem, and guarding were timed. Details of male-male interactions were derived from subcategories of bouts of lunges, chases, circle flights, and spiral flights. - Frequencies and durations of N. bella male acts were recorded across four time periods: (i) 0600-0900; (ii) 0900- 1200; (iii) 120-1500; and (iv) 1500- 1800. Each of 60 localized males was observed for at least 2 h. Four different time budgets, each of 2 h duration, were monitored for use in building an ethogram. To attain a measure of territorial size and maintenance, positions of perches in a territory and the flyway around it were noted on maps for each of 60 males.