Effects of some ecological factors on a late summer community of adult Odonata

A community of adult Odonata, composed of 15 species, was studied from 7 August 1975 until 17 November 1975 at a small pond in piedmont North Carolina. Studies were made on adult behavioral patterns including flight, reproductive, and perching activity in relation to ambient temperature, light intensity, and time of day. The frequencies of intra and inter-specific interactions were recorded for the most abundant species. Most species initiated their flying periods by mid-day and terminated them by 1900 hrs with considerable variation among the species. Perching activity varied inversely with the incidence of mid-morning to afternoon flight period for most of the libellulids. A general reduction in the total flight period was observed for most species as the photoperiod gradually decreased throughout the study period. Maximum reproductive behavior in a given day occurred near the middle to latter part of the patrolling period. Minimal temperature thresholds for activity ranged from 20 - 26°C in August compared to 16 - 26°C in September. A diurnal cycle of attendance at water for most female Odonata occurred at a higher temperature and at a later time of day than for their male counterparts. Intraspecific interactions, usually between males, were much more common than interspecific interactions. Threat behavior was much more prevalent during August when relative numbers of individuals in the community were high