Distributional Patterns and Their Interpretation in Hetaerina (Odonata: Calopterygidae)

Abstract

The geographical distribution, north of Mexico, for damselflies in the genus Hetaerina appears by county for each state and nearest community for 2 Canadian provinces. Hetaerina americana (Fabricius), H. titia (Drury), and H. vulnerata Hagen occur in 41, 24, and 4 U.S. states respectively, and H. americana exists also in Quebec and Ontario, Canada. Likely explanations of these geographic patterns follow the distributional data. Temperature probably controls the northern limits in H. americana and H. titia; adult behavioral preferences affect western limits of H. titia; drought severely limits distribution of H. vulnerata in the southwestern U.S. A well-isolated, pleistocene relict describes the single Florida colony of H. americana. Isolated colonies of H. americana also characterize part of its southwestern distribution. Flight season data show a 12 month adult activity period in tropical climes dropping to an approximately 3 month interval in northern colonies of H. americana, and an even shorter time in populations of northern H. titia.