Confirming the relationship between body size and perch height in tropical odonates (Odonata: Libellulidae): wet-season contrasts and experimental tests

In a previous study conducted during the dry season at La Selva Biological Station, Costa Rica, mean perch height of libellulid dragonfly species (Odonata: Libellulidae) correlated with male body size, and interactions between species suggested a size-dependent competitive hierarchy. Here, I report on a wet-season study that examined whether seasonal changes in community composition affect…

The effects of wind speed, competition, and body size on perch height selection in a guild of Libellulidae species (Odonata)

For eleven species of sympatric libellulids, male mean mass was positively correlated with wing aspect ratio, wing loading, and mean perch height. We tested the hypotheses that perch height selection was governed by interspecific competition or biomechanical responses to increased wind speed at higher perches. Although larger odonates might prefer higher perches to offset their…

Openwing perching in some Zygoptera (Odonata): a response to Klaus Reinhardt

Herein I respond to a critique of my paper on wing positions in Zygoptera. The author of that critique suggested that most of the hypotheses presented in that paper were flawed and questioned some of the facts brought to bear on them. In addition, he presented his own ideas in support of hypotheses I had…

Competitive interactions affect perch-height preferences of three Odonata taxa (Coenagrionidae, Libellulidae)

Co-occurring odonate species often perch at different heights. We studied the effects of interspecific and intraspecific interactions on perch-height selection by Perithemis tenera, Pachydiplax longipennis, and Enallagma spp. by creating artificial perch stations and comparing perch selection when species perched alone or together. We also compared the frequency of perch-height use in the presence or…

Why do some zygopterans (Odonata) perch with open wings?

Zygoptera show two perching modes, one with wings closed and one with wings open. These perching modes are distributed unequally through the suborder; most Zygoptera perch with closed wings, but species in 43 genera of eight families at least occasionally – in most cases usually – perch with open wings. Alternative hypotheses to explain this…