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…

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…

Seasonality of prey size selection in adult Sympetrum vicinum (Odonata: Libellulidae)

Sympetrum vicinum is a sit and wait predator, which takes off and pursues small flying insects during its long flying season (July to November). We investigated whether foraging individuals become less discriminating regarding prey size selection during the fall season because the changeable fall weather has an impact on the prey population. To investigate the…

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…

Body temperature regulation in a late-season dragonfly, Sympetrum vicinum (Odonata: Libellulidae)

Body temperature regulation and behavioral responses to temperature variation in the field were investigated in Sympetrum vicinum, a common North American libellulid that is most abundant as a mature adult in autumn. Because of its late flight season, this species is faced regularly with cooler environmental temperatures than most dragonflies investigated heretofore. By virtue of…

Reproductive behaviour of a North African endemic damselfly, Platycnemis subdilatata (Odonata: Platycnemididae) and probable senescence effects

Although the endemic damselfly, Platycnemis subdilatata Selys, 1849, is widespread in the Maghreb, many aspects of its reproductive behaviour, biology and ecology are still unstudied. One particular feature of this species is that its coloration pattern continues to change during maturation and afterwards, which makes it a good model for assessing age effects on behavioural…