Our study evaluated the effects of environmental variables on the assemblages of the suborder Zygoptera, and tested the hypothesis that environmental variables are more important determinants of the structure of these assemblages than limnological variables in streams. We sampled 17 streams in the Carajás National Forest and tested our hypothesis using a linear regression analysis, with the zygopteran species composition, richness, and abundance as the response variables.
The Indian Elattoneura are a difficult group to identify due to their extreme morphological similarity and sparse information in identification keys and on geographical distribution. The ambiguity is prominent among two Peninsular Indian Elattoneura species, E. nigerrima (Laidlaw, 1917) and E. tetrica (Laidlaw, 1917), described a hundred years ago.
Many insects including odonates thermoregulate using a combination of behavioral and physiological mechanisms. At high ambient temperature (Ta), these mechanisms include decreased heat production and increased heat loss. Heat production can be reduced by decreasing activity. Heat loss can be enhanced by perching in a shaded microhabitat where temperature is cooler than in the surrounding environment.
As warm-adapted insects of tropical origin, Odonata cope with cold periods by seasonal regulation and diapause. A model for larval-overwintering species is proposed with three response patterns related to the timing of emergence, which can be predicted from seasonal cues during the last few stadia. For emergence during the present season, there is an often time constrained pre-emergence development, accelerated by long days and higher temperatures.
Nearly every dragonfly species around the world has now been assessed against the IUCN Redlist criteria revealing that 16% of species are at risk of extinction.
The fluid dynamics of aerodynamic force control in insects depends on how oscillating wings interact with the surrounding air. The resulting flow structures are shaped by the flow induced by the wing’s instantaneous motion but also on flow components resulting from force production in previous wing strokes and the motion of other wings flapping in…
Taxonomic, morphological and distributional data on three species of the rare South American corduliid genus Lauromacromia Geijskes, 1970 are updated based on specimens collected recently and old specimens deposited in natural history collections. The female of the poorly known Lauromacromia luismoojeni (Santos, 1967), an endemic species from the Brazilian Cerrado, is illustrated, described and diagnosed…
From their earliest appearance in the fossil record, dragonflies have clearly taken a different approach to flight than other insect groups. Even the superficially similar Neuroptera do not fly like dragonflies. Flight specialisation has enabled dragonflies to occupy a range of niches, as specialised predators of flying insects, for around 300 My.
Insect wings have no flight muscles, except those situated in the thorax. However, they continuously respond to forces acting on them during flight. This ability is achieved by the specialised design of the wings and plays a key role in their aerodynamic performance. Dragonfly (Anisoptera) wings represent an extreme example of this automatic shape control…
Dragonflies and damselflies (the Odonata) are among the most efficient flying insects. However, fragmentation of the landscape can increase distance between habitats and affect costs of dispersal, thus shaping phenotypic patterns of flight-related traits, such as wing shape, wing loading and wing size. Urban landscapes are highly fragmented, which limits dispersal among aquatic habitats. Hence,