Polymorphism in coenagrionids is widely known, mainly for Ischnura. Here, we present the case of I. capreolus, a Neotropical species of which, until now, little information concerning color polymorphism and ontogenetic color changes was known. We used a marking and recapture method to evidence ontogenetic coloration changes in females. We show that, in addition to…
Our goal was to investigate whether the loss of riparian forests alters the structure of assemblages and populations of dragonflies and damselflies. We tested the hypothesis that the composition of the odonate assemblages found upstream from dams are significantly different from those found downstream of these barriers. To test the hypothesis, we investigated stream sectors…
In Venezuela, the “metallic group” includes three species: Argia cupraurea Calvert, Argia jocosa Hagen in Selys, and Argia orichalcea Hagen in Selys. These are here diagnosed and illustrated, and their distribution in Venezuela is mapped. The larva of A. jocosa differs from the few other known larvae of the group in details of the prementum,…
Clutch size is an important fitness component often quantified artificially by inducing oviposition in libellulid females. Female behavior and egg production of the yellow-veined skimmer, Orthetrum nitidinerve, were studied in northeast Algeria during its reproductive season. Data on reproductive behavior and biology of this Mediterranean endemic species has not been published previously. Males guarded territories…
Detailed descriptions and illustrations are provided of the ultimate instar larvae of Argia medullaris and Argia variegata from Colombia. The principal features are outlined and compared with other species. Argia medullaris differs from other species of the genus by the parallel width of the lateral gills and prominent ligula; the A. variegata larva can be…
Anisoptera emergence in the seasonal tropics was monitored at a 35-ha managed wetland site in Hong Kong from February 2004 to November 2007. Exuviae records of 18 species from multiple emergence screens, exuviae traps and transect surveys were combined. The presence of adults during this period was also monitored. The study site comprised a mosaic…
During a period of nine years, from 2000 to 2008, two consecutive studies—one focusing on observations of adult Odonata, the other on collection of larvae—were carried out in the basin of the Guadiamar River in the southwestern Iberian Peninsula. In addition to monitoring Odonata, several environmental variables were assessed, including an index based on macroinvertebrate…
In this study we use high resolution SEM to describe the diversity of wax crystals and their distribution on different morphological structures in male individuals of Calopteryx splendens. The entire cuticle surface of this damselfly, with the exception of ommatidia and ocelli, is covered with crystalline wax in dimensions from submicron to micron range. It…
Due to the destruction of its primary habitats, the West Palaearctic libellulid Orthetrum coerulescens has suffered much decline in central Europe. However, at the regional scale it has survived in a variety of secondary habitat, such as draining ditches. In order to find adequate measures for its conservation and promotion, habitat use and habitat recognition…
The status of the Odonata as a model taxon for studying the evolution and diversity of reproductive behaviours is shown here to have declined relative to crickets and Drosophila. Very few available data on ejaculate size, the number of sperm stored by females and the duration of sperm storage reveal poor knowledge of these areas…