We compared the prevalence and intensity of Arrenurus sensu stricto water mite parasites on Enallagma civile Hagen in Selys, 1853 (Zygoptera: Coenagrionidae) from 10 freshwater wetlands (playas) in two different land-cover contexts in western Texas from 2006-2007.
Urbanization has considerable impacts on stream ecosystems. Streams in urban settings are affected by multiple stressors such as flow modifications and loss of riparian vegetation. The richness and abundance of aquatic insects, such as odonates, directly reflect these alterations and can be used to assess urban impacts on streams.
The final instar larvae of the two species of the southern African gomphid genus Ceratogomphus, the South African endemic C. triceraticus and the more widespread C. pictus, are compared based on exuviae. Main differences are the shapes of the prementum and of the last abdominal segments, giving C. pictus a more slender and pointed appearance.
The growth of agricultural and mining activities in the Amazon has impacted land-use and caused significant changes in the local environmental conditions of streams. In the face of these changes, our study aimed at assessing how environmental changes affect Odonata larval assemblages in streams in the eastern Amazon.
Odonata (dragonflies and damselflies) are efficacious for management and conservation efforts in freshwaters. In recent times, increased effort has gone into enhancing awareness, data and information on dragonflies among scientists and policymakers.
We investigated the odonates of Wadi Cherf, a tributary of Wadi Seybouse, and explored the main environmental factors that may be important drivers of the abundance and diversity of Odonata assemblages. PCA analyses demonstrated a significant altitudinal gradient associated with water flow, temperature, vegetation cover, substrate and adjacent land use. Notably, pollution was a dominant…
This study investigated the biological water quality and Odonata assemblages in three waterbodies in Ilara-Mokin, with the aim of determining the ecological integrity of the ecosystems. Sampling of Odonata specimens was carried out over April–August, 2017 between 9.00am and 4.00pm under favourable conditions. Some physico-chemical parameters of the water such as dissolved oxygen, electrical conductivity,…
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,…