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.
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…
Odonates of small temporary pools, marshes, large permanent ponds, oxbow lakes, dams, and perennial rivers were sampled in the semiarid Chaco biome of NW Argentina between September 2007 and December 2008. Information from 35 localities yielded 60 species; presence/absence information of species was recorded in a spatial-relational database. Alpha, beta, and gamma diversity and total…
Comparative investigations of the distal part of the vesica spermalis (‘glans’) of the anisopteran male secondary copulatory apparatus reveal three different ‘solutions’ of combining the emptying-mechanism of the sperm-reservoir with a ‘washing out’ of sperm of the male predecessor. The responsible apparatus of the glans—actually driven by pressure-changes inside the erectile organ, which is a…
I sampled odonates in pristine lower montane rainforest in Papua New Guinea over several months, recording habitat characteristics for all encounters with adult odonates. Using ordination techniques such as cluster analysis and canonical correspondence analysis I then classified the odonate fauna into assemblages correlated with environmental factors. Within the 2.5 km2 study area I found…
In Norway and throughout the rest of Europe, a continuous decline in the number of small lakes and ponds has taken place. As a consequence, many pond-dwelling organisms have become rare or extinct. Constructed wetlands (CWs) have since the 1990s been used as a remedial action against agricultural runoff. This study has investigated the potential…