Forests have been widely recognized as key habitats for odonate (dragonflies and damselflies) biodiversity, but the importance of forests for holding odonate biodiversity remains understudied in tropical mountains, one of the most diverse ecosystems on the planet. Here we describe the odonate assemblage composition along the elevation gradient in the Tatamá Mountains (Colombian Cordillera Occidental).
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,
Damselflies adapted to forest habitats are expected to be negatively affected by the disturbance of riparian forests, due to the change in insolation when trees are cleared. In this paper, we compare survivorship and behaviour of two populations of Heteragrion cooki by means of mark-recapture methods and focal observations of adults. We found similar densities…
Assessment of conservation status is a necessary step before management plans can be formulated. Historically such assessments have a strong bias toward vertebrates, particularly endothermic terrestrial vertebrates (i.e. birds and mammals). Invertebrates, by contrast, tend to be ignored, and many insect groups, despite being species rich and reasonably well studied, such as the Odonata (damselflies…
Although the sex ratio of Odonata at emergence has received much attention, we are still far from understanding the exact causes of its variability and imbalance. In this paper we studied the sex ratios at emergence in natural populations of two Gomphus species based on samples of exuviae taken from two European lowland rivers. We
We studied a population of Polythore procera along a stream in the Colombian eastern Andean foothills. Mark and recapture samples were made during January to April 2006, covering both dry and wet seasons. We determined population size, daily survival probability, and longevity during the entire period and compared them with precipitation data. Age and sex…
Populations of Ischnura hastata found in the Azores archipelago represent the only known example of parthenogenesis in the order Odonata. In this paper, we present results from fieldwork done on the islands of São Miguel, Pico, Santa Maria, and Graciosa, aimed at characterizing population ecology and habitat preferences of this species. Sampling of several ponds…
In a large population of Lestes viridis inhabiting a complex, extended system of channels in the floodplain of the Upper Rhine River near Weisweil (Baden-Württemberg, Germany) detailed samples of exuviae were collected from several subpopulations. For each sample the sex ratio was determined. For statistical reasons only samples with at least 700 exuviae were considered.
The status of the odonate fauna of Europe is fairly well known, but the current IUCN Red List presents only six species out of ca 130, two of which are actually out of danger today. In this paper we propose a tentative list of 22 possibly declining or threatened species in the region. For the…
The Philippine odonate fauna is characterized by a high percentage of endemic species, especially in Zygoptera, most of which have a very limited range. Due to the continuing loss of forests and other habitat destruction, a majority of the 300 plus known species could be red-listed, but only a few critical species are evaluated here.