In odonates, female specific color polymorphisms appear to be an evolutionary response to sexual harassment, but we know little about the decision rules males use when searching for variable females. For two sympatric species of Enallagma, we measured male responses to live female variants under field conditions, early and later in the day. In the…
Heteragrion makiritare sp. nov. is described from two males from the Pantepui region – holotype: Venezuela, Amazonas State, Marahuaka, Sima (3°43′N, 65°31′W), 1,140 m a.s.l., MIZA, no. 17250. It belongs in the species group whose paraprocts are absent in the male sex. The identity of H. macilentum is elucidated by examining its lectotype and a…
Progomphus obscurus is one of the most abundant dragonflies in South Carolina, USA. We collected dragonfly larvae from 127 sites in the Enoree River and nine of its tributaries, and correlated the abundance of P. obscurus larvae with physical and chemical characteristics of these streams. As expected for this burrowing species, larval abundance varied among…
The article considers the phenomenon of ballistic defaecation by odonate larvae, exhibited by certain Anisoptera but not by any Zygoptera, and explores two possibilities: (1) that ballistic defaecation in Anisoptera may correlate with increased foraging success (the ‘Wudkevich Hypothesis’) by distancing the prey’s alarm pheromone, persisting in the pellet after defaecation, from the larva’s ambush…
Thirty-five dragonfly species are reported from Mongolia and Inner Mongolia. Three are first records. A non-parametric test is used to determine the total number of species to be expected. It suggests that the current number of 62 may be asymptotically complete, except for some specific zones like the Bulgan valley in the south-west, and the…
Communities have a nested-subset structure if the species found in species-poor assemblages are also found in progressively more species-rich assemblages. This nested-subset structure can be caused by differential colonization rates among species, differential extinction rates among species, or nested niche space. In this study, the assemblages of larval odonates in the Enoree River of South…
A collection of 448 Odonata specimens made on Pohnpei, Caroline Islands, Micronesia, in 2001–2002 allows a reassessment of the fauna of this small, isolated island. There are 15 species, including six species of the zygopteran genus Teinobasis, which apparently speciated in situ, an unusually great diversity for such a small island. One of these species…
The larva of Megaloprepus caerulatus is described and illustrated from specimens collected near the northern border of Barbilla National Park on the Costa Rican Caribbean slope. Habits and characters of larvae of three different size classes obtained from artificial tree holes permit the identification of small (body length 4 mm, excluding the caudal lamellae) larvae…
Amanipodagrion gilliesi was known previously only from four males collected in 1959 and 1962 in the Usambara Mountains, south-east Tanzania. Recently it has been rediscovered at two shady streams in that area. The species is not living in swamps, as previously stated, but is apparently restricted to a small area in the Amani-Sigi Forest. Data…
Site attachment and displacement of adult Somatochlora alpestris were studied by means of mark-release-resighting during two years at two clusters of ponds (A, B) ca 8 km distant from each other on opposite slopes of Prättigau Valley in the Swiss Alps. Data on 127 marked tenerals in 1998 and 92 in 2000 at (A) were…