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.
As warm-adapted insects of tropical origin, Odonata cope with cold periods by seasonal regulation and diapause. A model for larval-overwintering species is proposed with three response patterns related to the timing of emergence, which can be predicted from seasonal cues during the last few stadia. For emergence during the present season, there is an often time constrained pre-emergence development, accelerated by long days and higher temperatures.
The department of Ñeembucú, in south-western Paraguay, is home to the virtually unexplored Ñeembucú Wetlands, the second largest wetland system in the country, representing a major gap in biodiversity knowledge. As organisms ubiquitous with wetlands, the Odonata, or dragonflies (Anisoptera) and damselflies (Zygoptera), have the potential to be effective indicators of wetland habitats in the…
Water mites (Arrenurus spp.) parasitize adult dragonflies. We collected dragonflies weekly at 11 waterbodies in Greenville Co. and Pickens Co., SC, USA, to: (1) compare parasitism prevalence across species, sites, and sampling periods; (2) test the hypothesis that prevalence correlates with host abundance; (3) test the hypothesis that prevalence is inversely related to host diversity…
The final larval stadium of four species of Cora are described and compared with known species in the genus. Cora skinneri Calvert, 1907, C. semiopaca Selys, 1878 and C. lugubris Navás, 1934 are described and illustrated for the first time using material from Costa Rica for the first two and from Colombia for the latter….
Females of Forcipomyia paludis were studied microscopically during their feeding action on Odonata wings where they were mostly attached to main veins in the basal half of the wings. In some individuals rhythmic nodding of the head was noted. Conspicuously many midges lifted the abdominal tip every one or two minutes and from the anus…
A comparison of the description of Brachythemis liberiensis with material of B. leucosticta and Parazyxomma flavicans has shown that B. liberiensis is a synonym of P. flavicans. B. liberiensis should be removed from the list of threatened African Odonata. The relationships between the genus Brachythemis and the Zyxommatini are briefly discussed. Further arguments for a…
Oviposition of Sympecma paedisca was observed in eastern Kazakstan. The main oviposition substrates were living Phragmites leaves. In comparison with European and Japanese populations we propose geographic variation in the proportional use of horizontal versus vertical oviposition substrates. Ovipositing females seemed to avoid the inner parts of Phragmites stands and there was a preference for…
In the dragonfly Anax nigrofasciatus nigrofasciatus (Aeshnidae, Anisoptera), the X-tissue is the tissue which occupies the posterior corner of the larval eye and which forms the large facet region in the dorsal part of the adult compound eye after emergence. In the early period of the last larval instar, an ommatidial retinula of the X-tissue…
Globally, freshwater ecosystems and the organisms that depend on them are at risk. Dragonflies and damselflies (collectively, “odonates”) have a history of being used as bioindicators of freshwater habitat quality due to their wide range in environmental sensitivities across species and because they are relatively accessible.