The status of the Odonata as a model taxon for studying the evolution and diversity of reproductive behaviours is shown here to have declined relative to crickets and Drosophila. Very few available data on ejaculate size, the number of sperm stored by females and the duration of sperm storage reveal poor knowledge of these areas…
The taxonomy of the Gynacantha and Heliaeschna species from continental Africa is problematic, and available keys are unsatisfactory. ‘Traditional’ characters such as venation and ‘innovative’ ones like abdominal denticulation are evaluated and their variability is measured and discussed. G. quadrina is a synonym of G. africana and not of G. vesiculata, G. ochraceipes is regarded…
Co-occurring odonate species often perch at different heights. We studied the effects of interspecific and intraspecific interactions on perch-height selection by Perithemis tenera, Pachydiplax longipennis, and Enallagma spp. by creating artificial perch stations and comparing perch selection when species perched alone or together. We also compared the frequency of perch-height use in the presence or…
Zygoptera show two perching modes, one with wings closed and one with wings open. These perching modes are distributed unequally through the suborder; most Zygoptera perch with closed wings, but species in 43 genera of eight families at least occasionally – in most cases usually – perch with open wings. Alternative hypotheses to explain this…
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…
Orthemis sibylla is shown to be a junior synonym of O. ambirufa, based on a comparison of the holotype male of O. ambirufa with voucher specimens in the UMMZ identified as O. sibylla by Ris and specimens of this species from French Guiana and Venezuela in the RWG collection. Diagnostic characters of the male holotype…
This report summarizes progress that has been made during the past five years toward the understanding of Neotropical Odonata. It also presents a list of critical species and sites, threats to Odonata conservation in the region, and priorities for further research. This region, the richest in the world for Odonata, must be a focus of…
Of the approximately 439 species of Odonata known from North America, north of Mexico, comments on 25 species (6%) of conservation concern are given. Species deemed to be under the most threat are Ischnura gemina, Gomphus sandrius, Ophiogompbus australis, Stylurus potulentus, and Libellula jesseana. Two other species not under threat, Neurocordulia micbaeli and Somatochlora brevicincta,…
Ten species of Hawaiian Odonata are considered to be currently at risk, all of them zygopterans belonging to the endemic genus Megalagrion. These species and their proposed status are as follows: M. jugorum, endemic to Maui and Lanai [CR, possibly EX]; M. leptodemas, endemic to Oahu [CR]; M. molokaiense, endemic to Molokai [CE, possibly EX];…
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…