The larva of Cordulegaster vanbrinkae Lohmann, 1993 is described and illustrated based on fourteen final instar larvae and 49 exuviae that were collected in Gīlān, Māzandarān and Golestān provinces, in northern Iran in July 2014, July 2017 and August 2018.
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.
Emergence substrate and sunlight penetration inherently trade off in patchy vegetation. Given the importance of solar radiation at emergence, we expected greater sunlight availability in sparse vegetation to advance emergence timing and reduce the average height of emergence fixation. We used outdoor mesocosms stocked with varying cattail (Typha) densities and late-stage Pachydiplax longipennis (Odonata: Libellulidae)…
The transition between larval and adult stage in amphibious insects is called emergence. During emergence abdominal contractions and excretion of liquid drops can be observed in several insect orders. Since the function of these processes is not yet known in odonates, this study examines the probable function of abdominal contractions and excretion of liquid drops…
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
Two distinct emergence styles have been reported in odonates, with both the upright and hanging back emergence reported in the Petaluridae, between and within individual species, including Petalura gigantea. This paper reports three additional observations of upright emergence in P. gigantea, providing further evidence that this emergence style is the norm for the species.
Emergence studies in Odonata provide information on the behaviour, ecology and fundamental demographic parameters in population studies. This paper reports on a study of sex ratio at emergence, pattern and duration of the emergence season, and potential cohort splitting in Petalura gigantea. Sex ratio at emergence varied among years, habitat patches and swamp types. Across
Anisoptera emergence in the seasonal tropics was monitored at a 35-ha managed wetland site in Hong Kong from February 2004 to November 2007. Exuviae records of 18 species from multiple emergence screens, exuviae traps and transect surveys were combined. The presence of adults during this period was also monitored. The study site comprised a mosaic…
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 behaviour of Anisoptera during the period between emergence and the onset of sexual activity is poorly known, mainly because freshly emerged adults are hard to follow. In the present study the system RECCO® Transmitter/Receiver and custombuilt tags made from Schottky diodes and copper wire were used to monitor freshly emerged Anisoptera. The system had…