In the temperate zone, male perch height of co-occurring dragonfly species (Odonata: Libellulidae) often correlates with species body size. I tested for this relationship in a guild of tropical dragonflies at a wetland at La Selva Biological Station, Heredia, Costa Rica. Males of 12 species were observed perching in January–February 2016. Mean male perch height…
Phenotypic plasticity represents an adaptive tool in organisms including odonates to cope with heterogeneous environmental conditions. However, while some odonate species can occupy various changing habitats, other species are adapted to a narrow range of environmental conditions. Commonly, behavioural modifications are applied to avoid detection and encounters with predators. But reduced behavioural activity results in…
Little is known about the ability of adult dragonfly individuals to survive into or over the winter in the Cape Floristic Region (CFR), a significant biodiversity hotspot in South Africa. Dragonfly species richness and abundance were recorded throughout winter and into spring in Jonkershoek Nature Reserve. Several environmental variables were also measured. Individuals of eight…
Behaviour of dragonflies was observed during the partial solar eclipse in Saitama, Japan, on 22 July 2009. The solar eclipse started at 09:54 h, reached its maximum magnitude of 74.9% at 11:12 h, and ended at 12:29 h. Light intensity at the peak of the eclipse was 1005 lx, a reduction by 28.2% of that…
The reproductive behaviour of Libellago semiopaca was studied on a swift-flowing shallow forest stream in Brunei. Females oviposited just below the water-line, commonly in groups, only on large, firm-textured, semi-submerged logs, usually guarded by males. Both sexes were very sedentary. Suitable sites, with good illumination and deep deposits of fine gravel and leaf mulch in…
We revisit the hypothesis, first advanced in 1962, that, with regard to their means of thermoregulation and overt behaviour, two types of Odonata can be recognised: fliers, when active (during reproductive activity, primarily, or foraging) remain on the wing, whereas perchers, when similarly engaged, spend most of the time on a perch from which they…
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…
The region covered is briefly defined and characterized as relatively little disturbed. A survey of relevant odonatological literature, including local Red Lists, is given, along with current scientific activity. Sixteen species are indicated, which deserve special attention, one of them, Ischnura aralensis, being the only strict endemic in the region. Some isolated populations deserving protection…
Japan is a small country but ranges from the subtropical to the subarctic zone. Every year during spring to autumn, many typhoons bring tropical taxa, which occasionally establish in Japan. Up to now, 215 odonate taxa have been recorded, 34 of which are regarded as critical species. Intensive research on Odonata – supported by identification…
Pseudagrion lalakense, a new species of coenagrionid from Borneo, is described and figured. The species is phylogenetically close to the very widespread and eurytopic P. microcephalum and the two fly together. P. lalakense may be distinguished from microcephalum and several other similar blue species by the pattern on the thorax and abdomen in both sexes…