Clutch size is an important fitness component often quantified artificially by inducing oviposition in libellulid females. Female behavior and egg production of the yellow-veined skimmer, Orthetrum nitidinerve, were studied in northeast Algeria during its reproductive season. Data on reproductive behavior and biology of this Mediterranean endemic species has not been published previously. Males guarded territories…
Oviposition behaviour by Sympetrum frequens, a species endemic to Japan, has been observed throughout its entire breeding season, which extended for about one month after the harvest of rice. Approximately 50% of oviposition events occurred during the first week of the reproduction period. Sunny oviposition sites were preferentially selected by ovipositing pairs. The starting time…
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…
Monitoring methods always recommend gathering data during the maximal activity of adults. Hence monitoring the threatened Lestes macrostigma requires knowledge of its activity pattern. Dragonfly “activity” is ambiguous and its intensity can be assessed in different ways, including by the threshold of response to a predator stimulus, i.e. “awareness”. We studied the daily pattern of…
It is expected that climate change will have a great impact on many species and habitats. This will be greater if populations are found at the edge of their range or are isolated, and could lead to regional extinction. Here we investigate the possible impact on two boreo-alpine dragonfly species, Somatochlora alpestris and S. arctica,…
Due to the destruction of its primary habitats, the West Palaearctic libellulid Orthetrum coerulescens has suffered much decline in central Europe. However, at the regional scale it has survived in a variety of secondary habitat, such as draining ditches. In order to find adequate measures for its conservation and promotion, habitat use and habitat recognition…
Of the many Zygopteran genera that occur in the Neotropics, only five (Hetaerina, Archilestes, Lestes, Argia, and Ischnura) are represented north of 40°N in North America, and only three of these (Hetaerina, Archilestes, and Argia) probably had a tropical origin. In the two genera of Lestidae (Archilestes and Lestes) the life history of temperate-zone populations…
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…
Climate change brings with it unprecedented rates of increase in environmental temperature, which will have major consequences for the earth’s flora and fauna. The Odonata represent a taxon that has many strong links to this abiotic factor due to its tropical evolutionary history and adaptations to temperate climates. Temperature is known to affect odonate physiology…
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.