Global warming has altered the ranges of many species, especially those of insects and other ectotherms that are particularly susceptible to rising temperatures. Four decades ago, the dragonfly Crocothemis erythraea began to demonstrate northern range expansion in Germany, as well as in Belgium, the Netherlands, Poland and the UK. The rapid range expansion of C….
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
Our understanding of mating systems is highly skewed toward temperate examples. This study investigated the mating system, sexual size dimorphism and seasonal variation in local distribution and abundance of male and female Telebasis carmesina, a common damselfly in Brazilian tropical savanna. In a natural reserve, daily census and behavioral observations were made throughout 1 year…
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…
Size and mass are often uniformly related within individuals and populations, but the relationship may vary in time or space. I asked whether isolated adult dragonfly populations within the same environmental context (climate, physiography, ecoregion) differ in both size and mature mass, and whether earlier emerging dragonflies are both larger and heavier on average. Differences…
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…
We compiled data on the occurrence and frequency of distinct female variants among Holarctic Odonata and interpreted the data in light of harassment-based hypotheses. The major source of male confusion for male mimicry hypotheses is predicted to be signal similarity between andromorphs and male distractors; for the learned mate recognition hypothesis (LMR), it is predicted…
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 status of the odonate fauna of Europe is fairly well known, but the current IUCN Red List presents only six species out of ca 130, two of which are actually out of danger today. In this paper we propose a tentative list of 22 possibly declining or threatened species in the region. For the…
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…