In September and October 1998 adults of Anax junius, (Common Green Darner) were encountered in small numbers at coastal sites in southwestern U.K. Circumstantial evidence supports the inference that they reached there on winds originating from New Brunswick and Quebec Canada in early September, a time when this species regularly migrates southwards along the Atlantic…
Geographical variation of prementum size in Iberian Cordulegaster boltonii (Odonata: Cordulegastridae) populations
Within wide geographical areas, Odonata populations can show biometric differences as a consequence of both biotic (e.g., predation, competition) and abiotic factors (mainly temperature). These differences can occur in the larval stage, although reliable characters are needed to detect differences.
Useful biometric variables in Iberian exuviae of Boyeria irene (Fonscolombe, 1838) (Odonata: Aeshnidae)
In species of similar shape and size, biometric analyses make it possible to establish differences. Within one species, biometrics can help researchers to detect differences between populations and analyze their adaptations to environmental conditions. Until now little was known about the biometrics of the Iberian populations of Boyeria irene (Odonata: Aeshnidae), a large species living mainly in southern Europe.
Flying activity and population dynamics of Cordulegaster heros Theischinger, 1979 (Insecta: Odonata: Cordulegastridae) in Slovakia
In 2017, we investigated the population dynamics and flying activity of the south-east European endemic dragonfly species Cordulegaster heros Theischinger, 1979. This research was conducted in the southern part of Central Slovakia in the Revúcka vrchovina Upland at a submountainous stream called Drienok. The mark-release-recapture method was applied to study the population. Cordulegaster heros was…
Wing shape patterns among urban, suburban, and rural populations of Ischnura elegans (Odonata: Coenagrionidae)
Dragonflies and damselflies (the Odonata) are among the most efficient flying insects. However, fragmentation of the landscape can increase distance between habitats and affect costs of dispersal, thus shaping phenotypic patterns of flight-related traits, such as wing shape, wing loading and wing size. Urban landscapes are highly fragmented, which limits dispersal among aquatic habitats. Hence,
Voltinism and larval population structure of Calopteryx splendens (Odonata: Calopterygidae) in the Po Valley
Adaptation of life-history traits is an important factor for the success of insects. Voltinism is a feature that descends from several life-history traits and, given that the latter depend on the specific environment of growth, voltinism can vary between populations across latitudes or habitats. In addition, some insects, like many odonates, have developed different patterns…
Genetic consequences of range expansions along several fronts in Crocothemis erythraea
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….
The Gomphidae of Algeria and the Maghreb: status, ecology and conservation (Insecta: Odonata)
A survey of the Gomphidae of Algeria and the Maghreb was carried out during the period 2013–2014. Sampling of eight main wadis across northern Algeria was undertaken and adults and exuviae were recorded. The survey yielded six species of Gomphidae. Among these, we report on the rediscovery of the Critically Endangered Lindenia tetraphylla in Algeria,…
Dorsolateral cuticular outgrowths in second stadium larvae of Gomphus flavipes (Odonata: Gomphidae)
Second and third stadium larvae of Gomphus flavipes have dorsolateral cuticular outgrowths in the form of small basal tubercles bearing fan-shaped setae. These sensilla are aligned in two rows on each side of the thorax and abdomen. European species of Gomphus, Onychogomphus and Ophiogomphus that we examined lack these structures, having instead, at most, short…
Sex ratio in Gomphidae (Odonata) at emergence: is there a relationship with water temperature?
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