Melanic individuals in color polymorphic Enallagma damselflies result from phenotypic, not genetic, variation

Genetically determined color polymorphisms have a long history in the study of evolutionary change acting on populations. The Odonata exhibit relatively high levels of sex-specific color polymorphisms in mature adults. In Ischnura and Coenagrion, female-specific polymorphisms are known to be controlled by Mendelian genes. Nearly half of Enallagma species have polymorphic females, but the inheritance…

Slow-motion analysis of female refusal behaviour in dragonflies

By means of slow-motion film analysis we found new female refusal behaviour patterns against male harassment in a variety of Odonata species. Often, females could escape simply by flying faster than males. Due to the morphological preconditions, there were differences in the two suborders. In Anisoptera, several behavioural specialities were analysed: (a) females of Aeshna…

A preliminary study on female-limited colour polymorphism in Lestes sponsa

Female-limited colour polymorphisms are widespread in Odonata, usually showing an androchrome and one or more gynochromes. Androchromes have been hypothesized to function as male mimics with a consequent decrease of male harassment, although males may also learn to recognize the different female colour morphs. In the Eurasian damselfly Lestes sponsa, the occurrence of two female…

Variation in fluctuating asymmetry among nine damselfly species

Fluctuating asymmetry (FA), measured as random deviations from bilateral symmetry, likely results from developmental disturbances by internal or environmental stresses. However, comparisons of FA in single damselfly species (Odonata: suborder Zygoptera) from stressed environments have often been inconclusive. We measured levels of FA among multiple species of damselflies from the same environment to determine the…

Aerial dispersal of freshwater gastropods by dragonflies (Odonata)

At a ditch near Tribsees in northeastern Germany a young individual of the freshwater snail Lymnaea stagnalis was photographed while attached to the dorsum of the abdomen of a female Aeshna viridis, after the odonate took off after oviposition in Stratiotes aloides. This is the first known case for odonate-born dispersal of freshwater gastropods.

Odonata of Tuva, Russia

The odonate fauna of Tuva in Siberia, Russia, is documented, based mainly on data from expeditions in 1990, 2000 and 2004, and examination of collections preserved in Novosibirsk. The checklist of Tuvinian Odonata presently includes 47 species. In the southern Ubsu-Nur depression 29 species were recorded (two just there); in the Central Tuvinian depression 34…

The larva of Podolestes orientalis from West Malaysia, with notes on its habitat and biology (Odonata: Megapodagrionidae)

The larva of the south-east Asian megapodagrionid, Podolestes orientalis, is described and figured. Specimens were collected from shallow forest pools lined with large dead leaves in secondary lowland forest. Final and earlier stadium larvae were found concentrated around the edges of pools in very shallow water. Larvae sometimes perched in exposed situations, just below the…