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…
In a heterogeneous environment, males of Somatochlora flavomaculata regularly occupy site-fixed locations away from water, adjacent to vertical landscape elements, and to a lesser extent, also at water, i.e. at oviposition sites. Territories both over land and over water are typically patrolled by continuous site-fixed flights. These places serve as rendezvous sites where copulation is…
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 reproductive behaviour of Neurobasis kaupi was studied for the first time in Central and South Sulawesi. The species was recorded in a wide variety of clear and fast flowing creeks, streams and rivers, mostly in forested areas. The males were territorial and defended potential oviposition sites, a limited resource. Territory owners demonstrated their presence…
Sympetrum vicinum is a sit and wait predator, which takes off and pursues small flying insects during its long flying season (July to November). We investigated whether foraging individuals become less discriminating regarding prey size selection during the fall season because the changeable fall weather has an impact on the prey population. To investigate the…
Zygoptera show two perching modes, one with wings closed and one with wings open. These perching modes are distributed unequally through the suborder; most Zygoptera perch with closed wings, but species in 43 genera of eight families at least occasionally – in most cases usually – perch with open wings. Alternative hypotheses to explain this…
The mark-and-recapture method was used to study the population dynamics of the endangered brackish water species, Mortonagrion hirosei, in a small reed community of an estuary in the warm-temperate zone of Japan. The flying season was from late May to early August. The age structure showed that newly emerged adults always stayed in the reed…
The functional morphology of the male caudal clasping apparatus of Zygoptera is compared to that of Epiophlebia superstes (Anisozygoptera) and Anisoptera. Hypotheses concerning the mechanics and muscle functions have been advanced by parallel construction of mechanical working models. The evolution of the clasping apparatus and the tandem linkage shifting – from the female pronotum to…
Site attachment and displacement of adult Somatochlora alpestris were studied by means of mark-release-resighting during two years at two clusters of ponds (A, B) ca 8 km distant from each other on opposite slopes of Prättigau Valley in the Swiss Alps. Data on 127 marked tenerals in 1998 and 92 in 2000 at (A) were…
A brief Odonata survey in southern Florida, USA, in January 2000 resulted in the discovery of two new species, Chrysobasis lucifer and Nehalennia minuta, for the USA and established populations of two other species, Tholymis citrina and Tramea calverti, that had been considered vagrants. Flight seasons of six additional species were extended. These records are…