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We present the first comprehensive inventory of the Odonata of the Chapada dos Guimarães National Park, Mato Grosso state, Brazil, established in 1989. In total, we collected 576 specimens from 94 species, 42 genera and nine families, with 25 species representing records new to Mato Grosso state. At least 285 Odonata species are now recorded from the state. Our results highlight the importance of protected areas for species conservation and suggest that additional collections inside and outside the National Park may increase the number of recorded species in that region.
Aeshna cyanea is a new addition to the fauna of Fuerteventura, Canary Islands. In this study the circumstances surrounding the discovery of an emerging female, with exuvia collected, in a permanent pool in arid environment, in the Barranco de Rio Cabras, are described. The breeding record, syntopy with typical desert species (e.g., Orthetrum ransonnetii) and potential explanations for this unusual occurrence are discussed.
While Anisoptera are more commonly associated with long-distance dispersal, there are notable cases of Zygoptera colonising remote areas such as desert oases and oceanic islands. Despite being generally regarded as less mobile, many Zygoptera species have demonstrated substantial dispersal ability, challenging previous assumptions. However, these findings have had limited impact on the prevailing consensus. Current understanding of species mobility relies heavily on capture-mark-recapture (CMR) studies, which sometimes conflict with direct evidence of species expansion or with the results of molecular analyses. Although tracking species by tagging can provide valuable information, it appears to underestimate long-distance dispersal, and therefore general conclusions should be treated with caution. This paper provides an overview of documented instances of long-distance dispersal in Zygoptera, covering cases ranging from migration events to the expansion of species' ranges and concluding with pioneer species with dispersal incorporated into their life strategy. Additionally, the problems caused by treating Zygoptera as sedentary for odonatological research and species conservation policy are discussed.
Late October 2023 saw an influx of the migratory Nearctic Anax junius into both the Isles of Scilly in south-western Britain and the Île d'Ouessant in north-western France, with at least eleven dragonflies being reported and with further sightings likely to involve additional individuals. This species has only been observed in the Western Palaearctic since 1998, and all known records from the region are documented and discussed; such records are currently restricted to the autumn months, and come predominantly from south-western Britain and western France, with at least one sighting also on the Azores. Meteorological conditions preceding arrivals have been dominated at mid latitudes by mobile westerly airflows across the entire Atlantic, and it is thought the dragonflies arrive in Europe via wind-assisted non-stop flights directly across the ocean, with a likely journey time of approximately four days.
Forest diseases caused by fungi, such as Elm graphiosis and Alder phytophthora, have become a serious problem in the conservation of riparian woodland. Freshwater habitats in the Mediterranean are under diverse anthropogenic pressures; of these, the forest management in the surroundings is among the least analysed. Odonata larvae in a permanent stream in the Sierra Morena were studied for twenty-seven years, recording the changes that occurred in the stream bed and the surrounding forest. Several diversity indices were analysed and apparent differences between years in Odonata species richness were recorded. Our findings show that forest diseases, as a consequence of anthropogenic activities, can initially lead to a higher Odonata diversity in Mediterranean permanent streams. This increase in species richness is a consequence of an increase in the seasonality of the flow and luminosity in the channel from late spring to early autumn. Homogeneity of the stream bed due to the disappearance of alternate riffles and ponds of more than a meter deep, and the appearance of strongly rooted aquatic phanerogams like water-cress also plays an important role. The populations of Anisoptera species with a long life cycle, which previously were the only ones inhabiting the stream and which still are dominant today, will possibly disappear in the long term.
Libellulidae generally adopt a promiscuous reproductive strategy. Males and females mate several times and with several partners during their lives. The males attempt to copulate with as many females as possible, encourage them to lay eggs in their territories and deny rivals access to their females. On the other hand, the females seek to lay as many eggs as possible with good paternal genes in optimal habitats. The behaviour exhibited by both sexes appears to maximise lifetime reproductive success. In this study, we investigated the mating and guarding behaviour of Libellula quadrimaculata in small bog ponds. We focused on repeated extrapair and especially intrapair copulations at a given site as well as non-contact guarding when there was little interference by rival males. It was noticed that females were pursued by their partner after egg laying and when attempting to leave the water. Either they mated again, or the male tried to steer his partner back to the water. Two to six additional matings between oviposition bouts occurred during each encounter. A total of 54 intrapair copulations with subsequent oviposition were recorded. Attempts by a male to guide his mate back to his territory and encourage her to continue laying eggs were successful in 33 cases, while in 64 cases the female escaped. Thus, repeated copulations and retrievals are tactics used by a male to maximise laying of eggs he has fertilised by the female with whom he last mated. The costs and benefits of this behaviour are discussed from the perspective of both males and females.
We investigated communal nocturnal roosting aggregations of Cratilla lineata in the Chia-Ling Lake area in Tainan, Taiwan. Communal roosting began during the colder months from late October to mid-March. The dragonflies roosted 2–4 m above the ground on slender vines such as Bauhinia championii, Dalbergia benthamii, Hiptage benghalensis, and Pothos chinensis, under open canopies along a forest path. The aggregations exhibited a sex ratio predominantly skewed towards males and their numbers were negatively correlated with daily mean temperature, indicating that more dragonflies roost as temperatures decrease. The dragonflies showed fidelity to specific roosts and vines. Roosting began between 15:30 h and 17:00 h CST (UTC+8) when light intensity was high (252–3 607 lux). They departed between 08:50 h and 12:00 h, 2–6 hours after sunrise, with light levels ranging from 1 103 to 9 567 lux. The mechanisms and adaptive value of this behaviour remain open to speculation.
This study describes and illustrates for the first time the final larval instar of Ischnura saharensis Aguesse, 1958, based on the analysis of 26 F-0 larvae and 29 exuviae gathered on Gran Canaria and Fuerteventura, Canary Islands, where it is the only species of damselfly present. We examine 16 morphometric traits and analyse the biometric and morphological differences between the females and males. Lastly, we compare the information obtained with corresponding knowledge of sympatric congeneric species distributed throughout the Iberian Peninsula and the Maghreb. Ischnura saharensis can be distinguished from other species by the structure of the genitalia, caudal lamellae, and cerci.
A new species of Malgassophlebia Fraser, 1956 (M. baaka sp. nov.) is described from the Nouabalé-Ndoki National Park, Republic of Congo, based on a single male adult. Diagnostic features and the type locality of the new species are illustrated.
In 1889, Filip Trybom described Somatochlora sahlbergi, based on three male syntypes and one female syntype, and S. theeli, based on two female syntypes, collected on the Swedish expedition to the Yenisey River in 1876. In 1931, K.J. Valle discovered that the type series of S. sahlbergi was heterogeneous since the female syntype was in fact another species, S. alpestris. At the same time, the two female syntypes of S. theeli appeared conspecific with the male syntypes of S. sahlbergi. Acting as the First Reviser, Valle chose the name S. sahlbergi as valid for the species which was actually new to science, but there remained a formal uncertainty of its sense because of the heterogeneity of the type series. In order to formally justify the use of the established name S. sahlbergi for this species, we have designated a male syntype specimen, collected at Dudinskoe village (presently the town of Dudinka) on 30.vii.1876, as the lectotype of S. sahlbergi.
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