The diversity of odonates was analyzed along an elevation gradient from 100 to 2 450 m of the San Marcos River within the states of Hidalgo and Puebla, Mexico, through systematic collections from July to October 2019, and March to June 2020. Adult individuals belonging to nine families, 38 genera, and 87 species were recorded. The completeness of the inventory was obtained with the estimator bootstrap and ranged between 90 and 93 %. The elevational pattern observed was an increase in species richness and diversity with decreasing elevation. Beta diversity was 81 %, replacement 47 %, and nestedness 33 %. The highest beta diversity was found when comparing the site located at the highest elevation to the other four sites and the lowest diversity values were found between medium and low elevation sites.

The Odonata fauna of three different artificial habitats in the Seville urban area, southern Spain, was analysed and compared: a channel with concrete walls, two ponds located inside a public park, and the old watercourse of the Guadalquivir River, a dead arm lacking water flow. Invasive animal species were common at these sites. No restoration or conservation measures or management practices to facilitate the development of autochthonous fauna have been undertaken. Ischnura graellsii, Anax parthenope, Crocothemis erythraea, and Trithemis annulata were observed repeatedly and consistently. Other frequent species were Sympetrum fonscolombii and Trithemis kirbyi. Odonata diversity of the four urban water bodies was poor and the spectrum of species trivialised. More than 90 % of the Anisoptera records pertain to thermophilic species with a wide African distribution. Only one European endemic, Platycnemis latipes, was found. Several species exhibited multivoltine life cycles in these artificial habitats.

An updated check-list of 69 species of Odonata occurring in the territory of the Republic of Belarus is presented in tabular form, indicating the presence of each species on the level of administrative regions (voblasc'). The data set for the check-list was created by compiling original data, records retrievable from available publications and databases, and those from museum collections. Contrary to current literature, due to a lack of reliable records, four Odonata species previously claimed for Belarus are not considered as being part of the Belarusian fauna, viz. Coenagrion ornatum, C. scitulum, Aeshna caerulea, and Somatochlora alpestris. Hitherto known records of Aeshna soneharai, a recently described new member of the European dragonfly fauna, are outlined. The history of discovery of rare species is critically reviewed. The flight period of each species is given in tabular form.

An annotated check-list of Odonata species occurring in the Republic of Moldova is presented. The check-list is based on an evaluation of literature published from 1903 onwards and the authors' own collections between 2013 and 2023, based on research conducted on Odonata larvae and adults. In total, 46 species records are currently considered credible and are included in the check-list. Eight additional species are considered as potentially occurring in Moldova, but at present lack any reliable record, and six species implausibly recorded have been rejected. Chalcolestes parvidens and Sympetrum fonscolombii are recorded for the first time for Moldova.

We describe the immature and mature morphs of Ischnura saharensis, based on individuals from Gran Canaria (Canary Islands, Spain), and report population morph frequencies for this species from Gran Canaria and Morocco, and for I. genei from the Mediterranean islands of Sardinia and Sicily. We found that I. saharensis has a wide range of colour variation in females, resulting from the combination of three colour morphs with ontogenetic colour changes. Mature androchrome females have a bright green thorax, very similar to males, but some are bluer than males when immature. Gynochrome females are either greenish-brown when mature (infuscans morph) or ochre-brown (aurantiaca morph). Ischnura saharensis from Morocco showed a preponderance of androchromes in one population and aurantiaca in the remaining three. The infuscans morph was the rarest. In contrast, androchromes were slightly more frequent than the other morphs (34–40 %) in Gran Canaria, and the proportion of infuscans and aurantiaca was very similar (30–34 %). In the case of I. genei, the aurantiaca morph was the most common in all populations (58–77 %). No infuscans females were found in Sicily, but these represented 8–23 % of females in Sardinia. Even when the infuscans morph was the rarest in I. saharensis, this morph was in all cases over-represented among mating pairs (significantly in one population). In I. genei, the aurantiaca morph was the commonest and the most frequently found mating (significantly in one population). Our results suggest that I. saharensis and I. genei resemble I. elegans in their wide variation of population frequencies between regions, supported by the fact that androchrome females mate at low frequencies.

Visits by Anax imperator to breeding ponds were recorded in north-western Germany from dawn to dusk. On warm and windless sunny days, the species flew in three clearly defined time periods: before sunrise, from morning to afternoon, and from sunset to nightfall. Feeding flight over the water was only observed during both twilight periods, with both sexes foraging. Males patrolled not only in the diurnal period, but also at dusk and occasionally at dawn. Females oviposited during the diurnal period and on average flew one hour later than the males. The latest-flying vespertine males cruised close to the water surface during the last minutes of daylight, losing their aggression towards other males and finally leaving the pond when minimum light intensity reached 4 lx. Our observations confirm that mating is not initiated at the breeding ponds, although patrolling males and egg-laying females encounter each other there for hours during the diurnal period. The rendezvous site of the species is obviously away from the water. Overall, given its general abundance there are relatively very few records of mating wheels, which is why we assume that females mate rarely, perhaps even only once in their lifetime. Thus, the purpose of the long-lasting patrol flight remains a mystery.

This study investigates the reproductive habitat of Sympecma paedisca at Lake Constance, a region of special importance for the conservation of the species in Germany, focussing on vegetational characteristics. The reproductive activity of S. paedisca was analysed by sampling active individuals along transects, distinguishing between males, females, and tandems. Sixty-eight plots, including controls, were defined according to the S. paedisca observations, and vegetation surveys were conducted on each plot. Additionally, an analysis of the relationship between long-term S. paedisca monitoring data and the expanse of flooded reedbeds and reed meadows (i.e., traditional litter meadows used to produce bedding for the stables) was conducted. The results suggest that the reproductive habitat description for S. paedisca at Lake Constance needs to be revised. The importance of sparse P. australis vegetation for S. paedisca was highlighted and the plant community of low sedge swamps was identified as additional reproductive habitat. Overall, the results indicate that plant community composition is not the main cue for S. paedisca habitat selection. Whilst the reed meadows are significant reproductive habitats for S. paedisca, this is not the case for the reedbeds.

A late instar larva of an unknown calopterygid species, here termed ‘species Q’, was collected at Godawari, Nepal, in 1992 by SGB. It resembles, but appears to differ fundamentally from a larva described erroneously as Caliphaea confusa by F.C. Fraser from Meghalaya, Assam, in 1943. Fraser’s description seems to contain impossible discrepancies but the original specimen may pertain to Echo margarita, which occurs in the same locality. However, there are no records of this genus from Nepal, from where just three species of the family, Caliphaea confusa, Neurobasis chinensis and Vestalis gracilis, are known. None of these three genera have larvae matching that of ‘species Q’. The mystery larva is described and compared with that described by Fraser. Fraser’s description is analysed and critiqued. The larva is concluded to be related to the genera Mnais, Echo and Psolodesmus but its specific identity and that of the larva described by Fraser remain uncertain, with the possibility of ‘species Q’ representing a new species or even a new genus with an unknown adult being suggested.

The final instar larva of the large, spectacular Philippine and Luzon endemic euphaeid damselfly Heterophaea barbata (Martin, 1902) is described and illustrated for the first time, based on field collected exuviae of both sexes. Identification is by supposition, but larvae of the only other euphaeid on the island, Euphaea refulgens Hagen in Selys 1853, have been previously described and illustrated and can be confidently ruled out. The specimens are exceptionally large for the family and present several novel structural features not recorded in other euphaeid genera. The antennae of the principal specimen studied were asymmetric in length and numbers of segments, suggestive of a possible teratological event caused by genetic load or environmental factors during development. This and other specimens exhibited up to 14 antennomeres, more than hitherto recorded for any odonate larvae.

The name-bearing types of Zygoptera preserved at the Senckenberg-Museum Frankfurt/Main (SMF), Germany are catalogued. There are 464 name-bearing types of 104 taxa deposited at the SMF. Of these taxa there are 68 additional paratypes and paralectotypes. The holotype male of Disparocypha biedermanni and both syntypes of Acanthagrion lindneri are missing. The type status of Chalcopteryx radians, Cora irene, C. notoxantha, Euthore leroii, Bayadera melanopteryx, Calopteryx melli, Vestalis smaragdina velata, Platycnemis agrioides, Acanthagrion adustum, A. kennedii, Enallagma fractum, and Pseudagrion pontogenes is investigated. All types of these taxa are considered syntypes, because their lectotype designations were invalid. In addition, 222 secondary types of 69 other taxa are listed. A supplementary list of name-bearing types of Zygoptera of 39 taxa described by Friedrich Ris and deposited in collections other than the SMF is provided. Evidence that Aciagrion feuerborni is a junior synonym of A. approximans is discussed.