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In Europe, a cosmopolitan dragonfly species Pantala flavescens is scarce. Along the Adriatic coast, only two records, from Montenegro in 1972 and from Croatia in 2010, have been known so far. On 30. 7. 2025, a female of the species was observed in the canteen of Božava Hotel on the island Dugi otok in Dalmatia. This represents only the second record of the species for Croatia. V Evropi je kozmopolitska vrsta kačjega pastirja Pantala flavescens na splošno zelo redka. Z območja ob jadranski obali sta bila doslej znana le dva podatka, iz Črne gore leta 1972 in iz Hrvaške leta 2010. Dne 30. 7. 2025 je bila samica te vrste opažena v jedilnici hotela Božava na Dugem otoku v Dalmaciji, kar je šele drugi podatek za vrsto na Hrvaškem.

Significance Human color vision is tri-chromatic, with three opsins expressed in cone photoreceptors that are sensitive in the red, green, and blue region of the spectrum. As theories predict, such tri- or tetra-chromacy with three or four opsin genes is common among mammals, birds, and other animals, including insects. However, we discovered that dragonflies possess as many as 15–33 opsin genes that have evolved through dynamic gene multiplications and losses within the lineage of dragonflies. These opsin genes are differentially expressed between adult and larva, as well as between dorsal and ventral regions of adult compound eyes, which plausibly underpin the versatile behavioral and ecological adaptations of actively flying adults to aerial lifestyle and sedentary larvae to aquatic lifestyle. Dragonflies are colorful and large-eyed animals strongly dependent on color vision. Here we report an extraordinary large number of opsin genes in dragonflies and their characteristic spatiotemporal expression patterns. Exhaustive transcriptomic and genomic surveys of three dragonflies of the family Libellulidae consistently identified 20 opsin genes, consisting of 4 nonvisual opsin genes and 16 visual opsin genes of 1 UV, 5 short-wavelength (SW), and 10 long-wavelength (LW) type. Comprehensive transcriptomic survey of the other dragonflies representing an additional 10 families also identified as many as 15–33 opsin genes. Molecular phylogenetic analysis revealed dynamic multiplications and losses of the opsin genes in the course of evolution. In contrast to many SW and LW genes expressed in adults, only one SW gene and several LW genes were expressed in larvae, reflecting less visual dependence and LW-skewed light conditions for their lifestyle under water. In this context, notably, the sand-burrowing or pit-dwelling species tended to lack SW gene expression in larvae. In adult visual organs: ( i ) many SW genes and a few LW genes were expressed in the dorsal region of compound eyes, presumably for processing SW-skewed light from the sky; ( ii ) a few SW genes and many LW genes were expressed in the ventral region of compound eyes, probably for perceiving terrestrial objects; and ( iii ) expression of a specific LW gene was associated with ocelli. Our findings suggest that the stage- and region-specific expressions of the diverse opsin genes underlie the behavior, ecology, and adaptation of dragonflies.

Community assembly theory is founded on the premise that the relative importance of local environmental processes and dispersal shapes the compositional structure of metacommunities. The species sorting model predicts that assemblages are dominated by the environmental filtering of species that are readily able to disperse to suitable sites. We propose an ecophysiological hypothesis (EH) for the mechanism underlying the organization of species-sorting odonate metacommunities based on the interplay of thermoregulation, body size and the degree of sunlight availability in small-to-medium tropical streams. Due to thermoregulatory restrictions, the EH predicts (i) that larger species are disfavored in small streams and (ii) that streams exhibit a nested compositional pattern characterized by species' size distribution. To test the EH, we evaluate the longitudinal distribution of adult Odonata at 19 sites in 1st- to 6th-order streams in the Tropical Cerrado of Brazil. With increasing channel width, the total abundance and species richness of Anisoptera increased, while the abundance of Zygoptera decreased. The first axis of an ordination analysis of the species abundance data was directly related to channel width. Mean and maximum thorax size are positively correlated to channel width, but no relationship was found for the minimum thorax size, suggesting that there is no lower size constraint on the occurrence of these species. Additionally, a nested compositional pattern related to body size was observed. Our results support the EH and its use as an ecological assembly rule based on abiotic factors. Forest cover functions as a filter to determine which species successfully colonize a given site within a metacommunity. As a consequence, the EH also indicates higher treats for small-bodied zygopterans in relation to the loss of riparian forests in tropical streams.

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A successful copula formation between a male of Libellula fulva and a female of L. depressa was documented photographically on 23. 6. 2022 at a small stream in the Natura 2000 site Ličenca pri Poljčanah in NE Slovenia. This represents the first record of an anomalous mating attempt with copula formation between the species involved. Their distribution in Slovenia as well as syntopic and syntemporal observations in the country are presented and briefly discussed, as are the site-specific factors and aged female coloration that may have contributed to the described rare attempt of heterospecific mating. Dne 23. 6. 2022 je bila ob manjšem potočku v Natura 2000 območju Ličenca pri Poljčanah v SV Sloveniji foto dokumentirana uspešna tvorba paritvenega koleslja med samcem črnega ploščca Libellula fulva in samico modrega ploščca L. depressa. To je prvi zapis o poskusu parjenja s tvorbo paritvenega koleslja med vpletenima vrstama. Na kratko je predstavljena in obravnavana njuna razširjenost v Sloveniji ter prostorsko in časovno prekrivajoča se opazovanja v državi, prav tako pa so obravnavani specifični dejavniki na mestu opazovanja in obarvanost postarane samice, ki bi lahko prispevali k opisanemu redkemu poskusu heterospecifičnega parjenja.

Understanding why species range sizes vary is important for predicting the impact of environmental change on biodiversity. Here we use a multi‐variable approach in a phylogenetic comparative context to understand how four morphological, two ecological, and two eco‐geographical variables are associated with range size, latitudinal range and longitudinal range in 81 species of North‐American libellulid dragonflies. Our results show that: 1) migratory species and species with a more expanded basal hindwing lobe have a larger range size; 2) opposite to Rapoport's rule, latitudinal range is negatively correlated with mid‐range latitude; 3) longitudinal range is predicted by wing morphology and migration; 4) body size and larval habitat are not correlated with range size, latitudinal range or longitudinal range. These results suggest that dispersal‐related traits, such as wing shape and migratory status, are important factors in predicting the range size of libellulid dragonflies. In addition, the reverse Rapoport's rule suggests that more northern‐centred species might be more specialized than more southern‐centred species. We suggest that the variables predicting range size are likely imposed by taxon‐specific morphological, ecological, physiological and behavioural traits. Taxon‐specific knowledge is thus necessary to understand the dynamics of range sizes and is important to implement successful restoration and conservation plans of threatened species.

Among terrestrial arthropods, the dragonfly species Pantala flavescens is remarkable due to their nearly global distribution and extensive migratory ranges; the largest of any known insect. Capable of migrating across oceans, the potential for high rates of gene flow among geographically distant populations is significant. It has been hypothesized that P. flavescens may be a global panmictic population but no sufficient genetic evidence has been collected thus far. Through a population genetic analysis of P. flavescens samples from North America, South America, and Asia, the current study aimed to examine the extent at which gene flow is occurring on a global scale and discusses the implications of the genetic patterns we uncovered on population structure and genetic diversity of the species. This was accomplished using PCR-amplified cytochrome oxidase one (CO1) mitochondrial DNA data to reconstruct phylogenetic trees, a haplotype network, and perform molecular variance analyses. Our results suggested high rates of gene flow are occurring among all included geographic regions; providing the first significant evidence that Pantala flavescens should be considered a global panmictic population.

Large numbers of the Globe Skimmer dragonfly (Pantala flavescens) appear in the Maldives every October-December. Since they cannot breed on these largely waterless islands, it has recently been suggested that they are \"falling out\" during a trans-oceanic flight from India to East Africa. In addition, it has been suggested that this trans-oceanic crossing is just one leg of a multi-generational migratory circuit covering about 14,000-18,000 km. The dragonflies are presumed to accomplish this remarkable feat by riding high-altitude winds associated with the Inter-tropical Convergence Zone (ITCZ). While there is considerable evidence for this migratory circuit, much of that evidence is circumstantial. Recent developments in the application of stable isotope analyses to track migratory dragonflies include the establishment of direct associations between dragonfly wing chitin δ(2)H values with those derived from long-term δ(2)H precipitation isoscapes. We applied this approach by measuring wing chitin δ(2)H values in 49 individual Pantala flavescens from the November-December migration through the Maldives. Using a previously established spatial calibration algorithm for dragonflies, the mean wing δ(2)H value of -117±16 ‰ corresponded to a predicted mean natal ambient water source of -81 ‰, which resulted in a probabilistic origin of northern India, and possibly further north and east. This strongly suggests that the migratory circuit of this species in this region is longer than previously suspected, and could possibly involve a remarkable trans-Himalayan high-altitude traverse.

Abstract Odonates are important biological control agents for the control of insect pests and insect disease vectors of medical and veterinary importance. The present study was conducted to evaluate the odonate fauna of Swat, Pakistan from March to October 2019. A total of 200 specimens of odonates were collected from diverse habitats. The collected specimens of the order Odonata belonged to 5 families, three families of suborder Anisoptera namely Libellulidae, Gomphidae and Aeshnidae while two families of suborder Zygoptera (Chlorocyphidae and Coenagrionidae). The specimens were categorized into 12 genera and 22 species. Libellulidae was the dominant family (n = 138) accounting for 69% of the odonate fauna. Orthetrum was the dominant genus (n = 73) of suborder Anisoptera accounting for 36.5% of the odonate fauna. The least dominant genera were Anax, Paragomphus and Rhyothemis (n = 5 each) accounting each for 2.5% of the odonate fauna. In Zygoptera, the dominant genus was Ceriagrion (12.5%) and the least dominant genus was Ischnura (6%). Pantala flavescens (Fabricius, 1798) was the most abundant odonate species in the study area recorded from all surveyed habitats. Shannon Diversity Index (H) was 2.988 and Simpson Diversity Index (D) was 0.95 for the collected odonate fauna. The highest abundance of Odonata was recorded in August, September and May while no odonate species were recorded in January, February, November and December. Lotic water bodies were the most suitable habitats with abundant odonate fauna. Anax immaculifrons (Rambur, 1842) was the largest sized odonate species having a wingspan of 53.2±1.63 mm and body length of 56.3 ± 0.4 mm. The present study shows the status of odonate fauna of Swat, Pakistan in diverse habitats and seasonsonal variation throughout the year. Further work is recommended to bridge the gaps in the existing literature. Resumo Odonatos são importantes agentes de controle biológico para o controle de insetos-praga e vetores de doenças de insetos de importância médica e veterinária. O presente estudo foi conduzido para avaliar a fauna de odonatos de Swat, Paquistão, de março a outubro de 2019. Um total de 200 espécimes de odonatos foi coletado em diversos habitats. Os espécimes coletados da ordem Odonata pertenciam a cinco famílias, três famílias da subordem Anisoptera, a saber, Libellulidae, Gomphidae e Aeshnidae, enquanto duas famílias eram da subordem Zygoptera (Chlorocyphidae e Coenagrionidae). Os espécimes foram classificados em 12 gêneros e 22 espécies. Libellulidae foi a família dominante (n = 138), respondendo por 69% da fauna de odonatos. Orthetrum foi o gênero dominante (n = 73) da subordem Anisoptera, responsável por 36,5% da fauna de odonatos. Os gêneros menos dominantes foram Anax, Paragomphus e Rhyothemis (n = 5 cada), representando cada um 2,5% da fauna de odonatos. Em Zygoptera, o gênero dominante foi Ceriagrion (12,5%), e o gênero menos dominante foi Ischnura (6%). Pantala flavescens (Fabricius, 1798) foi a espécie de odonato mais abundante na área de estudo, registrada em todos os habitats pesquisados. O Índice de Diversidade de Shannon (H) foi de 2,988, e o Índice de Diversidade de Simpson (D) foi de 0,95 para a fauna de odonatos coletados. A maior abundância de Odonata foi registrada em agosto, setembro e maio, enquanto nenhuma espécie de Odonata foi registrada em janeiro, fevereiro, novembro e dezembro. Corpos d’água lóticos foram os habitats mais adequados, com abundante fauna de odonatos. Anax imaculifrons (Rambur, 1842) foi a espécie de odonato de maior tamanho, com envergadura de 53,2 ± 1,63 mm e comprimento do corpo de 56,3 ± 0,4 mm. O presente estudo mostrou o status da fauna de odonatos de Swat, Paquistão, em diversos habitats e variação sazonal ao longo do ano. Recomenda-se trabalho adicional para preencher as lacunas na literatura existente.

Predation presents specific behavioral characteristics for each species, and the interaction between prey and predator influences the structuring of the food web. Concerning insects, predation can be affected in different ways, such as exposure to chemical stressors, e.g., pesticides. Therefore, analyses were carried out of the effects of exposure to insecticide fipronil and the herbicide 2,4-D on predation, parameters of food selectivity, and the swimming behavior of two neotropical predatory aquatic insects of the families Belostomatidae (giant water bugs) and larvae of Libellulidae (dragonfly). These predatory insects were exposed for 24 h to a commercial formulation of the chlorophenoxy herbicide, 2,4-D at nominal concentrations of 200, 300, 700, and 1400 μg L−1, and to a commercial formulation of the phenylpyrazole insecticide, fipronil at nominal concentrations of 10, 70, 140, and 250 µg L−1. In a control treatment, the insects were placed in clean, unspiked water. At the end of the exposure, the maximum swimming speed of the predators was evaluated. Afterward, the predators were placed in clean water in a shared environment for 24 h with several prey species, including the cladoceran Ceriodaphnia silvestrii, larvae of the insect Chironomus sancticaroli, the amphipod Hyalella meinerti, the ostracod Strandesia trispinosa, and the oligochaete Allonais inaequalis for 24 h. After this period, the consumed prey was counted. The results reveal that predators from both families changed prey consumption compared with organisms from the control treatment, marked by a decrease after exposure to fipronil and an increase in consumption caused by 2,4-D. In addition, there were changes in the food preferences of both predators, especially when exposed to the insecticide. Exposure to fipronil decreased the swimming speed of Belostomatidae individuals, possibly due to its neurotoxic effect. Exposure to the insecticide and the herbicide altered prey intake by predators, which could negatively influence the complex prey–predator relationship and the functioning of aquatic ecosystems in contaminated areas.