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Citizen science is essential for nationwide ecological surveys of species distribution. While the accuracy of the information collected by beginner participants is not guaranteed, it is important to develop an automated system to assist species identification. Deep learning techniques for image recognition have been successfully applied in many fields and may contribute to species identification. However, deep learning techniques have not been utilized in ecological surveys of citizen science, because they require the collection of a large number of images, which is time-consuming and labor-intensive. To counter these issues, we propose a simple and effective strategy to construct species identification systems using fewer images. As an example, we collected 4,571 images of 204 species of Japanese dragonflies and damselflies from open-access websites (i.e., web scraping) and scanned 4,005 images from books and specimens for species identification. In addition, we obtained field occurrence records (i.e., range of distribution) of all species of dragonflies and damselflies from the National Biodiversity Center, Japan. Using the images and records, we developed a species identification system for Japanese dragonflies and damselflies. We validated that the accuracy of the species identification system was improved by combining web-scraped and scanned images; the top-1 accuracy of the system was 0.324 when trained using only web-scraped images, whereas it improved to 0.546 when trained using both web-scraped and scanned images. In addition, the combination of images and field occurrence records further improved the top-1 accuracy to 0.668. The values of top-3 accuracy under the three conditions were 0.565, 0.768, and 0.873, respectively. Thus, combining images with field occurrence records markedly improved the accuracy of the species identification system. The strategy of species identification proposed in this study can be applied to any group of organisms. Furthermore, it has the potential to strike a balance between continuously recruiting beginner participants and updating the data accuracy of citizen science.

Field surveys in wetlands are limited by the difficulty in accessing the site, hazards during surveys, and the risk of disturbing the ecosystem. Thus, the use of unoccupied aerial vehicles (UAVs) can overcome these limiting factors and can assist in monitoring small organisms, such as plants and insects, that are unique to wetlands, aiding in wetland management and conservation. This study aimed to demonstrate the effectiveness of a survey method that uses a small drone equipped with a telephoto lens to monitor dragonflies, which are unique to wetlands and have been difficult to survey quantitatively, especially in large wetlands. In this study, the main target species of dragonflies was Nannophya pygmaea, which is the world’s smallest dragonfly (about 20 mm long). The study area was Mizorogaike wetland (Kita Ward, Kyoto City, Japan). The UAV was flown at a low speed at an altitude of 4 m to 5 m, and images were taken using 7× telephoto lens on Mavic 3 (7× optical and 4× digital). A total of 107 dragonflies of seven species were identified from the photographs taken by the drone. N. pygmaea, about 20 mm long, was clearly identified. Eighty-five dragonflies belonging to N. pygmaea were identified from the images. Thus, by using a small drone equipped with a telephoto lens, the images of N. pygmaea were captured, and the effects of downwash and noise were reduced. The proposed research method can be applied to large wetlands that are difficult to survey in the field, and can thus provide new and important information pertaining to wetland management and conservation. This research method is highly useful for monitoring wetlands as it is non-invasive, does not require the surveyor to enter the wetland, requires little research effort, and can be repeated.

Insects, despite possessing relatively small brains, exhibit noteworthy adaptive behaviors, making them intriguing subjects for understanding learning mechanisms. This study explores the learning capabilities of dragonfly larvae (Anisoptera: Aeshnidae) in conditioning experiments, shedding light on the cognitive processes that underpin their remarkable abilities. As apex predators, dragonflies play a crucial role in ecosystems, necessitating a diverse range of learning behaviors for survival and reproductive success. We addressed whether dragonfly larvae can differentiate between different colored stimuli and associate color with prey. Our experimental design demonstrated that dragonfly larvae are able to recognize conditioning stimuli. The findings contribute valuable insights into the cognitive abilities of dragonflies, suggesting that these insects can learn and discriminate colors of stimuli. Overall, this research broadens our understanding of insect learning and cognition, contributing to the broader field of animal behavior and memory., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Although ponds are rich ecosystems for the maintenance of aquatic biodiversity, in many regions of the world, they have been adversely affected by anthropogenic changes in surrounding landscapes. Dragonflies (Insecta: Odonata) are characterized by larval phases that are closely associated with aquatic ecosystems and can accordingly serve as useful indicators of the quality of these environments. In this study, we evaluated the patterns of abundance, richness, and taxonomic composition of adult Odonata in artificial and natural ponds located in the Legal Amazon of Maranhão, which have been exposed to different levels of disturbance. We analysed how the composition of the Odonata assemblages varies between natural and artificial ponds and also assessed to what extent artificial ponds and degraded natural ponds are able to maintain Odonata biodiversity. Our results indicate that the abundance, richness, and composition of Odonata among the monitored ponds were adversely impacted by more disturbed landscapes, with greater abundance and richness being recorded in preserved natural ponds. Although the degraded artificial and natural ponds have Odonata diversities comparable to those of the preserved natural ponds, the latter tend to be characterized by unique and exclusive species, thereby indicating the urgent need for measures designed to protect these natural ecosystems. [ABSTRACT FROM AUTHOR]

A total of 19 species of odonates, including eight species of Anisoptera (dragonflies) and 11 species of Zygoptera (damselflies), were recorded along the Tirthan River, Great Himalayan National Park Conservation Area (GHNPCA), Himachal Pradesh. Among these species, 17 were reported from the area for the first time. With the addition of these new records the number of odonates known from the GHNPCA is increased to 23 species representing 18 genera and eight families. Indothemis carnatica, Agriocnemis femina, and Argiocnemis rubescens are reported for the first time from the western Himalayan region. The study found a significant change in the species composition of odonates over a period of 18 years in the area, which may be due to changes in microhabitat conditions associated with climate change. [ABSTRACT FROM AUTHOR]

The present research focuses on the timing of wing–wing interaction that benefits the aerodynamic force of a dragonfly in hovering flight at Reynolds number 1350. A 3-D numerical simulation method, called the system coupling, was utilised by implementing a two-way coupling between the transient structural and flow analysis. We further explore the aerodynamic forces produced at different phase angles on the forewing and hindwing during the hovering flight condition of a dragonfly. A pair of dragonfly wings is simulated to obtain the force generated during flapping at a 60° inclination stroke plane angle with respect to the horizontal. The hovering flight is simulated by varying the phase angle and the inter-distance between the two wings. We observe a significant enhancement in the lift (16%) of the hindwing when it flaps in-phase with the forewing and closer to the forewing, maintaining an inter-wing distance of 1.2 cm (where cm is the mean chord length). However, for the same condition, the lift of the hindwing reduces by 9% when the wings are out of phase/counterstroke flapping. These benefits and drawbacks are dependent on the timing of the interactions between the forewing and hindwing. The time of interaction of wake capture, wing–wing interaction, dipole structure and development of root vortex are examined by 2-D vorticity of the flow field and isosurface of the 3-D model dragonfly. From the isosurface, we found that the root vortex elicited at the root of the hindwing in counter-flapping creates an obstacle for the shedding of wake vortices, which results in reduction of vertical lift during the upstroke of flapping. Hence, at the supination stage, a dragonfly uses a high rotation angle for the hovering flight mode. It is observed that the system coupling method was found to be more efficient and exhibited better performance. The present numerical methodology shows a very close match to the previously reported results. [ABSTRACT FROM AUTHOR]

Dynamic signals are a widespread phenomenon in several taxa, usually associated with intraspecific communication. In contrast, dynamic iridescent signals are detectable only at specific angles of illumination; hence, the animal can hide the signal to avoid detection when necessary. This structural coloration is mostly dependent on the illumination, the contrast against the background and the vision of the receiver. Complex behavioural displays can be coupled with structural coloration to create dynamic visual signals that enhance these functions. Here, we address whether iridescence of the males of a damselfly that inhabits dark rainforests, Chalcopteryx scintillans , can be considered a dynamic visual signal. We analyse whether coloration is perceived by conspecifics, while reducing detectability to eavesdroppers against three types of backgrounds. Our results suggest that the visual background affects the detectability of male hindwings by different receivers, mostly predators and prey. We discuss whether these results and the angle dependence of colour could indicate a mechanism to avoid unwanted intraspecific interactions or even to lure both predators and prey. We conclude that the main functions of the dynamic iridescent signal are to communicate with conspecifics while hindering the signal for prey, adding evidence of the multifunctionality of structural coloration coupled with behavioural displays in animals. [ABSTRACT FROM AUTHOR]

The Dragonfly mission to Titan represents the first use of a large-scale radioisotope power source in that environment; as such little is known of its potential effects on the surface or near-surface atmosphere. These effects represent backgrounds it will be necessary to subtract from the spacecraft's instrumentation data. Repurposing a Monte Carlo code model of the generator built for previous neutronic investigations with the addition of electron detectors allows for the determination of the degree to which the radiation fields from the generator may ionize the surrounding atmosphere and generate interference with the lander's conductivity measurements. Results showed good agreement with experimental data undertaken at the Idaho National Laboratory using the F-2 generator flown on the Perseverance Mars rover, and showed that the interference with readings taken in the daytime on Titan when atmospheric conductivity is expected to be low may be substantial. • MCNP Model of MMRTG, Dragonfly drone hull section & Titan/Earth atmospheres. • Ionization of dry Titan atmosphere greater than humid Earth atmosphere. • Conductivity within spacecraft hull significantly enhanced by backscatter. • Simulation results verified against empirical results taken at Idaho National Lab. • Open question of effect of methane humidity requires experimental work. [ABSTRACT FROM AUTHOR]

Pharmaceutically active compounds (PhACs) have been shown to accumulate in aquatic and riparian food-webs. Yet, our understanding of how temperature, a key environmental factor in nature, affects uptake, biotransformation, and the subsequent accumulation of PhACs in aquatic organisms is limited. In this study, we tested to what extent bioconcentration of an anxiolytic drugs (temazepam and oxazepam) is affected by two temperature regimes (10 and 20 °C) and how the temperature affects the temazepam biotransformation and subsequent accumulation of its metabolite (oxazepam) in aquatic organisms. We used European perch (Perca fluviatilis) and dragonfly larvae (Sympetrum sp.), which represent predator and prey species of high ecological relevance in food chains of boreal and temperate aquatic ecosystems. Experimental organisms were exposed to target pharmaceuticals at a range of concentrations (0.2–6 µg L−1) to study concentration dependent differences in bioconcentration and biotransformation. We found that the bioconcentration of temazepam in perch was significantly reduced at higher temperatures. Also, temperature had a strong effect on temazepam biotransformation in the fish, with the production and subsequent accumulation of its metabolite (oxazepam) being two-fold higher at 20 °C compared to 10 °C. In contrast, we found no temperature dependency for temazepam bioconcentration in dragonfly larvae and no detectable biotransformation of the parent compound that would result in measurable concentrations of oxazepam in this organism. Our results highlight that while organisms may share the same aquatic ecosystem, their exposure to PhACs may change differently across temperature gradients in the environment.

Odonata are biodiversity indicators that adequately represent many aquatic and semi-aquatic animal species. We recorded over two field seasons a rich lentic community of Odonata (18 species) in a large artificial freshwater reservoir (ca. 55 ha) built 40 years ago. The release of water from the dam in summer for crop irrigation leads to the desiccation of large parts of the reservoir, which prevents the reproduction of half of the species of this Odonata community. We identify two adaptations that allow eight species to cope with desiccation, i.e., a precocious breeding period allowing the emergence of adults before the retreat of water, or a delayed adult emergence due to egg diapause from oviposition to the end of winter. The reservoir acts thus as an ecological trap for individuals of 10 species that developed elsewhere and were attracted to the site without successfully breeding there. As consequence of the local population extinction at each generation, the presence of individuals of these 10 species at the reservoir depends on source-sink population dynamics in the landscape. In the context of global warming that encourages the creation of artificial freshwater reservoirs, the multiplication of such sinks could threaten the persistence in the landscape of species maladapted to desiccation.

The vehicular ad hoc network, VANET, is one of the most popular and promising technologies in intelligent transportation today. However, VANET is susceptible to several vulnerabilities that result in an intrusion. This intrusion must be solved before VANET technology can be adopted. In this study, we suggest a unique machine learning technique to improve VANET’s effectiveness. The proposed method incorporates two phases. Phase I detects the DDoS attack using a novel machine learning technique called SVM-HHO, which provides information about the vehicle. Phase II mitigates the impact of a DDoS attack and allocates bandwidth using a reliable resources management technique based on the hybrid whale dragonfly optimization algorithm (H-WDFOA). This proposed model could be an effective technique predicting and utilizing reliable information that provides effective results in smart vehicles. The novel machine learning-based technique was implemented through MATLAB and NS2 platforms. Network quality measurements included congestion, transit, collision, and QoS awareness cost. Based on the constraints, a different cost framework was designed. In addition, data preprocessing of the QoS factor and total routing costs were considered. Rider integrated cuckoo search (RI-CS) is a novel optimization algorithm that combines the concepts of the rider optimization algorithm (ROA) and cuckoo search (CS) to determine the optimal route with the lowest routing cost. The enhanced hybrid ant colony optimization routing protocol (EHACORP) is a networking technology that increases efficiency by utilizing the shortest route. The shortest path of the proposed protocol had the lowest communication overhead and the fewest number of hops between sending and receiving vehicles. The EHACORP involved two stages. To find the distance between cars in phase 1, EHACORP employed a method for calculating distance. Using starting point ant colony optimization, the ants were guided in phase 2 to develop the shortest route with the least number of connections to send information. The relatively short approach increases protocol efficiency in every way. The pairing of DCM and SBACO at H-WDFOA-VANET accelerated packet processing, reduced ant search time, eliminated blind broadcasting, and prevented stagnation issues. The delivery ratio and throughput of the H-WDFOA-packet VANET benefitted from its use of the shortest channel without stagnation, its rapid packet processing, and its rapid convergence speed. In conclusion, the proposed hybrid whale dragonfly optimization approach (H-WDFOA-VANET) was compared with industry standard models, such as rider integrated cuckoo search (RI-CS) and enhanced hybrid ant colony optimization routing protocol (EHACORP). With the proposed method, throughput could be increased. The proposed system had energy consumption values of 2.00000 mJ, latency values of 15.61668 s, and a drop at node 60 of 0.15759. Additionally, a higher throughput was achieved with the new method. With the suggested method, it is possible to meet the energy consumption targets, delay value, and drop value at node 60. The proposed method reduces the drop value at node 80 to 0.15504, delay time to 15.64318 s, and energy consumption to 2.00000 mJ. These outcomes demonstrate the effectiveness of our proposed method. Thus, the proposed system is more efficient than existing systems.

Dragonflies are highly skilled and successful aerial predators that are even capable of selectively attending to one target within a swarm. Detection and tracking of prey is likely to be driven by small target motion detector (STMD) neurons identified from several insect groups. Prior work has shown that dragonfly STMD responses are facilitated by targets moving on a continuous path, enhancing the response gain at the present and predicted future location of targets. In this study, we combined detailed morphological data with computational modeling to test whether a combination of dendritic morphology and nonlinear properties of NMDA receptors could explain these observations. We developed a hybrid computational model of neurons within the dragonfly optic lobe, which integrates numerical and morphological components. The model was able to generate potent facilitation for targets moving on continuous trajectories, including a localized spotlight of maximal sensitivity close to the last seen target location, as also measured during in vivo recordings. The model did not, however, include a mechanism capable of producing a traveling or spreading wave of facilitation. Our data support a strong role for the high dendritic density seen in the dragonfly neuron in enhancing non-linear facilitation. An alternative model based on the morphology of an unrelated type of motion processing neuron from a dipteran fly required more than three times higher synaptic gain in order to elicit similar levels of facilitation, despite having only 20% fewer synapses. Our data support a potential role for NMDA receptors in target tracking and also demonstrate the feasibility of combining biologically plausible dendritic computations with more abstract computational models for basic processing as used in earlier studies.

Dragonflies possess two pairs of wings and the interactions between forewing (FW) and hindwing (HW) play an important role in dragonfly flight. The effects of tandem-wing (TW) interactions on the aerodynamic performance of dragonfly hovering have been investigated. Numerical simulations of single-wing hovering without interactions and TW hovering with interactions are conducted and compared. It is found that the TW interactions reduce the lift coefficient of FW and HW by 7.36% and 20.25% and also decrease the aerodynamic power and efficiency. The above effects are mainly caused by the interaction between the vortex structures of the FW and the HW, which makes the pressure of the wing surface and the flow field near the wings change. During the observations of dragonfly flight, it is found that the phase difference (γ) is not fixed. To explore the influence of phase difference on aerodynamic performance, TW hovering with different phase differences is studied. The results show that at γ = 22.5°, dragonflies produce the maximum lift which is more than 20% of the body weight with high efficiency; at γ = 180°, dragonflies generate the same lift as the body weight.

Land use changes and the ways that natural resources are extracted and used pose severe threats to freshwater ecosystems globally. This is particularly pronounced in developing and densely populated countries, such as Rwanda. In-depth understanding of how ecosystems respond to threats could guide their restoration, conservation, and better management. The advancement of ecological monitoring tools is crucial for freshwater conservation. We developed and implemented an odonate-based tool, the Rwanda Dragonfly Biotic Index (RDBI), tailored to freshwater ecosystems in Rwanda as a metric to identify conservation priority sites and to monitor their restoration. The RDBI is determined based on three sub-indices: Distribution-Based Score (DBS), Threat-Based Score (TBS) and Sensitivity-Based Score (SBS). Species level-DBS increases from those that are widespread across all ecological zones to those that are restricted to only one ecological zone; TBS for a species ranges from those that are of least concern to those that are critically endangered, as per IUCN Red List; Species’ SBS increases from those thriving in a highly disturbed habitat to those occurring only in a relatively intact habitat. Using RDBI, we identified hotspot habitats for odonates in Rwanda and benchmark sites for restoration. Hotspots are defined based on species richness, presence of unique species, and RDBI scores. Benchmark sites for restoration are habitats with the highest RDBI in each ecological zone. The value of using RDBI in ecosystem monitoring rests on the fact that it can help identify priority sites for conservation, and it uses organisms that are charismatic and relatively easy to identify. This is essential for citizen engagement and drawing a long-term link between policymaking, on-the-ground practices, and impacts on freshwater ecosystems.

Dragonflies are highly skilled and successful aerial predators that are even capable of selectively attending to one target within a swarm. Detection and tracking of prey is likely to be driven by small target motion detector (STMD) neurons identified from several insect groups. Prior work has shown that dragonfly STMD responses are facilitated by targets moving on a continuous path, enhancing the response gain at the present and predicted future location of targets. In this study, we combined detailed morphological data with computational modeling to test whether a combination of dendritic morphology and nonlinear properties of NMDA receptors could explain these observations. We developed a hybrid computational model of neurons within the dragonfly optic lobe, which integrates numerical and morphological components. The model was able to generate potent facilitation for targets moving on continuous trajectories, including a localized spotlight of maximal sensitivity close to the last seen target location, as also measured during in vivo recordings. The model did not, however, include a mechanism capable of producing a traveling or spreading wave of facilitation. Our data support a strong role for the high dendritic density seen in the dragonfly neuron in enhancing non-linear facilitation. An alternative model based on the morphology of an unrelated type of motion processing neuron from a dipteran fly required more than three times higher synaptic gain in order to elicit similar levels of facilitation, despite having only 20% fewer synapses. Our data support a potential role for NMDA receptors in target tracking and also demonstrate the feasibility of combining biologically plausible dendritic computations with more abstract computational models for basic processing as used in earlier studies. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natura Sloveniae: Revija za Terensko Biologijo / Journal of Field Biology is the property of Natura Sloveniae and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Dragonflies are not an unknown miracle for most humans. These fascinating insects come under the Order - "Odonata," the title which is also shared by much slender and glossy bodied damselflies. Coming under the Phylum Arthropoda, and class Insecta, Odonata is the order that defines them. Anisoptera and Zygoptera are the sub-orders that define dragonflies and damselflies, respectively. Odonates have marked their presence even before dinosaurs dominated land and play a major role in the evolutionary history. They are primarily aquatic insects and spend their larval stages inside water, before emerging out for their first flight. Being carnivores in nature, they maintain an ecological balance, along with showing a high degree of predation. Along with these, the amphibious life style of odonates is observed to make them ecological indicators; that is, indicating the "well-being" or the pollution level of an environment with its presence. Apreliminary checklist of the odonate species of Veliyathunadu has been documented from September 2019 to February 2020. This study reveals the influence of water or rain on the diversity of odonates, and it was found that the diversity tends to be higher during the monsoon period (September-October-November). Line transect method along with checklist method was used for sampling analysis and data collection. Graphs were plotted from the 6-month data and the checklist was prepared. [ABSTRACT FROM AUTHOR]

The species of Odonata are highly predacious on invertebrates, especially the immature stages, which are generalist predators. The Odonate diversity of protected areas of Gujarat state, India was studied from August, 2014 to July, 2017. Fifteen protected areas of Gujarat were surveyed. A total of 60 species (41 species of Anisoptera and 19 species of Zygoptera) belonging to 40 genera under 8 families and two suborders were recorded. Maximum species (54) were recorded from Purna Wildlife Sanctuary of Dang district followed by Vansda National Park (44 species) of Navsari district. Amongst the protected wetlands, maximum species (47) were recorded from Nalsarovar Bird Sanctuary. [ABSTRACT FROM AUTHOR]

Many aquatic macroinvertebrates that require specific habitat niches are expected to relocate in response to global warming-induced climate change. For some species, relocation will not be possible because of geographic constraints or complete loss of the required habitat. Data compiled by Theischinger et al. (2018) was used to identify some species of Odonata at risk of extinction due to loss of habitat caused by climate change. While numerous species are at risk, this paper details only examples of habitats most likely to be impacted. Twelve species requiring these habitats are discussed. Species most at risk are those requiring alpine, sub-alpine and montane habitats. The combined effects of reduced rainfall and increased temperatures have been identified as the factors most likely to degrade these habitats catastrophically. Australia has limited alpine, sub-alpine and montane regions, and little or no alternative habitat for these species. Also, species requiring spring-fed streams are at risk due to reduced renewal of groundwater, while those that inhabit large slow-flowing rivers, particularly in the Murray Darling Basin, are likely to be impacted by algal blooms. [ABSTRACT FROM AUTHOR]

The final emergence of the Coromandel Marsh Dart Damselfly Ceriagrion coromandelianum was studied for 50 days (22 January–12 March, 2011) from the botanical garden of Hislop College, Nagpur, India, (a semi controlled site) where small underground cement tubs/tanks are used to grow macrophytes by the Botany department. In C. coromandelianum emergence is asynchronous, diurnal and occurs between 07.00h and 18.00h. Stage-I starts when the ultimate instar nymph of C. coromandelianum leaves the water body, searches for a suitable place and then begins to shudder its body to detach the trapped pharate from the nymphal exuvia. The pharate exerts pressure on the thoracic tergites to split the cuticle. Stage-II starts when the head and thorax of the pharate emerges out of the split exuvia. The pharate struggles to remove its trapped body from the nymphal exuvia. During Stage-III, the wings expand but are opaque; pigmentation of the body occurs simultaneously all over the body. Soon the whole body develops its species specific coloration while the expanding wings gain transparency, unfold and separate out and now the imago is ready for its maiden flight. Stages I, II, and III occupy 31.66%, 11.73%, and 56.60% of the total moulting period, respectively. A total of 243 emergences occurred during the observation period, 158 emergences occurred in tanks containing Pistia stratiotes, while 65 emergences in tubs containing Nymphaea nouchali indicating that C. coromandelianum prefers P. stratiotes over N. nouchali for oviposition. Twenty deaths were recorded during the present observation. Failure to moult (15%) and failure to emerge completely out of the exuvia (85%) were the two reasons for mortality.

Co-occurrence of species with similar trophic requirements, such as odonates, seems to depend both on them occupying different microhabitats and differing in their life-cycles. The life cycles of the dragonflies Boyeria irene and Onychogomphus uncatus were studied in two consecutive years, mainly by systematic sampling of larvae in seven permanent head courses that constitute the upper basin of the River Águeda, western Spain, in the central part of the ranges of these two species. The size ranges of the last five larval stadia of both species were established based on biometric data. The eggs of the egg-overwintering aeshnid hatched in late spring and early summer and for the gomphid hatching peaked in middle-late summer. Both species showed mixed voltinism with "cohort splitting". B. irene had a dominant three-year development (partivoltinism), with some developing in two years (semivoltinism). O. uncatus requires four, sometimes three years to complete development (all partivoltine). B. irene larvae spent the winter before emergence in the last three, maybe four stadia, as a "summer species". O. uncatus mainly behaved as a "spring species", most larvae spending the last winter in the final larval stadium.

In this present communication we report the occurrence of additional 13 Odonate species from the Asansol-Durgapur Industrial Area, West Bengal, India, making the total 76. This paper reports the first record of Libellago indica (Fraser, 1928) and first photographic records of Macromia flavicincta Selys, 1874 from West Bengal. It also reports the range extension of Macromia cingulata Rambur, 1842 from the Purulia District to Paschim Bardhaman District. [ABSTRACT FROM AUTHOR]

Interspecific interactions, such as competition, are among the key factors that determine the distribution, abundance and diversity of organisms in natural communities of aquatic ecosystems. However, a marked reduction in the environmental integrity of streams may lead to modifications of the natural dynamics of these communities, including co‐occurrence patterns and body size. In the Amazon, the replacement of forests by production systems is one of the leading causes of alterations to riverine ecosystem. The insects of the order Odonata (dragonflies and damselflies) are predators known to compete for environmental resources but are also sensitive to environmental changes such as those caused by shifts in land use. In this scenario, the present study evaluated species co‐occurrence and body size patterns in adult odonates found at preserved and altered Amazonian streams, to determine whether there are morphological differences among the species that enable their coexistence. During the study, 98 streams in the eastern Amazon region were sampled, and a habitat integrity index (HII) was used to evaluate the integrity of each stream (based on variables such as the condition of the riparian vegetation and channel, and land use). Ten male individuals were selected from each species, and nine morphometric measurements were taken from each individual. A total of 3588 specimens were collected and distributed in nine families, 49 genera and 134 species. We found a non‐random pattern of co‐occurrence in the species of the odonate suborder Zygoptera and a random pattern in the suborder Anisoptera, in both preserved and altered streams. We found morphological divergence between pairs of zygopteran species, in the whole sample and both categories of stream integrity separately. No such morphological divergence was found in the pairs of anisopteran species. The distribution patterns of odonate species are limited by specific environmental processes, especially in preserved environments and in specialists, such as most zygopterans. Zygopteran species have more specific microhabitat requirements, which could explain this pattern, whereas anisopterans prefer open environments, which usually have a greater supply of resources, although there tends to be less microhabitat heterogeneity, which leads to reduced competition. Given this, future studies should use limiting similarity (e.g. morphological attributes) in addition to environmental and spatial factors to better understand the factors structuring these communities. Among these mechanisms, the effects of common ancestry (phylogenetic inertia) and biogeography are important factors that should also be considered in future studies. [ABSTRACT FROM AUTHOR]

In cooperation with biologists, we discuss the problem of animal species protection with the usage of modern technologies, namely mobile phones. In our work, we consider the problem of dragonfly image classification, where the aim is given to a preprocessing—segmentation of a dragonfly body from a background. To solve the task, we improve U-Net architecture by ResNeXt cells firstly. Further, we focus on the reasonability of features in neural networks with cardinality dimension and propose the cascaded way of re-using the features among blocks in particular cardinal dimensions. The reuse of the already trained features leads to composing more robust features and more efficient usage of neural network parameters. We test our cascaded cells together with three various U-Net versions for four different settings of hyperparameters with the conclusion that the system of cascaded features leads to higher accuracy than the other versions with the same number of parameters. Also, the cascaded cells are more robust to overfitting the dataset. The obtained results are confirmed on two additional public datasets. [ABSTRACT FROM AUTHOR]

The article provides information on the species composition and distribution of dragonfly larvae inhabiting the inland water basins of Azerbaijan (Aggol, Mehman, Nakhalikhchala, Hajigabul, Garaoglan, Yetim Kur, Marzli, Garkhun, Aynali).The article describes the species composition and distribution of dragonfly larvae inhabiting the inland water basins (Aggol, Mehman, Nakhalikhchala, Hajigabul lakes and Garaoglan, Yetim Kur, Marzli, Garkhun, Aynali) of Azerbaijan by seasons. Larvae are considered one of the most important tools for malaria prevention. At the same time, the larvae of dragonflies form the basis of the feed of fish and other aquatic animals. [ABSTRACT FROM AUTHOR]

The most well‐known use of silk among spiders is the formation of webs to capture flying prey. However, spiders have evolved many different foraging strategies involving silk, including the capture and subsequent manipulate of prey prior to consumption. Herein, I report on the use of silk lines by a long‐jawed spider from the Tetragnatha genus to move a large prey item vertically through the air. Field observations revealed a long‐jawed spider attaching multiple silk lines across the body of an adult dragonfly that had recently emerged from its final moult and attaching these threads to overlying vegetation to incrementally haul the prey item from the surface of a waterbody. My observations suggest that some Tetragnatha spiders are able to move large prey items that are much heavier then themselves using a series of silk lines that allow lift to be accomplished in a gradual and controlled manner. This is an interesting finding, given that other individuals from the same population were using web structures to passively catch much smaller, flying prey. This indicates that some Tetragnatha spiders not only participate in the mobile pursuit of prey but that they possess multiple foraging strategies that may allow them to exploit a larger number of prey types. [ABSTRACT FROM AUTHOR]

Many studies have reported that the interaction between water mite larvae and their Odonata hosts affects mating success, flight, and longevity. Males and females of Odonata species collected in the steppes and coastal plains (Pampa Biome) of Rio Grande do Sul were analyzed. Mites were removed when present and the prevalence and intensity of parasites was calculated. The aim of this study was to search and report new Odonata hosts species that are parasitized by water mite larvae and also to evaluate the prevalence and intensity rates; the differences in mite occurrence and frequency between males and females, and between thorax and abdomen of the dragonflies and damselflies in the southern Pampa biome located in Rio Grande do Sul. A total of 162 larval mites were found associated to two Odonata families: Coenagrionidae (Acanthagrion lancea Selys, 1876, Ischnura capreolus Hagen, 1861 and Ischnura fluviatilis Selys, 1876) and Libelullidae (Micrathyria ocellata Martin, 1897 and Perithemis mooma Kirby, 1889). All mites were identified as Arrenurus (Arrenurus) sp. (Arrenuridae) and showed high numbers when attached to I. capreolus (55.5%), I. fluviatilis (33.3%), followed by low numbers on M. ocellata (6.1%), A. lancea (3.7%), and P. mooma (1.2%). Mites were found on males and females of I. capreolus and I. fluviatilis, females of A. lancea and P. mooma and in M. ocellata only in males. As the parasitized Odonata species are generalist and abundant in all water body types, traits associated with mating and oviposition or larval behavior are believed to explain the frequency of parasitism in these species. [ABSTRACT FROM AUTHOR]

Latency and reliability are essential parameters for enabling ultra-reliable low-latency communication (URLLC). Therefore, an approach for node identification that satisfies the requirements of latency and reliability for URLLC based on the formation of swarms by dragonflies, called dragonfly node identification algorithm (DNIA), is proposed. This method maps bio-natural systems and legacy communication into metrics of URLLC, i.e., latency and reliability, for node identification. A performance analysis demonstrates that the new paradigm for mapping the metrics, i.e., latency and reliability, in terms of nodes (food source) and noise (predators) provides another dimension for URLLC. A comparative analysis proves that DNIA demonstrates significant impact on the improvement of latency, reliability, packet loss rate, as well as throughput. The robustness and efficiency of the proposed DNIA are evaluated using statistical analysis, convergence rate analysis, Wilcoxon test, Friedman rank test, and analysis of variance on classical as well as modern IEEE Congress on Evolutionary Computation 2014 benchmark functions. Moreover, simulation results show that DNIA outperforms other bioinspired optimization algorithms in terms of cumulative distributive function and average node identification errors. The conflicting objectives in the tradeoff between low latency and high reliability in URLLC are discussed on a Pareto front, which shows the improved and accurate approximation for DNIA on a true Pareto front. Further, DNIA is benchmarked against standard functions on the Pareto front, providing significantly superior results in terms of coverage as well as convergence. [ABSTRACT FROM AUTHOR]

The study of corrugated wings has become acquainted in the field of insect flight in recent times. Recent studies on the aerodynamic effects of a corrugated wing are based on insects like the Dragonfly; whereas the likes of Fruitfly (Drosophila Melanogaster) usually go unobserved due to their smaller size. Consequently, the behaviour of these corrugations is found to be anomalous especially in the low and ultra-low Reynolds number region. Therefore, the main aim of this study is to understand the aerodynamic effects of the corrugated airfoil present in the wing of a Fruitfly; by conducting a geometric parametric study during a static non-flapping flight at 1000 Re. In this computational study, a 2-D section of the corrugated wing along the chord is considered. The parametric study helps in understanding the effects of varying number of corrugations, angle of corrugations and the presence of a hump at the trailing edge. The dimensions were scaled to a suitable reference value to additionally compare the corrugated airfoil of Fruitfly to that of a Dragonfly. The present study shows that the aerodynamic performance of the corrugated wing in terms of cl and cd are predominantly governed by the subtle geometric variations that can largely impact the formation of bubbles, vortex zones, and their mutual interaction. The reduction in the number of leading edge corrugations improved the cl/cd ratio and reduction in the corrugation angle helped produce higher lift. The presence of a trailing edge hump also improved the stall angle with a better flow re-attachment. The presence of corrugation at the trailing edge proved to be more beneficial compared to the model with corrugations at the leading edge. This also helped in understanding, the aerodynamic superiority of the trailing edge corrugations present in the Dragonfly's wing when compared to the Fruitfly's. [ABSTRACT FROM AUTHOR]

This paper aims to model the daily evolution for particulate matter concentrations of less than 1 μm (PM1), 2.5 μm (PM2.5), 4 μm (PM4), 10 μm (PM10), and PM-Total, based on weather factors (WF), by using the hybrid dragonfly-SVMr algorithm. Hourly data on atmospheric concentrations of PMi and WF were recorded simultaneously at an automatic air quality check station located at an urban site in Algiers, using the fine dust measurement device, Fidas® 200. The number of data collected on PM was 540 measurements. In this study, the meta-heuristic dragonfly algorithm (DA) was used in order to select the optimal hyper-parameters of the Support Vector Machine model. For this, a MATLAB® program based on the dragonfly optimization algorithm coupled with the SVM regression algorithm has been written in order to correlate for the PMi concentrations. The obtained results show that the established model has good predictive performance, with a coefficient of determination R2 = 0.98 and root of the mean square error RMSE = 1.9261. [ABSTRACT FROM AUTHOR]

Ecological rules such as Bergmann’s rule and the temperature–size rule state that body-size decline is a universal response to warm temperatures in both homeotherms and poikilotherms. In the present study, we investigated the biological responses of Nannophya koreana, an endangered dragonfly species in Korea, by comparing body size in two habitats with large differences in water temperature, Mungyong-si (MG, terraced paddy fields) and Muui-do (MU, a mountainous wetland). To conserve the dragonfly populations, the collected larvae were photographed and released, and their head widths and body lengths were measured. There was no difference in the annual mean air temperature and precipitation between the two sites; however, the annual mean water temperature was substantially lower in MU than in MG. There was little difference in larval head width between the two sites; however, body length in the MU population was smaller than that in the MG population. Larval growth rate per 100-degree-days was 0.75 mm for MG and 1.16 for MU. The relationship between temperature and body size of N. koreana larvae showed opposite trends to Bergmann’s rule and the temperature–size rule. Since the larval growth period during a year in MU was shorter than that in MG, the MU population potentially exhibits a higher growth rate as a mechanism of compensating for the low water temperature. Our study established the relationship between temperature and body size of N. koreana in two wetlands that had an obvious difference in water temperature despite being geographically close. The results highlight the importance of considering detailed factors such as habitat type when studying the temperature–size responses of organisms.

Research on the microbiomes of animals has increased substantially within the past decades. More recently, microbial analyses of aquatic invertebrates have become of increased interest. The storage method used while collecting aquatic invertebrates has not been standardized throughout the scientific community, and the effects of common storage methods on the microbial composition of the organism is unknown. Using crayfish and dragonfly nymphs collected from a natural pond and crayfish maintained in an aquarium, the effects of two common storage methods, preserving in 95% ethanol and freezing at −20 °C, on the invertebrate bacterial microbiome was evaluated. We found that the bacterial community was conserved for two sample types (gut and exoskeleton) of field-collected crayfish stored either in ethanol or frozen, as was the gut microbiome of aquarium crayfish. However, there were significant differences between the bacterial communities found on the exoskeleton of aquarium crayfish stored in ethanol compared to those that were frozen. Dragonfly nymphs showed significant differences in gut microbial composition between species, but the microbiome was conserved between storage methods. These results demonstrate that preserving field-collected specimens of aquatic invertebrates in 95% ethanol is likely to be a simple and effective sample preservation method for subsequent gut microbiome analysis but is less reliable for the external microbiome.

Odonates (Insecta: Odonata) are important insects in the food chains of freshwater environments around the world, being used as a model species for areas of behavior and analysis of environmental quality. In Brazil, especially in the Northeastern region, both knowledge about the distribution and molecular information of odonate species found in the two main biomes of the region is still limited. Aiming to improve these issues, here, we carried out an Odonata survey in two locations and built a DNA barcode database for species from the state of Paraíba. In total, 15 first records were reported for this Brazilian state and 142 specimens from 27 genera and 45 species had their ‘Folmer’ cytochrome c oxidase subunit I (COI) fragment evaluated. The database we generated includes data for 70% of the Odonata species found in Paraíba state. For 16 species, this is the first DNA barcode available in public sequence repositories. Our results demonstrate that using the COI in the regional scale can help identify and delimit those evaluated. Eight species (17%) showed a low percentage of differentiation (

Dragonflies perform dramatic aerial manoeuvres when chasing targets but glide for periods during cruising flights. This makes dragonflies a great system to explore the role of passive stabilizing mechanisms that do not compromise manoeuvrability. We challenged dragonflies by dropping them from selected inverted attitudes and collected 6-degrees-of-freedom aerial recovery kinematics via custom motion capture techniques. From these kinematic data, we performed rigid-body inverse dynamics to reconstruct the forces and torques involved in righting behaviour. We found that inverted dragonflies typically recover themselves with the shortest rotation from the initial body inclination. Additionally, they exhibited a strong tendency to pitch-up with their head leading out of the manoeuvre, despite the lower moment of inertia in the roll axis. Surprisingly, anaesthetized dragonflies could also complete aerial righting reliably. Such passive righting disappeared in recently dead dragonflies but could be partially recovered by waxing their wings to the anaesthetised posture. Our kinematics data, inverse dynamics model and wind-tunnel experiments suggest that the dragonfly's long abdomen and wing posture generate a rotational tendency and passive attitude recovery mechanism during falling. This work demonstrates an aerodynamically stable body configuration in a flying insect and raises new questions in sensorimotor control for small flying systems. [ABSTRACT FROM AUTHOR]

Predation is a key ecological interaction affecting populations and communities. Climate warming can modify this interaction both directly by the kinetic effects of temperature on biological rates and indirectly through integrated behavioural and physiological responses of the predators and prey. Temperature dependence of predation rates can further be altered by predator‐induced plasticity of prey locomotor activity, but empirical data about this effect are lacking.We propose a general framework to understand the influence of predator‐induced developmental plasticity on behavioural thermal reaction norms in prey and their consequences for predator–prey dynamics. Using a mesocosm experiment with dragonfly larvae (predator) and newt larvae (prey), we tested if the predator‐induced plasticity alters the elevation or the slope of the thermal reaction norms for locomotor activity metrics in prey. We also estimated the joint predator–prey thermal response in mean locomotor speed, which determines prey encounter rate, and modelled the effect of both phenomena on predator–prey population dynamics.Thermal reaction norms for locomotor activity in prey were affected by predation risk cues but with minor influence on the joint predator–prey behavioural response. We found that predation risk cues significantly decreased the intercept of thermal reaction norm for total activity rate (i.e. all body movements) but not the other locomotor activity metrics in the prey, and that prey locomotor activity rate and locomotor speed increased with prey density.Temperature had opposite effects on the mean relative speed of predator and prey as individual speed increased with temperature in predators but decreased in prey. This led to a negligible effect of body temperature on predicted prey encounter rates and predator–prey dynamics. The behavioural component of predator–prey interaction varied much more between individuals than with temperature and the presence of predation risk cues in our system.We conclude that within‐population variation in locomotor activity can buffer the influence of body temperature and predation risk cues on predator–prey interactions, and further research should focus on the magnitude and sources of behavioural variation in interacting species to predict the impact of climate change on predator–prey interactions and food web dynamics. [ABSTRACT FROM AUTHOR]

The dragonfly fauna of four reserves located in Campos y Malezales ecoregion, Misiones Province, was studied between 2014 and 2018. Thirty-six species and eight morphotypes, belonging to six families of Anisoptera and Zygoptera were identified, representing together 22% of the known species in the Province. Libellulidae was the family with the highest number of species recorded (22 species) followed by Coenagrionidae (15 species). Two species were new records, one for Argentina (Minagrion waltheri Selys), and one for Misiones province (Tholymis citrina Hagen). [ABSTRACT FROM AUTHOR]

Understanding of dragonfly distributions is often geographically comprehensive but less so in ecological terms.White‐faced darter (Leucorhinnia dubia) is a lowland peatbog specialist dragonfly which has experienced population declines in Great Britain. White‐faced darter is thought to rely on peat‐rich pool complexes within woodland, but this has not yet been empirically tested.We used dragonfly recording data collected by volunteers of the British Dragonfly Society from 2005 to 2018 to model habitat preference for white‐faced darter using species distribution models across Great Britain and, with a more detailed landcover data set, specifically in the North of Scotland.Across the whole of Great Britain, our models used the proportion of coniferous forest within 1 km as the most important predictor of habitat suitability but were not able to predict all current populations in England.In the North of Scotland, our models were more successful and suggest that habitats characterised by native coniferous forest and areas with high potential evapotranspiration represent the most suitable habitat for white‐faced darter.We recommend that future white‐faced darter monitoring should be expanded to include areas currently poorly surveyed but with high suitability in the North of Scotland.Our results also suggest that white‐faced darter management should concentrate on maintaining Sphagnum rich‐pool complexes and the maintenance and restoration of native forests in which these pool complexes occur. [ABSTRACT FROM AUTHOR]

Entomopathogenic microsporidia are pathogens of various arthropods and therefore cause disease in important host species ranging from agricultural pests to beneficial insects. Here, we investigated three genera of entomopathogenic microsporidia from dragonflies； these were isolated in Kanagawa, Japan, in 2014. In total, the infection rate was 0.85%（16 of the 1,886 surveyed dragonfly adults）. Four strains of microsporidia selected from infected Orthetrum albistylum speciosum（Uhler）（Odonata: Libellulidae）adults were measured for spore size and analyzed at the molecular level. According to spore size, the four strains were roughly divided into two groups. Analysis of smallsubunit ribosomal RNA sequences indicated that the microsporidia strains belonged to the Trachipleistophora, Vavraia, and Paranosema clusters. Microsporidia species that are closely related to the strains isolated in this study have previously been reported to infect insects other than dragonflies. Therefore, we suggest the possibility that the microsporidian strains we isolated in O. albistylum speciosum may also infect other insect species. [ABSTRACT FROM AUTHOR]

Within Europe, the damselfly Coenagrion hylas has a very limited distribution and is regarded as a vulnerable species. For studying migration and population connectivity in the Central European populations, 10 microsatellite markers were developed for this species. The loci were screened on 24 individuals collected at Lech valley, Tyrol, Austria. The values for expected and observed heterozygosity ranged from 0.192 to 0.802 and from 0.208 to 0.917, respectively. All developed markers were polymorphic. [ABSTRACT FROM AUTHOR]

The complete life cycle of O. ferruginea is described for the first time, represent the first complete life cycle described for an odonate in Mexico. The 17 larval instars obtained are described and illustrated in detail, from prolarva through F-0. Two egg batches of different females were obtained in the field and were subsequently reared in the laboratory. Eggs and larvae of the batches were raised under 26°C controlled temperature conditions until they reached instars F-6 and F-5. An extra collection of wild organisms was made in order to complete the life cycle from F-5. Only four of the wild larvae managed to complete the last five missing larval instars at 30°C. Larvae of the youngest instars (F-15 to F-8) were fed nauplii of Artemia franciscana, while F-7 to F-0 were fed larvae of Culicidae and Chironomidae. Larval life cycle from F-0 to F-16 lasted average of 186 days. [ABSTRACT FROM AUTHOR]

Demography and territorial behavior of Hetaerina cruentata was studied along three lowland streams located at Norte de Santander department in the Colombian Andean region. Adult damselflies (N: 278) were individually marked, and using their recapture histories we estimated survival, longevity, sex ratio, age groups and population size at each location. We found no evidence for survival differences between ages and sexes. However, the proportion of resighted individuals was lower for females, and the sex ratio was male-biased in all populations. Although we recorded few reproductive events, a high number of male-male agonistic interactions were registered around midday. During reproductive behavior, we observed brief wing displays as signals between males and females, and the formation of the tandem position, followed by the intra-male sperm translocation and copulation (mean duration 11.3 min). After copulation, the pair in tandem looked for suitable sites to oviposit, and then the male broke tandem and perched on the vegetation while the female laid eggs partially or completely underwater. The recapture probability was time-dependent, which suggests that the alternation of rainy and sunny days during the study may be generating differences in the demography of the three H. cruentata populations. [ABSTRACT FROM AUTHOR]