QSPR for the prediction of critical micelle concentration of different classes of surfactants using machine learning algorithms

The determination of the critical micelle concentration (CMC) is a crucial factor when evaluating surfactants, making it an essential tool in studying the properties of surfactants in various industrial fields. In this present research, we assembled a comprehensive set of 593 different classes of surfactants including, anionic, cationic, nonionic, zwitterionic, and Gemini surfactants to establish a link between their molecular structure and the negative logarithmic value of critical micelle concentration (pCMC) utilizing quantitative structure-property relationship (QSPR) methodologies. Statistical analysis revealed that a set of 14 significant Mordred descriptors (SlogP, GATS6d, nAcid, GATS8dv, GATS4dv, PEOE_VSA11, GATS8d, ATS0p, GATS1d, MATS5p, GATS3d, NdssC, GATS6dv and EState_VSA4), along with temperature, served as appropriate inputs. Different machine learning methods, such as multiple linear regression (MLR), random forest regression (RFR), artificial neural network (ANN), and support vector regression (SVM), were employed in this study to build QSPR models. According to the statistical coefficients of QSPR models, SVR with Dragonfly hyperparameter optimization (SVR-DA) was the most accurate in predicting pCMC values, achieving (R2 = 0.9740, Q2 = 0.9739, r‾m2 = 0.9627, and Δrm2 = 0.0244) for the entire dataset.

Rare eggshell structure in Odonata: Lindenia tetraphylla (Van der Linden) (Anisoptera: Gomphidae)

Lindenia tetraphylla (Van der Linden, 1825) eggs exhibit an egg structure that is very rare in other Gomphidae species. They have a well-developed surface reticulation structure. The anterior pole of the egg has a small, rounded micropylar area consisting of seven orifices arranged radially around a central area. The posterior pole has a sessile, truncated cone that carries 55-65 coiled filaments. The filament structure found at the posterior pole of the egg has been observed in the gomphid species Lestinogomphus africanus (Fraser, 1926), Ictinogomphus australis (Selys, 1873), and I. rapax (Rambur, 1842). However, L. tetraphylla eggs differ from these species in both morphology and filament structure. This study provides a detailed analysis of the ultrastructure of L. tetraphylla eggs using scanning electron microscopy, and the functional and taxonomic significance of the eggshell are discussed. RESEARCH HIGHLIGHTS: The aim of this study is to examine the ultrastructure of the L. tetraphylla eggshell, emphasizing its function and taxonomic value. In this context, the general morphology of the egg, the reticulations on its surface, the micropylar region and micropylar structure, and the posterior filament coil were examined. In this study, the ultrastructure of L. tetraphylla egg was examined for the first time using scanning electron microscopy (SEM). As a result of the examination, it was detected for the first time that the posterior filament coil, which is rarely seen in odonate eggs, is also present in L. tetraphylla eggs. By comparing the L. tetraphylla egg with the eggs of I. ferox, I. rapax, I. australis, and L. africanus species, which are similar in terms of the posterior filament coil, the features that distinguish the L. tetraphylla egg.

Significant biomagnification of methylmercury in songbird nestlings through a rice-based food web: Insights from stable mercury isotopes

To elucidate the sources and transfer of mercury (Hg) in terrestrial food chains, particularly in heavily Hg-contaminated rice paddy ecosystems, we collected rice leaves, invertebrates, and Russet Sparrow nestlings from a clear food chain and analyzed the dietary compositions and potential Hg sources using stable Hg isotopes coupled with a Bayesian isotope mixing model (BIMM). Our findings indicated that MeHg exposure is dominant through the dietary route, with caterpillars, grasshoppers, and katydids being the main prey items, while the less provisioned spiders, dragonflies, and mantises contributed the most of the Hg to nestlings. We found minimal MIF but certain MDF in this terrestrial food chain and identified two distinct MeHg sources of dietary exposure and maternal transfer. We firstly found that the dietary route contributed substantially (almost tenfold) more MeHg to the nestlings than maternal transfer. These findings offer new insights into the integration of Hg from the dietary route and maternal transfers, enhancing our understanding of fluctuating Hg exposure risk during the nestling stage. Our study suggested that Hg isotopes combined with BIMM is an effective approach for tracing Hg sources in birds and for gaining in-depth insight into the trophic transfers and biomagnification of MeHg in food chains.

Desirable Strong and Tough Adhesive Inspired by Dragonfly Wings and Plant Cell Walls

The production of wood-based panels has a significant demand for mechanically strong and flexible biomass adhesives, serving as alternatives to nonrenewable and toxic formaldehyde-based adhesives. Nonetheless, plywood usually exhibits brittle fracture due to the inherent trade-off between rigidity and toughness, and it is susceptible to damage and deformation defects in production applications. Herein, inspired by the microstructure of dragonfly wings and the cross-linking structure of plant cell walls, a soybean meal (SM) adhesive with great strength and toughness was developed. The strategy was combined with a multiple assembly system based on the tannic acid (TA) stripping/modification of molybdenum disulfide (MoS2@TA) hybrids, phenylboronic acid/quaternary ammonium doubly functionalized chitosan (QCP), and SM. Motivated by the microstructure of dragonfly wings, MoS2@TA was tightly bonded with the SM framework through Schiff base and strong hydrogen bonding to dissipate stress energy through crack deflection, bridging, and immobilization. QCP imitated borate chemistry in plant cell walls to optimize interfacial interactions within the adhesive by borate ester bonds, boron-nitrogen coordination bonds, and electrostatic interactions and dissipate energy through sacrificial bonding. The shear strength and fracture toughness of the SM/QCP/MoS2@TA adhesive were 1.58 MPa and 0.87 J, respectively, which were 409.7% and 866.7% higher than those of the pure SM adhesive. In addition, MoS2@TA and QCP gave the adhesive good mildew resistance, durability, weatherability, and fire resistance. This bioinspired design strategy offers a viable and sustainable approach for creating multifunctional strong and tough biobased materials.

An evolutionary innovation for mating facilitates ecological niche expansion and buffers species against climate change

One of the drivers of life's diversification has been the emergence of "evolutionary innovations": The evolution of traits that grant access to underused ecological niches. Since ecological interactions can occur separately from mating, mating-related traits have not traditionally been considered factors in niche evolution. However, in order to persist in their environment, animals need to successfully mate just as much as they need to survive. Innovations that facilitate mating activity may therefore be an overlooked determinant of species' ecological limits. Here, we show that species' historical niches and responses to contemporary climate change are shaped by an innovation involved in mating-a waxy, ultra-violet-reflective pruinescence produced by male dragonflies. Physiological experiments in two species demonstrate that pruinescence reduces heating and water loss. Phylogenetic analyses show that pruinescence is gained after taxa begin adopting a thermohydrically stressful mating behavior. Further comparative analyses reveal that pruinose species are more likely to breed in exposed, open-canopy microhabitats. Biogeographic analyses uncover that pruinose species occupy warmer and drier regions in North America. Citizen-science observations of Pachydiplax longipennis suggest that the extent of pruinescence can be optimized to match the local conditions. Finally, temporal analyses indicate that pruinose species have been buffered against contemporary climate change. Overall, these historical and contemporary patterns show that successful mating can shape species' niche limits in the same way as growth and survival.

Multidimensional vibrational circular dichroism for insect wings: Comparison of species

This study reports the microscopic measurements of vibrational circular dichroism (VCD) on four different insect wings using a quantum cascade laser VCD system equipped with microscopic scanning capabilities (named multi-dimensional VCD [MultiD-VCD]). Wing samples, including (i) beetle, Anomala albopilosa (female), (ii) European hornet, Verspa crabro flavofasciata Cameron, 1903 (female), (iii) tiny dragonfly, Nannophya pygmae Rambur, 1842 (male), and (iv) dragonfly, Symetrum gracile Oguma, 1915 (male), were used in this study. Two-dimensional patterns of VCD signals (~10 mm × 10 mm) were obtained at a spatial resolution of 100 μm. Measurements covered the absorption peaks assigned to amides I and II in the range of 1500-1740 cm-1 . The measurements were based on the enhancement of VCD signals for the stereoregular linkage of peptide groups. The patterns were remarkably dependent on the species. In samples (i) and (ii), the wings comprised segregated domains of protein aggregates of different secondary structures. The size of each microdomain was approximately 100 μm. In contrast, no clear VCD spectra were detected in samples (iii) and (iv). One possible reason was that the chain of stereoregular polypeptides was too short to achieve VCD enhancement in samples (iii) and (iv). Notably, the unique features were only observed in the VCD spectra because the IR spectra were nearly the same among the species. The VCD results hinted at the connection of protein microscopic structures with the wing flapping mechanisms of each species.

Chemical composition and mosquitocidal properties of essential oil from Indian indigenous plants Ocimum tenuiflorum L. and Ocimum americanum L. against three vector mosquitoes

Mosquitoes stand out as the most perilous and impactful vectors on a global scale, transmitting a multitude of infectious diseases to both humans and other animals. The primary objective of the current research was to assess the effectiveness of EOs from Ocimum tenuiflorum L. and Ocimum americanum L. in controlling Anopheles stephensi Liston. Culex quinquefasciatus Say and Aedes aegypti L. mosquitoes. The larvae, pupae and eggs of the mosquitoes were exposed to four different concentrations (6.25-50 ppm). The tested EOs resulted in >99-100 % mortality at 120 h for the eggs of all examined mosquito species. It also showed robust larvicidal and pupicidal activity with LC50 and LC90 values of 17-39, 23-60 ppm and 46-220, and 73-412 ppm against Aedes, Culex and Anopheles mosquito species, respectively, at 24 h of treatment. The Suitability Index or Predator Safety Factor demonstrated that the EOs extracted from O. tenuiflorum L. and O. americanum L. did not cause harm to P. reticulata, D. indicus (water bug), G. affinis and nymph (dragonfly). GC-MS analysis identified the major probable constituents of the oil, including Phenol, 2-Methoxy-4-(1-Propenyl)- (28.29 %); 1-Methyl-3-(1'-Methylcyclopropyl) Cyclopentene (46.46 %); (E,E,E)-3,7,11,15-Tetramethylhexadeca-1,3,6,10,14-Pentaene (18.91 %) and 1,3-Isobenzofurandione, 3a,4,7,7a-Tetrahydro-4,7-Dimethyl (33.02 %). These constituents may play a significant role in the mosquitocidal activity of the oil. The same results were identified in the formulation prepared from the EOs. This marks the first report confirming the successful utilization of EOs derived from O. tenuiflorum L. and O. americanum L. in mosquito population control initiatives.

Competitive Displacement and Agonistic Character Displacement, or the Ghost of Interference Competition

AbstractInterference competition can drive species apart in habitat use through competitive displacement in ecological time and agonistic character displacement (ACD) over evolutionary time. As predicted by ACD theory, sympatric species of rubyspot damselflies (Hetaerina spp.) that respond more aggressively to each other in staged encounters differ more in microhabitat use. However, the same pattern could arise from competitive displacement if dominant species actively exclude subordinate species from preferred microhabitats. The degree to which habitat partitioning is caused by competitive displacement can be assessed with removal experiments. We carried out removal experiments with three species pairs of rubyspot damselflies. With competitive displacement, removing dominant species should allow subordinate species to shift into the dominant species' microhabitat. Instead, we found that species-specific microhabitat use persisted after the experimental removals. Thus, the previously documented association between heterospecific aggression and microhabitat partitioning in this genus is most likely a product of divergence in habitat preferences caused by interference competition in the evolutionary past.

Habitat and dissolved organic carbon modulate variation in the biogeochemical drivers of mercury bioaccumulation in dragonfly larvae at the national scale

We paired mercury (Hg) concentrations in dragonfly larvae with water chemistry in 29 U.S. national parks to highlight how ecological and biogeochemical context (habitat, dissolved organic carbon [DOC]) influence drivers of Hg bioaccumulation. Although prior studies have defined influences of biogeochemical variables on Hg production and bioaccumulation, it has been challenging to determine their influence across diverse habitats, regions, or biogeochemical conditions within a single study. We compared global (i.e., all sites), habitat-specific, and DOC-class models to illuminate how these controls on biotic Hg vary. Although the suite of important biogeochemical factors across all sites (e.g., aqueous Hg, DOC, sulfate [SO42-], and pH) was consistent with general findings in the literature, contrasting the restricted models revealed more nuanced controls on biosentinel Hg. Comparing habitats, aqueous (filtered) total mercury (THg) and SO42- were important in lentic systems whereas aqueous (filtered) methylmercury (MeHg), DOC, pH, and SO42- were important in lotic and wetland systems. The ability to identify important variables varied among habitats, with less certainty in lentic (model weight (W) = 0.05) than lotic (W = 0.11) or wetland habitats (W = 0.23), suggesting that biogeochemical drivers of bioaccumulation are more variable, or obscured by other aspects of Hg cycling, in these habitats. Results revealed a contrast in the importance of aqueous MeHg versus aqueous THg between DOC-classes: in low-DOC sites (<8.5 mg/L), availability of upstream inputs of MeHg appeared more important for bioaccumulation; in high-DOC sites (>8.5 mg/L) THg was more important, suggesting a link to in-situ controls on bioavailability of Hg for MeHg production. Mercury bioaccumulation (indicated by bioaccumulation factor) was more efficient in low DOC-class sites, likely due to reduced partitioning of aqueous MeHg to DOC. Together, findings highlight substantial variation in the drivers of Hg bioaccumulation and suggest consideration of these factors in natural resource management and decision-making.

Main drivers of dragonflies and damselflies (Insecta; Odonata) metacommunities in streams inside protected areas in the Brazilian Amazon

The evaluation of environmental and spatial influence in freshwater systems is crucial for the conservation of aquatic diversity. So, we evaluated communities of Odonata in streams inside and outside sustainable use areas in the Brazilian western Amazon. We predicted that these streams would differ regarding habitat integrity and species α and β diversity. We also predict that environmental and spatial variables will be important for both suborders, but with more substantial effects on Zygoptera species, considering their nature of forest-specialist. The study was conducted in 35 streams, 19 inside and 16 outside sustainable use areas. The streams outside presented high species richness, abundance, and number of exclusive forest-specialist species from Zygoptera and higher scores of habitat integrity. In contrast, one sustainable use area presented the lowest values of these metrics. Besides, we found that environmental and spatial variables were significantly associated to Zygoptera species composition, but not with Anisoptera, which can be explained by their cosmopolitan nature. Our results indicated that an interplay between environmental and spatial processes determines the structure of the metacommunities of Zygoptera. The less effective dispersal rates and narrow ecological tolerance of Zygoptera species make them more influenced by local conditions and dispersal limitation, and more sensible to habitat modifications. We highlight the importance of improving the local management of the sustainable use areas by environmental agencies, mainly on areas that are losing their capacity to maintain the aquatic fauna, and implementation of social policies toward traditional people.

Exposure to the insecticide, imidacloprid, impairs predator-recognition learning in damselfly larvae

Many aquatic organisms use chemosensory information to learn about local predation threats, but contaminants in their environment may impair such cognitive processes. Neonicotinoids are a class of water-soluble systemic insecticides that have become a major concern in aquatic systems. In this study, we explored how a 10-day exposure to various concentrations (0, 0.1, 1.0, or 10.0 μg/L) of the neonicotinoid imidacloprid affects the learned recognition of predator odour by non-target damselfly larvae (Lestes spp). Unexposed larvae and those exposed to the low concentration (0.1 μg/L) demonstrated an appropriate learned response to a novel predator odour following a conditioning with the odour paired with chemical alarm cues. However, such learning failed to occur for larvae that were exposed to imidacloprid concentrations of 1.0 and 10.0 μg/L. Thus, either the cognitive processing of the chemical information was impaired or the chemistry of one or both of the conditioning cues was altered, making them ineffective for learning. In a second experiment, we found evidence for this latter hypothesis. In the absence of background imidacloprid exposure, larvae did not show significant learned responses to the predator odour when the conditioning cues were mixed with imidacloprid (initial pulse solution of 3.0 μg/L) at the start of conditioning (reaching a final concentration of 0.01 μg/L). These findings indicate that even low levels of imidacloprid can have important implications for chemosensory cognition of non-target species in aquatic environments.

Statistical distribution of micro and macro pores in acrylic bone cement- effect of amount of antibiotic content

Aseptic loosening due to mechanical failure of bone cement is considered to be a leading cause of revision of joint replacement systems. Detailed quantified information on the number, size and distribution pattern of pores can help to obtain a deeper understanding of the bone cement's fatigue behavior. The objective of this study was to provide statistical descriptions for the pore distribution characteristics of laboratory bone cement specimens with different amounts of antibiotic contents. For four groups of bone cement (Palacos) specimens, containing 0.3, 0.6, 1.2 and 2.4 wt/wt% of telavancin antibiotic, seven samples per group were micro computed tomography scanned (38.97 μm voxel size). The images were first preprocessed in Mimics and then analyzed in Dragonfly, with the level of threshold being set such that single-pixel pores become visible. The normalized pore volume data of the specimens were then used to extract the logarithmic histograms of the pore densities for antibiotic groups, as well as their three-parameter Weibull probability density functions. Statistical comparison of the pore distribution data of the antibiotic groups using the Mann-Whitney non-parametric test revealed a significantly larger porosity (p < 0.05) in groups with larger added antibiotic contents (2.4 and 0.6 wt/wt% vs 0.3 wt/wt%). Further analysis revealed that this effect was associated with the significantly larger frequency of micropores of 0.1-0.5 mm diameter (p < 0.05) in groups with larger antibiotic content (2.4 wt/wt% vs and 0.6 and 0.3 wt/wt%), implying that the elution of the added antibiotic produces micropores in this diameter range mainly. Based on this observation and the fatigue test results in the literature, it was suggested that micropore clusters have a detrimental effect on the mechanical properties of bone cement and play a major role in initiating fatigue cracks in highly antibiotic added specimens.

Reusable mechano-bactericidal surface with echinoid-shaped hierarchical micro/nano-structure

Biofilms formed owing to the attachment of bacteria to surfaces have caused various problems in industries such as marine transportation/logistics and medicine. In response, many studies have been conducted on bactericidal surfaces, and nanostructured surfaces mimicking cicada and dragonfly wings are emerging as candidates for mechano-bactericidal surfaces. In specific circumstances involving mechano-bactericidal activity, certain nanostructured surfaces could exhibit their bactericidal effects by directly deforming the membranes of bacteria that adhere to these nanostructures. Additionally, in most cases, debris of bacterial cells may accumulate on these nanostructured surfaces. Such accumulation poses a significant challenge: it diminishes the mechano-bactericidal effectiveness of the surface, as it hinders the direct interaction between the nanostructures and any new bacteria that attach subsequently. In specific circumstances involving mechano-bactericidal activity, certain nanostructured surfaces could exhibit their bactericidal effects by directly deforming the membranes of bacteria that adhere to these nanostructures. Additionally, in most cases, debris of bacterial cells may accumulate on these nanostructured surfaces. Such accumulation poses a significant challenge: it diminishes the mechano-bactericidal effectiveness of the surface, as it hinders the direct interaction between the nanostructures and any new bacteria that attach subsequently.In other words, there is a need for strategies to remove the accumulated bacterial debris in order to sustain the mechano-bactericidal effect of the nanostructured surface. In this study, hierarchical micro/nano-structured surface (echinoid-shaped nanotextures were formed on Al micro-particle's surfaces) was fabricated using a simple pressure-less sintering method, and effective bactericidal efficiency was shown against E. coli (97 ± 3.81%) and S. aureus (80 ± 9.34%). In addition, thermal cleaning at 500 °C effectively eliminated accumulated dead bacterial debris while maintaining the intact Al2O3 nanostructure, resulting in significant mechano-bactericidal activity (E. coli: 89 ± 6.86%, S. aureus: 75 ± 8.31%). As a result, thermal cleaning maintains the intact nanostructure and allows the continuance of the mechano-bactericidal effect. This effect was consistently maintained even after five repetitive use (E. coli: 80 ± 16.26%, S. aureus: 76 ± 12.67%).

Ecological Implications on Aquatic Food Webs Due to Effects of Pesticides on Invertebrate Predators in a Neotropical Region

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.

Oxygen extraction efficiency of the tidally-ventilated rectal gills of dragonfly nymphs

Dragonfly nymphs breathe water using tidal ventilation, a highly unusual strategy in water-breathing animals owing to the high viscosity, density and low oxygen (O2) concentration of water. This study examines how well these insects extract O2 from the surrounding water during progressive hypoxia. Nymphs were attached to a custom-designed respiro-spirometer to simultaneously measure tidal volume, ventilation frequency and metabolic rate. Oxygen extraction efficiencies (OEE) were calculated across four partial pressure of oxygen (pO2) treatments, from normoxia to severe hypoxia. While there was no significant change in tidal volume, ventilation frequency increased significantly from 9.4 ± 1.2 breaths per minute (BPM) at 21.3 kPa to 35.6 ± 2.9 BPM at 5.3 kPa. Metabolic rate increased significantly from 1.4 ± 0.3 µl O2 min-1 at 21.3 kPa to 2.1 ± 0.4 µl O2 min-1 at 16.0 kPa, but then returned to normoxic levels as O2 levels declined further. OEE of nymphs was 40.1 ± 6.1% at 21.3 kPa, and did not change significantly during hypoxia. Comparison to literature shows that nymphs maintain their OEE during hypoxia unlike other aquatic tidal-breathers and some unidirectional breathers. This result, and numerical models simulating experimental conditions, indicate that nymphs maintain these extraction efficiencies by increasing gill conductance and/or lowering internal pO2 to maintain a sufficient diffusion gradient across their respiratory surface.

Filling knowledge gaps in insect conservation by leveraging genetic data from public archives

Insect decline has become a growing concern in recent years, with studies showing alarming declines in populations of several taxa. Our knowledge about genetic spatial patterns and evolutionary history of insects still exhibits significant gaps hindering our ability to effectively conserve and manage insect populations and species. Genetic data may provide valuable insights into the diversity and the evolutionary relationships of insects' species and populations. Public repositories, such as GenBank and BOLD, containing vast archives of genetic data with associated metadata, offer an irreplaceable resource for researchers contributing to our understanding of species diversity, population structure and evolutionary relationships. However, there are some issues in using these data, as they are often scattered and may lack accuracy due to inconsistent sampling protocols and incomplete information. In this paper we describe a curated georeferenced database of genetic data collected in GenBank and BOLD, for insects listed in the International Union for Conservation of Nature (IUCN) Italian Red Lists (dragonflies, bees, saproxylic beetles and butterflies). After querying these repositories, we performed quality control and data standardization steps. We created a dataset containing approximately 33 000 mitochondrial sequences and associated metadata about taxonomy, collection localities, geographic coordinates and IUCN Red List status for 1466 species across the four insect lists. We describe the current state of geographical metadata in queried repositories for species listed under different conservation status in the Italian Red Lists to quantify data gaps posing barriers to prioritization of conservation actions. Our curated dataset is available for data repurposing and analysis, enabling researchers to conduct comparative studies. We emphasize the importance of filling knowledge gaps in insect diversity and distribution and highlight the potential of this dataset for promoting other research fields like phylogeography, macrogenetics and conservation strategies. Our database can be downloaded through the Zenodo repository in SQL format. Database URL:  https://zenodo.org/records/8375181.

Optimal controller design for reactor core power stabilization in a pressurized water reactor: Applications of gold rush algorithm

Nuclear energy (NE) is seen as a reliable choice for ensuring the security of the world's energy supply, and it has only lately begun to be advocated as a strategy for reducing climate change in order to meet low-carbon energy transition goals. To achieve flexible operation across a wide operating range when it participates in peak regulation in the power systems, the pressurised water reactor (PWR) NE systems must overcome the nonlinearity problem induced by the substantial variation. In light of this viewpoint, the objective of this work is to evaluate the reactor core (main component) of the NE system via different recent optimization techniques. The PWR, which is the most common form, is the reactor under investigation. For controlling the movement of control rods that correspond with reactivity for power regulation the PWR, PID controller is employed. This study presents a dynamic model of the PWR, which includes the reactor core, the upper and lower plenums, and the piping that connects the reactor core to the steam alternator is analyzed and investigated. The PWR dynamic model is controlled by a PID controller optimized by the gold rush optimizer (GRO) built on the integration of the time-weighted square error performance indicator. Additionally, to exhibit the efficacy of the presented GRO, the dragonfly approach, Arithmetic algorithm, and planet optimization algorithm are used to adjust the PID controller parameters. Furthermore, a comparison among the optimized PID gains with the applied algorithms shows great accuracy, efficacy, and effectiveness of the proposed GRO. MATLAB\ Simulink program is used to model and simulate the system components and the applied algorithms. The simulation findings demonstrate that the suggested optimized PID control strategy has superior efficiency and resilience in terms of less overshoot and settling time.

Can warming accelerate the decline of Odonata species in experimental paddies due to insecticide fipronil exposure?

Systemic insecticides are one of the causes of Odonata declines in paddy fields. Since rising temperatures associated with global warming can contribute to strengthen pesticide toxicity, insecticide exposures under increasing temperatures may accelerate the decline of Odonata species in the future. However, the combined effects of multiple stressors on Odonata diversity and abundance within ecosystems under various environmental conditions and species interactions are little known. Here, we evaluate the combined effects of the insecticide fipronil and warming on the abundance of Odonata nymphs in experimental paddies. We show that the stand-alone effect of the insecticide exposure caused a significant decrease in abundance of the Odonata community, while nymphs decreased synergistically in the combined treatments with temperature rise in paddy water. However, impacts of each stressor alone were different among species. This study provides experimental evidence that warming could accelerate a reduction in abundance of the Odonata community exposed to insecticides (synergistic effect), although the strength of that effect might vary with the community composition in targeted habitats, due mainly to different susceptibilities among species to each stressor. Community-based monitoring in actual fields is deemed necessary for a realistic evaluation of the combined effects of multiple stressors on biodiversity.

Effects of acute and chronic chromium stress on the expression of heat shock protein genes and activities of antioxidant enzymes in larvae of Orthetrum albistylum

The dragonfly species Orthetrum albistylum, can accumulate heavy metals from its aquatic environment and thus serves as a biological indicator for monitoring and evaluating water quality. Heat shock proteins (HSPs) play important biological roles in resistance to various types of environmental stress. The full-length cDNA sequences of the heat shock cognate (hsc) 70 and heat shock protein (hsp) 70 genes were cloned from O. albistylum larvae. Relative levels of expression of hsc70 and hsp70 in the head, epidermis, midgut, and adipose tissue were measured by qRT-PCR after chronic and acute contamination of 5-8 instar larvae with chromium (Cr) solution, and under control conditions. Activities of superoxide dismutase (SOD) and catalase (CAT) in chronically contaminated larvae were also measured. Phylogenetic analysis revealed that the cloned hsc70 and hsp70 genes were highly homologous to known HSP70 family members reported in other insects. The mRNA levels of hsc70 and hsp70 did not differ significantly in various larval tissues. Under chronic chromium stress, hsc70 and hsp70 expression were upregulated to a maximum and then downregulated; hsp70 mRNA levels were higher than those of hsc70 at all concentrations of chromium. Under acute chromium stress, hsc70 expression was inhibited at low chromium concentrations and upregulated at chromium concentrations higher than 125 mg/L. However, hsp70 expression was higher than that in the control group and markedly higher than that of hsc70. Changes in SOD and CAT activities displayed consistent trends for different chronic chromium concentrations, first increasing and then decreasing over time. Collectively, these findings demonstrated the response of the HSP family of genes and antioxidant enzymes following exposure to heavy metal stress, as well as their potential applicability as biomarkers for monitoring environmental pollutants.

Niche differentiation, reproductive interference, and range expansion

Understanding species distributions and predicting future range shifts requires considering all relevant abiotic factors and biotic interactions. Resource competition has received the most attention, but reproductive interference is another widespread biotic interaction that could influence species ranges. Rubyspot damselflies (Hetaerina spp.) exhibit a biogeographic pattern consistent with the hypothesis that reproductive interference has limited range expansion. Here, we use ecological niche models to evaluate whether this pattern could have instead been caused by niche differentiation. We found evidence for climatic niche differentiation, but the species that encounters the least reproductive interference has one of the narrowest and most peripheral niches. These findings strengthen the case that reproductive interference has limited range expansion and also provide a counterexample to the idea that release from negative species interactions triggers niche expansion. We propose that release from reproductive interference enables species to expand in range while specializing on the habitats most suitable for breeding.

Genomic differentiation and niche divergence in the Hetaerina americana (Odonata) cryptic species complex

The evolution of reproductive barriers, that is, the speciation process, implies the limitation of gene flow between populations. Different patterns of genomic differentiation throughout the speciation continuum may provide insights into the causal evolutionary forces of species divergence. In this study, we analysed a cryptic species complex of the genus Hetaerina (Odonata). This complex includes H. americana and H. calverti; however, in H. americana two highly differentiated genetic groups have been previously detected, which, we hypothesize, may correspond to different species with low morphological variation. We obtained single nucleotide polymorphism (SNP) data for 90 individuals belonging to the different taxa in the complex and carried out differentiation tests to identify genetic isolation. The results from STRUCTURE and discriminant analysis of principal components (DAPC), based on almost 5000 SNPs, confirmed the presence of three highly differentiated taxa. Also, we found FST values above 0.5 in pairwise comparisons, which indicates a considerable degree of genetic isolation among the suggested species. We also found low climatic niche overlap among all taxa, suggesting that each group occurs at specific conditions of temperature, precipitation and elevation. We propose that H. americana comprises two cryptic species, which may be reproductively isolated by ecological barriers related to niche divergence, since the morphological variation is minimal and, therefore, mechanical barriers are probably less effective compared to other related species such as H. calverti.

Mosquitocidal Susceptibility and Non-Target Effects of Tricholoma equestre Mushroom (Agaricomycetes) on the Immature Stages of Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus

The worldwide scientific community is well aware that mosquitoes are the sole agents responsible for transmitting various dreadful diseases and critical illnesses caused by vector-borne pathogens. The primary objective of this current research was to evaluate the effectiveness of methanol extract from Tricholoma equestre mushroom in controlling the early life stages of Culex quinquefasciatus Say, Anopheles stephensi Liston, and Aedes aegypti (Linnaeus in Hasselquist) mosquitoes. The larvae, pupae and eggs of these mosquitoes were exposed to four different concentrations (62.5 to 500 ppm). After 120 h of treatment, the methanol extract of T. equestre exhibited ovicidal activity ranging from 66% to 80% against the eggs of the treated mosquitoes. It also demonstrated promising larvicidal and pupicidal activity with LC50 values of 216-300 and 230-309 ppm against the early life stages of all three mosquito species. Extensive toxicity studies revealed that the methanol extract from T. equestre had no harmful effects on non-target organisms. The suitability index (SI) or predator safety factor (PSF) indicated that the methanol extract did not harm Poecilia reticulata Peters 1859, (predatory fish), Gambusia affinis S. F. Baird & Girard 1853, dragonfly nymph and Diplonychus indicus Venkatesan & Rao 1871 (water-bug). Gas chromatography-mass spectrometry (GCMS) analysis identified key compounds, including 3-butenenitrile, 2-methyl-(25.319%); 1-butanol, 2-nitro-(18.87%) and oxalic acid, heptyl propyl ester (21.82%) which may be responsible for the observed activity. Furthermore, the formulation based on the methanol extract demonstrated similar effectiveness against all treated mosquitoes at the laboratory level and was found to be non-toxic to mosquito predators. This groundbreaking research represents the first confirmation that methanol extract from T. equestre could be effectively employed in preventing mosquito-borne diseases through mosquito population control programs.

New stem-anisopteran dragonflies in the Jurassic of China (Odonata: Epiproctophora)

The odonatan asiopterid Turanopteron sinensis sp. nov. and the juragomphid Oxfordgomphus trescellulae gen. et sp. nov. are described on the basis of two new fossil wings from the Middle-Upper Jurassic of Henan Province in China. These taxa belong to ancient, Toarcian epiproctophoran stem groups of Anisoptera Selys, 1854. They show important affinities with taxa from the Karatau entomofauna in Kazakhstan. These groups progressively decrease and were replaced by more modern clades of Anisoptera during the Late Jurassic.

Seasonal variation in dragonfly assemblage colouration suggests a link between thermal melanism and phenology

Phenology, the seasonal timing of life events, is an essential component of diversity patterns. However, the mechanisms involved are complex and understudied. Body colour may be an important factor, because dark-bodied species absorb more solar radiation, which is predicted by the Thermal Melanism Hypothesis to enable them to thermoregulate successfully in cooler temperatures. Here we show that colour lightness of dragonfly assemblages varies in response to seasonal changes in solar radiation, with darker early- and late-season assemblages and lighter mid-season assemblages. This finding suggests a link between colour-based thermoregulation and insect phenology. We also show that the phenological pattern of dragonfly colour lightness advanced over the last decades. We suggest that changing seasonal temperature patterns due to global warming together with the static nature of solar radiation may drive dragonfly flight periods to suboptimal seasonal conditions. Our findings open a research avenue for a more mechanistic understanding of phenology and spatio-phenological impacts of climate warming on insects.

Molecular Characterisation of Faecal Bacterial Assemblages Among Four Species of Syntopic Odonates

Factors such as host species, phylogeny, diet, and both timing and location of sampling are thought to influence the composition of gut-associated bacteria in insects. In this study, we compared the faecal-associated bacterial taxa for three Coenagrion and one Enallagma damselfly species. We expected high overlap in representation of bacterial taxa due to the shared ecology and diet of these species. Using metabarcoding based on the 16S rRNA gene, we identified 1513 sequence variants, representing distinct bacterial 'taxa'. Intriguingly, the damselfly species showed somewhat different magnitudes of richness of ZOTUs, ranging from 480 to 914 ZOTUs. In total, 921 (or 60.8% of the 1513) distinct ZOTUs were non-shared, each found only in one species, and then most often in only a single individual. There was a surfeit of these non-shared incidental ZOTUs in the Enallagma species accounting for it showing the highest bacterial richness and accounting for a sample-wide pattern of more single-species ZOTUs than expected, based on comparisons to the null model. Future studies should address the extent to which faecal bacteria represent non-incidental gut bacteria and whether abundant and shared taxa are true gut symbionts. Pictures of odonates adopted from Norske Art databank under Creative Commons License (CC BY 4.0).

from Fiji (Odonata: Coenagrionidae)

Nikoulabasis roseosticta sp. nov. (holotype , Fiji, Vanua Levu Island, Navuturerega creek, 6 August 2009, Christopher Beatty leg.) is erected as a new taxon. Illustrations of key characters and a distribution map are provided.

Single syntypes of Somatochlora exuberata Bartenev, 1910 (Odonata: Corduliidae), discovered in both the Milwaukee Public Museum and the University of Michigan Museum of Zoology, U.S.A., with designation of the lectotype

A male syntype of Somatochlora exuberata Bartenev, 1910, from Kavykuchi Gazimurskie village, Transbaikalia, Siberia, June 24 (in Julian Calendar, July 7 in Gregorian Calendar) 1909, was discovered in the Milwaukee Public Museum, Wisconsin, U.S.A., as received in exchange from A.N. Bartenev by Richard Anthony Muttkowski. Another male syntype with the same data later was found in the University of Michigan Museum of Zoology, Michigan, U.S.A. The latter specimen is designated as the lectotype of S. exuberata. The description of Somatochlora vera Bartenev, 1914, a name currently considered a junior synonym of S. exuberata, is critically evaluated.

Description of the Last Instar Larva of Platylestes platystylus (Rambur, 1842) from Kerala, India (Odonata: Lestidae)

The description of the final instar larva and the subsequent exuvia of Platylestes platystylus (Rambur, 1842) is given based on a single male larva collected from Kerala and reared in the laboratory. A brief account of the habitat of the damselfly and an updated key to the larvae of genera of Family Lestidae Calvert, 1901 are also provided.

Survey of the Prosthogonimus spp. metacercariae infection in the second intermediate host dragonfly in Heilongjiang Province, China

Prosthogonimiasis poses a threat to the reproductive system of poultry and wild birds, which are the definitive hosts of the parasite causing this disease. However, the parasite infection of the second intermediate host (dragonfly), the primary vector of this pathogen, is rarely reported. In this study, the prevalence of Prosthogonimus infection in dragonflies was investigated from June 2019 to October 2022 in Heilongjiang Province, northeast China. The species of metacercariae isolated from dragonfly were identified by morphological characteristics, molecular biology techniques, and animal infection experiments. The results showed that 11 species of dragonflies and one damselfly were identified and among six of the dragonflies infected by Prosthogonimus metacercariae, Sympetrum depressiusculum (28.53%) had the highest infection rate among all positive dragonflies, followed by Sympetrum vulgatum (27.86%) and Sympetrum frequens (20.99%), which are preferred hosts, and the total prevalence was 20.39% (2061/10,110) in Heilongjiang Province. Three species of Prosthogoniumus metacercariae were isolated, including Prosthogonimus cuneatus, Prosthogonimus pullucidus, and Prosthogonimus sp., among which P. cuneatus was the dominant species in dragonflies in Heilongjiang Province. This is the first report on the prevalence of Prosthogonimus in dragonflies in China, which provides baseline data for the control of prosthogonimiasis in Heilongjiang Province and a reference for the prevention of prosthogonimiasis in other areas of China.

Predation and competition drive trait diversity across space and time

Competition should play a key role in shaping community assembly and thereby local and regional biodiversity patterns. However, identifying its relative importance and effects in natural communities is challenging because theory suggests that competition can lead to different and even opposing patterns depending on the underlying mechanisms. Here, we have taken a different approach: rather than attempting to indirectly infer competition from diversity patterns, we compared trait diversity patterns in odonate (dragonfly and damselfly) communities across different spatial and temporal scales along a natural competition-predation gradient. At the local scale (within a community), we found that trait diversity increased with the size of top predators (from invertebrates to fish). This relationship is consistent with differences in taxonomic diversity, suggesting that competition reduces local trait diversity through competitive exclusion. Spatial (across communities) and temporal (within communities over time) trait variation peaked in communities with intermediate predators indicating that both high levels of competition or predation select for trait convergence of communities. This indicates that competition acts as a deterministic force that reduces trait diversity at the local, regional, and temporal scales, which contrasts with patterns at the taxonomic level. Overall, results from this natural experiment reveal how competition and predation interact to shape biodiversity patterns in natural communities across spatial and temporal scales and provide new insights into the underlying mechanisms.

Revision of &lt;em&gt;Sinomesuropetala daohugensis&lt;/em&gt; Boudet, Nel &amp; Huang, 2023 (Odonata: Aeshnoptera: Mesuropetalidae)

The mesuropetalid dragonfly Sinomesuropetala daohugensis Boudet, Nel & Huang, 2023, is here revised based on a new well-preserved dragonfly from the Haifanggou Formation of Inner Mongolia, northeastern China. The new specimen allows us to complete the forewing characters of this species, showing the close relationship of Sinomesuropetala Boudet, Nel & Huang, 2023 with Mesuropetala Handlirsch, 1906. The mesuropetalid dragonflies are currently recorded from the Late Jurassic and Lower Cretaceous deposits of east Asia, East Central South Europe, and southern America, indicating the wide distribution and the possible long-distance migration ability of some basal aeshnopteran dragonflies during these epochs.

A new species of Minagrion Santos, 1965 (Odonata: Coenagrionidae) from the Cerrado of Northern Minas Gerais state, Brazil

Minagrion veredae sp. nov. (Holotype , BRAZIL (Z329), Minas Gerais state, Grande Serto Veredas National Park, 15.iv.2023, (156 S, 4548 W, 660 to 900m asl), P.S. Vital leg.) is described, illustrated and diagnosed based on specimens collected at the Grande Serto Veredas National Park. The new species inhabits palm swamp environments, Cerrado domain phytophysiognomy, as it is typical of other species of the genus. It can be diagnosed from its congeners mainly by the forcipate shape and large teeth of the cercus and the lanceolate shape of segment two of the genital ligula.

Fatty-acid based assessment of benthic food-web responses to multiple stressors in a large river system

Rivers are often exposed to multiple stressors, such as nutrients and contaminants, whose impacts on the river food webs may not be distinguished by sole assessment of biological community structures. We examined the benthic algal assemblages and the fatty acids (FA) of benthic macroinvertebrates in the lower Athabasca River in Canada, aiming to assess the changes in algal support and nutritional quality of the benthic food web in response to cumulative exposure to natural bitumen, municipal sewage discharge (hereafter, "sewage"), and oil sands mining ("mining"). Data show that the decline in water quality (increases in nutrient concentrations and total suspended solids) was associated with decreases in benthic diatom abundance, and was driven mainly by sewage-induced nutrient enrichment. Responses in nutritional quality of benthic macroinvertebrates, indicated by their polyunsaturated FA (PUFA) concentrations, were taxon- and stressor-specific. Nutritional quality of the larval dragonfly predator, Ophiogomphus, decreased nonlinearly with decreasing benthic diatom abundance and was lowest at the sewage-affected sites, although exposure to natural bitumen also resulted in reduced Ophiogomphus PUFA concentrations. In contrast, the PUFA concentrations of mayfly grazers/collector-gatherers were not affected by natural bitumen exposure, and were higher at the sewage and sewage+mining sites. The PUFA concentrations of the shredder Pteronarcys larvae did not change with cumulative exposure to the stressors. Sediment metal and polycyclic aromatic compound concentrations were not associated with the macroinvertebrate FA changes. Overall, we provide evidence that sewage induced reduction in trophic support by PUFA-rich diatoms, and was the predominant driver of the observed changes in FA composition and nutritional quality of the benthic macroinvertebrates. Fatty-acid metrics are useful to untangle effects of concurrent stressors, but the assessment outcomes depend on the functional feeding guilds used. A food-web perspective using multiple trophic levels and feeding guilds supports a more holistic assessment of the stressor impacts.

Broad-Scale Assessment of Methylmercury in Adult Amphibians

Mercury (Hg) is a toxic contaminant that has been mobilized and distributed worldwide and is a threat to many wildlife species. Amphibians are facing unprecedented global declines due to many threats including contaminants. While the biphasic life history of many amphibians creates a potential nexus for methylmercury (MeHg) exposure in aquatic habitats and subsequent health effects, the broad-scale distribution of MeHg exposure in amphibians remains unknown. We used nonlethal sampling to assess MeHg bioaccumulation in 3,241 juvenile and adult amphibians during 2017-2021. We sampled 26 populations (14 species) across 11 states in the United States, including several imperiled species that could not have been sampled by traditional lethal methods. We examined whether life history traits of species and whether the concentration of total mercury in sediment or dragonflies could be used as indicators of MeHg bioaccumulation in amphibians. Methylmercury contamination was widespread, with a 33-fold difference in concentrations across sites. Variation among years and clustered subsites was less than variation across sites. Life history characteristics such as size, sex, and whether the amphibian was a frog, toad, newt, or other salamander were the factors most strongly associated with bioaccumulation. Total Hg in dragonflies was a reliable indicator of bioaccumulation of MeHg in amphibians (R2 ≥ 0.67), whereas total Hg in sediment was not (R2 ≤ 0.04). Our study, the largest broad-scale assessment of MeHg bioaccumulation in amphibians, highlights methodological advances that allow for nonlethal sampling of rare species and reveals immense variation among species, life histories, and sites. Our findings can help identify sensitive populations and provide environmentally relevant concentrations for future studies to better quantify the potential threats of MeHg to amphibians.

Influence of the World Athletics Stack Height Regulation on Track Running Performance

ABSTRACT

Ruiz-Alias, SA, Pérez-Castilla, A, Soto-Hermoso, VM, and García-Pinillos, F. Influence of the world athletics stack height regulation on track running performance. J Strength Cond Res 37(11): 2260-2266, 2023-A new footwear regulation based on limiting the stack height (i.e., amount of material between the feet and the ground) has been established by World Athletics to ensure that performance is achieved through the primacy of human effort over technology in running shoes. Analyzing the effect of legal and illegal shoes on running performance is therefore needed to determine its effectiveness. Thus, this study aimed (a) to compare the effect of 2 footwear models categorized as legal and illegal by the World Athletics regulation on track running performance and (b) to analyze the derived metrics of the athletes' biomechanics when using each footwear model at racing paces. Within 1 week, 14 highly trained athletes performed 2 testing sessions composed of 2 time trials of 9- and 3-minute duration with 30 minutes of recovery between them. The athletes wore the "Nike ZoomX Dragonfly" track spikes model and the "Nike ZoomX Vaporfly Next % 2" marathon shoe model in a counterbalanced randomized order. The results revealed that (a) there was only a small worthwhile improvement in the 3-minute time trial when using the marathon shoes of 0.97% (-0.04 to 1.98%) and (b) there was a main effect of footwear in 7 of the 9 biomechanical variables analyzed (p ≤ 0.050). The ground contact time was the unique performance predictor (p = 0.005, adjusted R2 = 0.476). Altogether, the use of legal and illegal running shoes altered the runners form, which only influenced the mid-distance performance.

Descriptions of the last instar larvae of Anotogaster chaoi Zhou, 1998 and Neallogaster annandalei (Fraser, 1923) from Erhai Lake Basin, Yunnan, China (Odonata: Cordulegastrids)

The exuviae of Anotogaster chaoi Zhou, 1998 and Neallogaster annandalei (Fraser, 1923) are described and illustrated for the first time from Erhai Lake Basin, Yunnan Province, China, based on the final stage larvae reared in a laboratory. Diagnostic differences between the larvae of congeneric A. chaoi, A. gregoryi Fraser, 1923, as well as N. annandalei and N. hermionae (Fraser, 1927) are discussed, and notes on their habitats are provided.

Taxonomic revision of the Neotropical genus Heteragrion Selys, 1862 (Zygoptera: Heteragrionidae): male morphology, new species and illustrated key

In this study, we have comprehensively presented taxonomic information on all 62 known species of Heteragrion Selys, 1862, which includes illustrations, photographs, diagnostic characters, and a key to males. Our analysis is based on the examination of over 900 specimens from 19 different collections worldwide, encompassing the type material for at least 42 species. Furthermore, we have described a new species, Heteragrion corderoi sp. nov. (, BRAZIL, So Paulo state, Campos do Jordo, Condomnio Paradise, 24.i.1999, (Coordinates: -22.7072, -45.5894, 1796 m asl), F.A.A. Lencioni leg., LABECO), which we identified from a male that was previously considered to be a paratype of H. mantiqueirae Machado, 2006 and additional specimens collected in Campos do Jordo, So Paulo state.

Nomenclatural reconsideration of the genera Aeschnophlebia Selys, 1883 and Planaeschna McLachlan, 1896 (Odonata, Aeshnidae)

The nominal species Aeschna milnei Selys, 1883 and Aeschnophlebia optata Selys, 1883 are considered subjective synonyms, with A. milnei as the valid name based on an act of the First Reviser. Since A. milnei is the type species of Planaeschna McLachlan, 1896, and A. optata is the type species of Aeschnophlebia Selys, 1883 (by subsequent designation), both nominal genera are also subjective synonyms, with Aeschnophlebia as the valid name. Species until recently included in Aeschnophlebia (except the type species), are now considered congeneric with Aeshna vernalis Vander Linden, 1820, the type species of Brachytron Evans, 1845 and a junior subjective synonym of B. pratense (Mller, 1764). The present paper provides the correct combinations and name spellings for all subspecies presently assigned to the genera Planaeschna and Aeschnophlebia.

Effect of predators on Anopheles arabiensis and Anopheles funestus larval survivorship in Homa Bay County Western Kenya

BACKGROUND

The rise of insecticide resistance against malaria vectors in sub-Saharan Africa has resulted in the need to consider other methods of vector control. The potential use of biological methods, including larvivorous fish, Bacillus thuringiensis israelensis (Bti) and plant shading, is sustainable and environmentally friendly options. This study examined the survivorship of Anopheles arabiensis and Anopheles funestus larvae and habitat productivity in four permanent habitat types in Homa Bay county, western Kenya.

METHODS

Predator densities were studied in a laboratory setup while habitat productivity and larval survivorship was studied in field setup.

RESULTS

Fish were observed as the most efficient predator (75.8% larval reduction rate) followed by water boatman (69%), and dragonfly nymph (69.5%) in predation rates. Lower predation rates were observed in backswimmers (31%), water beetles (14.9%), water spiders (12.2%), mayflies (7.3%), and tadpoles (6.9%). Increase in predator density in the field setup resulted in decreased Culex larval density. Larval and pupa age-specific distribution was determined and their survivorship curves constructed. Combined larvae (Stage I-IV) to pupa mortality was over 97% for An. arabiensis and 100% for An. funestus. The highest larval stage survival rate was from larval stages I to II and the lowest from larval stage IV to pupa. Stage-specific life tables indicated high mortality rates at every developmental stage, especially at the larval stage II and III.

CONCLUSION

Determination of the efficiency of various larval predators and habitat productivity will help with the correct identification of productive habitats and selection of complementary vector control methods through environmental management and/or predator introduction (for instance fish) in the habitats.

(Odonata: Zygoptera: Platystictidae) from Samtse district, Bhutan

Protosticta samtsensis sp. nov. (holotype : Bhutan, Samtse District, Norgaygang gewog (Bara), 27.142670N, 88.835228E; altitude 1,264 m, 12-viii-2022), is described from a holotype male and a female paratype and compared with P. himalaica Laidlaw, 1917.

Biomimetic Compound Eyes with Gradient Ommatidium Arrays

Compound eyes are high-performing natural optical perception systems with compact configurations, generating extensive research interest. Existing compound eye systems are often combinations of simple uniform microlens arrays; there are still challenges in making more ommatidia on the compound eye surface to focus to the same plane. Here, a biomimetic gradient compound eye is presented by artificially mimicking dragonflies. The multiple replication process efficiently endows compound eyes with the gradient characteristics of dragonfly compound eyes. Experimental results show that the manufactured compound eye allows multifocus imaging by virtue of the gradient ommatidium array arranged closely in a honeycomb pattern while ensuring excellent optical properties and compact configurations. Thousands of ommatidia showing a gradient trend at the millimeter scale while remaining relatively uniform at the micron scale have gradient focal lengths ranging from 260 to 450 μm. This gradient compound eye allows more ommatidia to focus on the same plane than traditional uniform compound eyes, which have experimentally been shown to capture more than 1100 in-plane clear images simultaneously, promising potential applications in micro-optical devices, optical imaging, and biochemical sensing.

Climate change as a driver of insect invasions: Dispersal patterns of a dragonfly species colonizing a new region

The dragonfly Trithemis kirbyi Sélys, 1891 recently colonized Western Europe from North Africa. Since its first record in the Iberian Peninsula in 2007, the species has been spreading northward and has become naturally established in the central and eastern Iberian Peninsula, the Balearic Islands and southern France. Despite its worldwide distribution, its rapid colonization of the western Mediterranean area occurred only very recently. The aims of this study were to evaluate (1) whether the species' colonization of the western Mediterranean is related to climate change and rising temperatures, specifically the summer warming peaks that have occurred in the last decade, (2) which climatic variables have most influenced its distribution and dispersal, and (3) its potential future dispersal and colonization capacity towards the eastern Mediterranean. We found that the dispersal and recent establishment of T. kirbyi in southwestern Europe strongly depends on increasing temperatures, particularly summer temperature peaks, which has allowed this species to disperse farther and more effectively than during years with average summer temperatures. The most important variable in the suitability models is the minimum temperature of the coldest month, which, in recent decades, has become less of a limiting factor for ectotherms. According to the models, suitable areas for the species are currently found throughout the eastern Mediterranean parts of Europe, and it is likely that it can naturally colonize these areas as it did in the Iberian Peninsula. Trithemis kirbyi is a model of how climate change and observed rising temperatures have turned previously inhospitable regions into suitable areas for exotic species, which may successfully colonize them naturally if they can reach these promising lands on their own. However, this study serves as a warning that such species can also colonize these new regions with a little help from unsuspecting means, which are often responsible for the increasingly common presence of invasive, noxious taxa in Europe.

(Odonata: Coenagrionidae: Protoneurinae) from Amazonian Ecuador

Epipleoneura parmula sp. nov. is described and illustrated based on males from eastern Ecuador (holotype: , ECUADOR, Orellana Province, Primavera, Laguna Taracoa {0.4652S, 76.7638W}, 247 m, 27 July 1977, Dennis R. Paulson & Susan Hills leg., in FSCA). Using the most recent synopsis of the genus (Pessacq 2014), the new species keys to the couplet separating E. pallida Rcenis and E. ocuene De Marmels, but unlike in those species, the epiproct branches are longer, fused nearly their entire length and their tips are accentuated. Adults were collected at a lake and several ponds, indicating that the habitat is lentic, although the nymph is unknown.

Three dimensional structures of the inner and outer pig petrous bone using FIB-SEM: Implications for development and ancient DNA preservation

We report on the 3D ultrastructure of the mineralized petrous bone of mature pig using focused ion beam - scanning electron microscopy (FIB-SEM). We divide the petrous bone into two zones based on the degree of mineralization; one zone close to the otic chamber has higher mineral density than the second zone further away from the otic chamber. The hypermineralization of the petrous bone results in the collagen D-banding being poorly revealed in the lower mineral density zone (LMD), and absent in the high mineral density zone (HMD). We therefore could not use D-banding to decipher the 3D structure of the collagen assembly. Instead we exploited the anisotropy option in the Dragonfly image processing software to visualize the less mineralized collagen fibrils and/or nanopores that surround the more mineralized zones known as tesselles. This approach therefore indirectly tracks the orientations of the collagen fibrils in the matrix itself. We show that the HMD bone has a structure similar to that of woven bone, and the LMD is composed of lamellar bone with a plywood-like structural motif. This agrees with the fact that the bone close to the otic chamber is fetal bone and is not remodeled. The lamellar structure of the bone further away from the otic chamber is consistent with modeling/remodeling. The absence of the less mineralized collagen fibrils and nanopores resulting from the confluence of the mineral tesselles may contribute to shielding DNA during diagenesis. We show that anisotropy evaluation of the less mineralized collagen fibrils could be a useful tool to analyze bone ultrastructures and in particular the directionality of collagen fibril bundles that make up the bone matrix.

Bioinspired bi-phasic 3D nanoflowers of MgO/Mg(OH)2 coated melamine sponge as a novel bactericidal agent

By roughly mimicking the surface architectural design of dragonfly wings, novel bi-phasic 3D nanoflowers of MgO/Mg(OH)2 were successfully synthesized via the electrospinning technique. The 3D nanoflowers were coated over a commercial melamine sponge and extensively characterized by SEM, XRD, FTIR, and EDS. The formation of distinct dense 3D nano petals was revealed by SEM images whereby the mean petal thickness and mean distance between the adjacent petals were found to be 36 nm and 121 nm, respectively. The bactericidal activities of synthesized 3D nano-flowers coated melamine sponges were assessed against five different bacteria (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa). This study demonstrated significant bactericidal activity of MgO/Mg(OH)2 3D nanoflowers coated MS against Gram-positive and Gram-negative bacteria. Plausible bactericidal mechanisms include envelope deformation, penetration, and induction of oxidative stress. This study introduces novel bioinspired biomaterial with the capacity to reduce the risk associated with pathogenic bacterial infections, especially in medical devices.

A Year at the Forefront of Gliding Locomotion

This review highlights the largely understudied behavior of gliding locomotion, which is exhibited by a diverse range of animals spanning vertebrates and invertebrates, in air and in water. The insights in the literature gained from January 2022 to December 2022 continue to challenge the previously held notion of gliding as a relatively simple form of locomotion. Using advances in field/lab data collection and computation, the highlighted studies cover gliding in animals including seabirds, flying lizards, flying snakes, geckos, dragonflies, damselflies, and dolphins. Altogether, these studies present gliding as a sophisticated behavior resulting from the interdependent aspects of morphology, sensing, environment, and likely selective pressures. This review uses these insights as inspiration to encourage researchers to revisit gliding locomotion, both in the animal's natural habitat and in the laboratory, and to investigate questions spanning gliding biomechanics, ecology, sensing, and the evolution of animal flight.

Effects of heat and pesticide stress on life history, physiology and the gut microbiome of two congeneric damselflies that differ in stressor tolerance

The combined impact of toxicants and warming on organisms is getting increased attention in ecotoxicology, but is still hard to predict, especially with regard to heat waves. Recent studies suggested that the gut microbiome may provide mechanistic insights into the single and combined stressor effects on their host. We therefore investigated effects of sequential exposure to a heat spike and a pesticide on both the phenotype (life history and physiology) and the gut microbiome composition of damselfly larvae. We compared the fast-paced Ischnura pumilio, which is more tolerant to both stressors, with the slow-paced I. elegans, to obtain mechanistic insights into species-specific stressor effects. The two species differed in gut microbiome composition, potentially contributing to their pace-of-life differences. Intriguingly, there was a general resemblance between the stressor response patterns in the phenotype and in the gut microbiome, whereby both species responded broadly similar to the single and combined stressors. The heat spike negatively affected the life history of both species (increased mortality, reduced growth rate), which could be explained not only by shared negative effects on physiology (inhibition of acetylcholinesterase, increase of malondialdehyde), but also by shared effects on gut bacterial species' abundances. The pesticide only had negative effects (reduced growth rate, reduced net energy budget) in I. elegans. The pesticide generated shifts in the bacterial community composition (e.g. increased abundance of Sphaerotilus and Enterobacteriaceae in the gut microbiome of I. pumilio), which potentially contributed to the relatively higher pesticide tolerance of I. pumilio. Moreover, in line with the response patterns in the host phenotype, the effects of the heat spike and the pesticide on the gut microbiome were mainly additive. By contrasting two species differing in stress tolerance, our results suggest that response patterns in the gut microbiome may improve our mechanistic understanding of single and combined stressor effects.

Adverse effects of the pesticide chlorpyrifos on the physiology of a damselfly only occur at the cold and hot extremes of a temperature gradient

Ecotoxicological studies considerably improved realism by assessing the toxicity of pollutants at different temperatures. Nevertheless, they may miss key interaction patterns between pollutants and temperature by typically considering only part of the natural thermal gradient experienced by species and ignoring daily temperature fluctuations (DTF). We therefore tested in a common garden laboratory experiment the effects of the pesticide chlorpyrifos across a range of mean temperatures and DTF on physiological traits (related to oxidative stress and bioenergetics) in low- and high-latitude populations of Ischnura elegans damselfly larvae. As expected, the impact of chlorpyrifos varied along the wide range of mean temperatures (12-34 °C). None of the physiological traits (except the superoxide anion levels) were affected by chlorpyrifos at the intermediate mean temperatures (20-24 °C). Instead, most of them were negatively affected by chlorpyrifos (reduced activity levels of the antioxidant defense enzymes superoxide dismutase [SOD], catalase [CAT] and peroxidase [PER], and a reduced energy budget) at the very high (≥28 °C) or extreme high temperatures (≥32 °C), and to lesser extent at the lower mean temperatures (≤16 °C). Notably, at the lower mean temperatures the negative impact of chlorpyrifos was often only present or stronger under DTF. Although the chlorpyrifos effects on the physiological traits greatly depended on the experimentally imposed thermal gradient, patterns were mainly consistent across the natural latitude-associated thermal gradient, indicating the generality of our results. The thermal patterns in chlorpyrifos-induced physiological responses contributed to the observed toxicity patterns in life history (reduced survival and growth at low and high mean temperatures). Taken together, our results underscore the importance of evaluating pesticide toxicity along a temperature gradient and of taking a mechanistic approach with a focus on physiology, to improve our understanding of the combined effects of pollutants and temperature in natural populations.

(Odonata, Zygoptera) from the early Eocene Fur Formation of Denmark and the dysagrionoid grade

The earliest Eocene odonate genus Furagrion Petrulevičius et al. from the Danish Fur Formation is revised based on eighteen specimens, two of which apparently have been lost since their publication. The holotype of Phenacolestes jutlandicus Henriksen, type species of Furagrion, is incomplete and lacks the characters currently used to differentiate species, genera and higher taxa in Odonata. We, therefore, propose that the holotype is set aside and a recently discovered nearly complete Fur Formation fossil is designated as neotype. Furagrion possesses all of the nine wing character states currently used along with head shape for diagnosing the Dysagrionidae; however, Furagrion has a characteristically zygopteran head, not the distinctive head shape of the suborder Cephalozygoptera. We, therefore, treat it as a zygopteran unassigned to family. These nine wing character states appear in different combinations not only in various Zygoptera and Cephalozygoptera, but also in the Frenguelliidae, an Eocene family of Argentina that may represent an unnamed suborder. We recognise these taxa as constituting a dysagrionoid grade, in which these character states appear either convergently or as symplesiomorphies. Furagrion morsi Zessin is synonymized with Phenacolestes jutlandicus Henriksen, syn. nov. and Morsagrion Zessin with Furagrion Petrulevičius, Wappler, Wedmann, Rust, and Nel, syn. nov.

The influence of short-term temporal variability on the efficacy of dragonfly larvae as mercury biosentinels

Mercury (Hg) exposure to fish, wildlife, and humans is widespread and of global concern, thus stimulating efforts to reduce emissions. Because the relationships between rates of inorganic Hg loading, methylmercury (MeHg) production, and bioaccumulation are extremely complex and challenging to predict, there is a need for reliable biosentinels to understand the distribution of Hg in the environment and monitor the effectiveness of reduction efforts. However, it is important to assess how temporal and spatial variation at multiple scales influences the efficacy of specific biosentinels. Seasonal and interannual variation in total Hg (THg) concentrations of dragonfly larvae were examined in relation to spatial variability among 21 sites in two U.S. national parks with contrasting ecologies and Hg deposition patterns. Dragonfly THg differed among sampling events at 17 of the 21 sites, but by an average of only 20.4 % across events, compared to an average difference of 52.7 % among sites. Further, THg concentrations did not follow consistent seasonal patterns across sites or years, suggesting that the observed temporal variation was unlikely to bias monitoring efforts. Importantly, for a specific site, there was no difference in % MeHg in dragonflies among sampling events. Finally, there was significant temporal variability in the biogeochemical factors (aqueous inorganic Hg, aqueous MeHg, DOC, SO₄, and pH) influencing dragonfly THg, with the importance of individual factors varying by 2.4 to 4.3-fold across sampling events. Despite these results, it is noteworthy that the observed temporal variation in dragonfly THg concentrations was neither large nor consistent enough to bias spatial assessments. Thus, although this temporal variation may provide insights into the processes influencing biological Hg concentrations, it is unlikely to impair the use of dragonflies as biosentinels for monitoring spatial or temporal patterns at scales relevant to most mitigation efforts.