Search Results (1,403)

Galeruca daurica (Joannis) (Coleoptera: Chrysomelidae) is an oligophagous pest in which both adults and larvae prefer to feed on Allium forage grasses of the Liliaceae family. In this study, we identified gustatory receptor (GR) genes based on the transcriptome data of G. daurica; analyzed the expression profiles of these GR genes across different larval instars and various tissues of male and female adults using quantitative real-time PCR (qRT-PCR); detected the electrophysiological responses of the mouthparts of male and female G. daurica adults to flavonoids and carbohydrates using single sensillum recording (SSR); and recorded the changes in food consumption of G. daurica adults after feeding on six host plant-derived metabolites. A total of 26 GR genes were identified from the transcriptome data of adult and larval of G. daurica. Phylogenetic analysis was performed to screen candidate functional gustatory receptor genes, including four sugar receptors (GdauGR7, GdauGR10, GdauGR14 and GdauGR28), seven bitter receptors (GdauGR11, GdauGR16~17, GdauGR22, GdauGR25~26 and GdauGR30), and two CO₂ receptors (GdauGR15 and GdauGR20). Larval expression profiling of GdauGRs in G. daurica revealed that the relative expression levels of 17 genes exhibited dynamic changes during larval growth and development. GdauGRs were expressed to varying degrees in the antennae, mouthparts, brain, gut, and forelegs of adult G. daurica, with sex-specific differences. Notably, the expression levels of GdauGR4, GdauGR9 and GdauGR16 in the gut were extremely significantly higher than those in other tissues. In the SSR test, the six tested flavonoids and one carbohydrate were able to induce robust electrophysiological responses in the gustatory sensilla on the antennae and mouthparts of adult G. daurica at specific concentrations. In addition, the supplementation of several host-derived metabolites altered the food consumption of adult G. daurica. These findings lay a solid foundation for elucidating the molecular mechanisms underlying gustatory recognition and host adaptation in G. daurica. Full article

Dryopidae (Insecta: Coleoptera) comprise 37 genera and about 280 species, occurring on all continents except Antarctica. The Neotropical fauna of the family has been neglected for decades, despite a few recent contributions. So far, seven genera and 29 species have been recorded from Brazil. Based on 369 adults collected in the Brazilian states of Bahia, Paraná, and Rio de Janeiro, we describe Dryops antonioi sp. nov., D. nelsimarae sp. nov., and D. simoneae sp. nov. Furthermore, we herein redescribe and provide new records for D. ovatus (Grouvelle, 1890), an updated key to the species recorded from the country and a checklist of Neotropical representatives of the genus. Full article

Growing interest in environmentally compatible stored-product pest control has highlighted diatomaceous earth (DE) and 1,8-cineole as promising agents, both alone and in combination. Their different modes of action, together with the limitations associated with higher-dose single applications, support evaluating their combined use at lower doses. This study was conducted to compare the effects of DE and 1,8-cineole, applied alone and in combination, on the larval, pupal, and adult stages of Tenebrio molitor. Five different concentrations were tested for each substance (DE at 25, 50, 100, 250, and 500 ppm, and 1,8-cineole at 2.5, 5, 10, 15, and 20 ppm), and four DE + 1,8-cineole combinations were evaluated within the same experimental system. Mortality was monitored over time, LC₅₀ values were calculated by probit analysis, and larval output observed after adult treatments was also evaluated. The findings indicated that the biological response was associated with developmental stage. The lowest LC₅₀ for DE was recorded in larvae at 86.11 ppm on day 3, whereas for 1,8-cineole the lowest LC₅₀ was recorded in adults at 94.83 ppm on day 3. Combined treatments generally tended to produce faster and stronger mortality; in particular, the DE250 + CIN20 treatment reached 100% mortality in larvae and adults and 93.33% mortality in pupae by day 7. In addition, larval output decreased in the single-treatment groups, the proportion of dead larvae among the observed larvae increased to 96–100%, and no larval output was detected in the combination groups. Combinations of DE and 1,8-cineole tended to produce more pronounced mortality responses than the single treatments, particularly in the larval and adult stages. The present findings indicate that combining DE with 1,8-cineole may provide a promising stage-specific strategy for improving the control of T. molitor under laboratory conditions. Full article

Background/Objectives: Cyto-nuclear discordances, resulting from the independent evolutionary histories of cytoplasmic and nuclear genomes, often obscure phylogenetic inference and species delimitation, particularly at shallow taxonomic levels. In this study, we examine the extent and causes of cyto-nuclear discordances within the darkling beetle tribe Akidini (Coleoptera: Tenebrionidae), focusing on the genera Akis Herbst, 1799 and Morica Dejean, 1834. Methods: Using two molecular markers—nuclear histone 3 (H3) and mitochondrial cytochrome c oxidase subunit I (COI)—and a comprehensive sampling from western Europe and northern Africa, we assess reciprocal monophyly, internal relationships, and phylogenetic incongruence across datasets. Results: Discordances between morphological species assignment and mitochondrial topologies may result from retained ancient polymorphisms or historical introgression among closely related species (e.g., Akis genei vs. Akis lusitanica). However, these causes seem less plausible for explaining discordances between nuclear and mitochondrial markers involving non-closely related species (e.g., A. discoidea and A. granulifera). The geographic location of the problematic specimens, limited to a narrow marginal contact zone between the two non-sister species, suggests that local hybridisation may occur. Conclusions: Our results indicate that cyto-nuclear discordances between mitochondrial and nuclear markers, even across morphologically well-differentiated non-sister lineages, may be more frequent than previously assumed in darkling beetles, highlighting both their evolutionary relevance and the need for caution when relying solely on mitochondrial data for species identification. Full article

This study contributes to the taxonomic research on the “Prionus gahani” species group, which includes six species. A new species, Prionus zhumingyui Lin & Drumont, sp. nov., is described from Guangdong Province, China. The new species is distinguished by having pronotum longer, antennomere III with obvious apical lobe more stretched outward and cone-shaped. Illustrations of the habitus and genitalia of the new species and other four species are provided. The habitats and collecting experiences of four species are provided: P. zhumingyui Lin & Drumont, sp. nov., P. sontinh Do, Drumont & Komiya, 2019 (with new locality information), P. antonkozlovi Drumont & Komiya, 2021, and P. gahani Lameere, 1912 (with female described for the first time). It is concluded that the species of this group are diurnal, although they have somber colors. Their small compound eyes (especially compared with other Prionus species, which have large compound eyes and are attracted to light) are well-matched to their diurnal lifestyle. Full article

Recent work demonstrated that Cicindelidia hemorrhagica (LeConte) inhabiting geothermal springs in Yellowstone National Park (YNP) possess morphological traits that reduce internal heat load when exposed to bottom-up thermal stress. To investigate whether this pattern extends to other tiger beetle species occupying diverse environments, we quantified the internal abdominal temperatures of six species differing in habitat preference and putative thermal adaptation. Using a water-bath system that simulated surface heating, we compared the temperature differential (ΔT) between beetle-loaded and bare thermocouples across multiple temperatures. Linear mixed-effects models were used to evaluate the influence of location and species on internal temperature. Across all experimental temperatures, C. hemorrhagica exhibited the greatest ΔT values, indicating the lowest internal temperatures relative to the thermal environment, regardless of whether individuals originated from YNP or non-thermal Idaho habitats. In contrast, the warm-resilient Cicindela repanda (Dejean) and non-warm-adapted C. longilabris (Say) showed the smallest ΔT values and therefore the highest internal temperatures. Ventral abdominal coloration—ranging from bright red (C. sedecimpunctata (Klug)) to dark blue-green (C. oregona (Dejean))—did not correlate with internal temperatures, suggesting that it is a poor predictor of heat absorbance or reflectance under bottom-up heat exposure. These results indicate that C. hemorrhagica is uniquely effective at limiting internal heat gain from surface heating, and that it may possess a preadaptive morphological mechanism facilitating thermal resistance in geothermal habitats. Full article

Soldier beetle larvae are characterised by numerous very small setae on their body surface, giving them a velvety appearance and hydrophobic properties, and paired gland openings on the segments of the thorax and abdomen for defensive purposes. Only recently, such a larva has been recognised in Cretaceous amber. Previously, only two specimens from Baltic amber were known from the fossil record. This provides the impression that such larvae are rare. We report 45 new larval specimens from Eocene Baltic amber and Cretaceous Kachin amber (Myanmar), demonstrating that these fossils are, in fact, more common, but simply not reported. We use the expanded dataset (with fossil and extant larvae and adults, more than 300 specimens) to explore the ontogeny of soldier beetles by quantitatively comparing morphological aspects over time. It appears that there is no major loss in the morphology of adults and larvae. On the contrary, certain larvae known in the modern fauna, so-called pre-larvae, seem absent in the fossil record. Due to the pre-larvae, some modern soldier beetles have certain characteristics of hypermetamorphosis. This type of developmental pattern is also characterised by a distinct change in the direction of the developmental trajectory. However, such a change could not be identified in soldier beetles. Full article

Anomala corpulenta (Motschulsky, 1854) (Coleoptera: Scarabaeidae), an important agricultural and forestry pest, is a beetle widely distributed in many countries, inflicting damage on numerous crops. Given the limited selectivity of commonly used light trapping devices for insects and their potential adverse effects on the ecological environment, there is a pressing need for innovative light control methods. This study investigates the effects of continuous exposure to yellow light on the behavioral activities of A. corpulenta adults, which are nocturnal. The experimental setup comprised a light experimental group (exposed continuously to yellow light at wavelengths of 565–585 nm and intensities of 30–40 lx at night) and a control group (kept in a dark room). Observations were made on emergence, mating, feeding, and mortality. Results showed that continuous exposure to yellow light significantly alters the emergence rhythm of A. corpulenta, leading to delays and dispersions in peak emergence, with emergence occurring during the light period. The emergence rates varied significantly from the control group during specific periods, and the overall emergence rate was notably affected, with female insects exhibiting greater sensitivity. Furthermore, food consumption and the number of mating pairs were significantly lower compared to the control group. Continuous exposure to yellow light also influenced the longevity of A. corpulenta; in the mixed test group, female insects had a lifespan of 20 days, while males lived for 18 days. In the sexually isolated test group, both sexes died within 16 days, with the survival rates of the experimental group being lower than those of the control group on certain days. This study concludes that continuous exposure to yellow light significantly modifies the emergence rhythm of A. corpulenta, while reducing the emergence rate, total food intake, and the number of mating pairs. Notably, in the mixed-sex test group, the survival probability of females in the experimental group was significantly lower than that of the control group. These findings provide a theoretical foundation for the light control of A. corpulenta and contribute to the field of insect visual ecology. Full article

Water scavenger beetles (Coleoptera: Hydrophiloidea) exhibit remarkable adaptations to both aquatic and terrestrial habitats and play irreplaceable ecological roles, yet their higher-level phylogeny and the molecular basis of their adaptive evolution remain unresolved. Here, we sequenced four complete mitogenomes of C. unipunctatus from the Qinghai–Tibetan Plateau (QTP) and conducted a comprehensive mitogenomic analysis by integrating these new data with 22 publicly available Hydrophiloidea mitogenomes, representing three families and six subfamilies. Our analyses revealed highly conserved mitogenomic architecture across Hydrophiloidea, with structural variation confined to non-coding regions and AT content correlating with both habitat type and phylogenetic lineage. Phylogenetic reconstructions robustly resolved the higher-level relationships: Helophoridae and Hydrochidae formed the sister group to Hydrophilidae, within which Hydrophilinae and Sphaeridiinae were strongly supported as monophyletic clades. We detected positive selection in the energy metabolism genes cox3 and nad5 along the ancestral branch of the terrestrial subfamily Sphaeridiinae, providing the first molecular evidence linking mitochondrial adaptation to the aquatic-to-terrestrial habitat shift. However, no positive selection signals were found in high-altitude C. unipunctatus populations, suggesting that adaptation to extreme environments operates through alternative mechanisms (e.g., regulatory or structural variation) rather than protein-coding evolution. This study establishes a robust phylogenetic framework for Hydrophiloidea and reveals the diverse molecular pathways underlying their adaptive evolution, from protein-coding adaptation during aquatic–terrestrial shifts to non-coding responses in extreme high-altitude environments. Full article

Plastic pollution is ubiquitous in the environment, with microplastics (particles < 5 mm) a worldwide emergent contaminant of concern; however, no studies have explored historical patterns in freshwater macroinvertebrates in connection to species traits and changes in land use. We measured microplastics in macroinvertebrates collected from 1998–2019 at six forest, urban, and agriculture dominated streams in the Schuylkill River watershed (PA, USA). We selected representative macroinvertebrates that underwent peroxide oxidation digestion and were examined for microplastics under a dissecting microscope with Rose Bengal dye to confirm microplastic identification. Microplastics were present in 134 individuals across 24 taxa and all functional feeding groups (FFGs). Abundance of microplastics in macroinvertebrates decreased through time with an increase of agriculture land use, whereas microplastics increased with an increase of urban land use. Collector-gatherer FFG had the greatest microplastic abundance, which may be linked to Elmidae and Psephenidae (Coleoptera), which tended to have the highest abundances of microplastics compared to all other taxa in some years. This relationship may be explained by the feeding mode of these families of macroinvertebrates and that gathering particles in the water column and scraping particles from biofilms may be similarly effective in the acquisition of microplastics. Overall, understanding microplastic temporal patterns and their connections to species traits and variations in land and water use is critical to developing a predictive framework for explaining microplastic abundance in the environment and interactions with aquatic biota. Full article

Spinosad, Saccharopolyspora spinosa, is widely used as a stored product protectant. However, its efficacy against the hide beetle Dermestes maculatus DeGeer (Coleoptera: Dermestidae), a major pest of dried animal-based materials, remains underexplored. In this study, we evaluated the contact and oral toxicities of spinosad across a range of concentrations applied directly to animal-derived substrates. Larval and adult mortality, along with probit parameters, were determined to assess susceptibility. Spinosad produced significant mortality in both life stages, with larvae exhibiting higher susceptibility under contact exposure, whereas adults showed increased susceptibility under feeding exposure. These patterns are consistent with prior reports of spinosad’s dual-action toxicity against stored-product pests. The larval contact and adult feeding exposures to spinosad were positively associated with higher doses, while adult contact and larval food exposures aligned with lower doses. The larval contact and adult ingestion routes drive the strongest toxic responses, whereas adult contact and larval feeding elicit weaker effects under the same doses. Overall, our results highlight spinosad as a promising tool for integrated pest management of hide beetles in animal-based storage systems. Full article

Ips typographus is one of the most destructive bark beetles affecting conifer forests in Europe, where climatic disturbances and the movement of infested wood can rapidly shift populations from endemic levels to severe outbreaks. Early detection through border inspections and forest monitoring is essential to prevent new introductions and limit the spread of established populations. Here, we developed and validated a probe-based TaqMan qPCR assay, targeting the mitochondrial COI barcode region, for the rapid and species-specific detection of I. typographus from both insect material and environmental DNA recovered from frass and exit-hole wood chips. Validation followed EPPO PM7/98(5) guidelines, assessing analytical specificity, sensitivity, repeatability, reproducibility, and inter-laboratory transferability. High analytical specificity was demonstrated against a broad panel of non-target species, and reliable amplification was obtained across different tested matrices. The method showed strong analytical sensitivity, with limits of detection of 0.32 pg/µL for adult-derived DNA and 1.6 pg/µL for artificial frass. Repeatability, reproducibility, and inter-laboratory blind testing further confirmed the diagnostic reliability of the method. This validated qPCR assay provides a rapid and sensitive molecular tool for the early detection of I. typographus, supporting border inspection and phytosanitary diagnostic laboratories in forest biosecurity activities. Full article

Rhynchophorus ferrugineus is a destructive trunk-boring pest of palm plants and exhibits marked polymorphism in adult speckle patterns. This study investigated the genetic basis and molecular mechanisms underlying speckle variation in R. ferrugineus with the aim of identifying key regulatory genes. Integrated genetic analyses and genome-wide association approaches were used to characterize the inheritance and genomic architecture of speckle traits. Pronotum speckle variation was identified as a sex-independent quantitative trait controlled by major loci with additive and dominance effects. Multiple loci and significant quantitative trait nucleotides associated with speckle variation were identified through linkage mapping and association analyses. By integrating genetic mapping results with bioinformatics annotation, three candidate genes, RferTRXR1, RferGH1, and RferLAC2, were identified. Quantitative real-time PCR analysis showed that RferTRXR1 and RferGH1 were more highly expressed in individuals with higher speckle numbers. These findings highlight RferTRXR1 and RferGH1 as potential regulators of speckle pattern variation in R. ferrugineus and provide new insights into the molecular mechanisms underlying phenotypic polymorphism in an important palm pest. Full article

Insects underpin key ecosystem services. Yet tree-associated insect communities remain comparatively poorly documented, particularly in temperate forests. This study aimed to characterize the diversity and abundance of insect assemblages associated with the predominantly insect-pollinated forest tree Tilia cordata Mill. in protected areas in Lithuania, and to assess the occurrence of known and putative pollinator groups within these assemblages. We quantified insect assemblages associated with Tilia cordata using two sampling methods but did not directly measure pollination effectiveness (e.g., pollen loads, visitation rates to flowers, or fruit/seed set). Consequently, our inferences refer to the presence and composition of potential pollinators rather than demonstrated pollination function or realized pollination services. Fieldwork was conducted over two years in six protected T. cordata sites in Lithuania using two complementary sampling methods: net sampling and sticky traps. Sampling was structured into three observation periods corresponding to T. cordata phenology: pre-flowering (I), flowering (II) and post-flowering (III). In total, 207 insect taxa from 15 orders were recorded by net sampling and 86 taxa from 11 orders by sticky traps. Net sampling showed significantly higher diversity (Shannon H = 3.81) than sticky traps (H = 2.10). Hemiptera, Coleoptera and Diptera were the most common groups, and most taxa occurred at low to moderate abundances, with only a few species showing local dominance in specific periods or sites. Taxa documented in the literature as significant pollinators were consistently present but at low relative abundances (about 5–10% in total). Insect assemblage composition and species proportions varied among phenological periods and between years, with no clear, consistent peak in overall insect abundance or diversity associated specifically with the T. cordata flowering phase. These findings indicate that T. cordata stands in protected areas harbor diverse insect assemblages typical of temperate deciduous and mixed forest habitats and include a broad spectrum of non-bees and other potential pollinators. Therefore, we did not detect a distinct peak in insect abundance or species richness during the T. cordata flowering period, indicating that flowering did not coincide with a pronounced maximum in pollinator-related insect activity. However, the quantitative patterns observed suggest that, in this context, T. cordata provides only modest support for pollinator guilds, and its role is better interpreted as one component of wider forest insect diversity rather than as a primary driver of pollination services. Full article

Vernonia amygdalina Delile (Asteraceae), commonly known as bitter leaf, is a tropical shrub that may potentially serve as a biopesticide against the Colorado potato beetle Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), a key pest of potatoes. The beetle’s behavioral response to the methanolic leaf extract of V. amygdalina was evaluated in this study. Using no-choice, dual-choice, and wind-tunnel assays under laboratory conditions, we evaluated responses of larvae and adults to potato leaf discs treated with V. amygdalina extract in a randomized complete block design, measuring feeding behavior, leaf damage levels, and remaining leaf area. The results showed that V. amygdalina had no biocidal effects against the beetle, as no mortality was incurred. However, dose-linked antifeedant effects were evident in both no-choice and dual-choice arenas. Vernonia amygdalina minimized leaf-area loss most effectively at the highest concentration, especially against the larvae. The extract showed no olfactory repellency but acted as an antifeedant, possibly through contact or taste (gustatory) receptors. The consistent behavioral avoidance at higher concentrations suggests that V. amygdalina acts as a form of deterrent against the Colorado potato beetle. Full article