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Sensory neuron membrane proteins (SNMPs) play critical roles in insect olfactory system. However, functional studies outside of Drosophila remain limited, especially in Coleoptera species. In our previous study, a SNMP1 (CbuqSNMP1b) was identified from Cyrtotrachelus buqueti (Coleoptera: Curculionidae), an insect pest that seriously influence the development of the bamboo industry. Here in a membrane protein yeast two-hybrid system, protein interactions between CbuqSNMP1b as a bait protein and a cDNA library of antenna of male C. buqueti adults as prey protein were assessed. Of 29 proteins identified as putative interactors, the Minus-C odorant-binding protein (CbuqOBP1) was selected for further analysis. The interaction between CbuqSNMP1b and CbuqOBP1 was further confirmed by both the in vivo yeast spotting analysis and the in vitro glutathione-S-transferase pull-down assay. Fluorescence binding assays indicated that the interaction between CbuqSNMP1b and CbuqOBP1 could enhance the binding abilities of CbuqOBP1 to four adult C. buqueti biologically active volatiles. The knockdown of CbuqSNMP1b + CbuqOBP1 expression by RNA interference significantly reduced the behavior responses of male adults to ethyl hexanoate and trans,trans-2,4-Nonadienal. These results increase our understanding of insect SNMP1 and will aid in exploring the underlying mechanisms of CbuqSNMP1b functions in the future., Competing Interests: Declaration of competing interest The authors declare that there are no conflicts of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Here, we describe patterns of reproduction and flight phenology of putative Phloeosinus punctatus in giant sequoia groves and compare morphology and genotypes of beetles from sympatric giant sequoia (Sequoiadendron giganteum) and California incense-cedar (Calocedrus decurrens). Surveys conducted in 2022 revealed that numerous branches fall from giant sequoia crowns (on average ~30 branches/tree), with 20%-50% of trees per site shedding branches, depositing breeding material for beetles on the forest floor that subsequently becomes colonized. When noninfested branches cut from mature giant sequoias were placed at the ground surface, they were colonized by P. punctatus and produced an average of 28 beetles/kg branch. Climbing and examination of sequoia crowns in 2023 showed that 75% of mature trees across 11 groves showed evidence of adult beetle entrance holes in their crowns. In 2021, tests with sticky traps showed that beetles alighted on fallen branches from 20th May to 20th August (peak landing: 2nd July); a logistic model developed from emergence data in 2021 and 2022 predicts the emergence of F1 offspring from branches between 10th July and 1st September (peak emergence: 8th August). Beetles emerging from giant sequoia preferred to settle on giant sequoia, did not reproduce in incense-cedar, and diverged morphologically from beetles emerging from incense-cedar. However, phylogenetic analysis of three genes (28S, CAD, and COI) revealed no clear pattern of sequence divergence, suggesting a single species (P. punctatus) that colonizes both hosts, though cryptic speciation may not be detectable with standard barcoding genes. Ecological and potential management implications are discussed., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America.)

Niphades castanea Chao (Coleoptera: Curculionidae), an important fruit insect pest of chestnuts (Castanea spp.), could cause chestnut involucre abscission ahead of time through larvae boring and feeding basal involucres, eventually causing huge economic losses. In this research, mitochondrial (COI and COII) and nuclear (ITS1) markers were used to investigate genetic variation among 15 different geographical populations of chestnut pest N castanea. The molecular diversity of N. castanea populations revealing three main phylogenetic clusters, with cluster I specifically distributed at high elevations in the western sampling points. Mitochondrial genes indicated population expansion events, and the ITS1 marker suggested a history of population expansion. Genetic diversity differentiation was significant among populations, indicating that geographical isolation impacts genetic differentiation among these places. AMOVA analyses confirmed substantial genetic differentiation between populations. Mantel correlogram analyses revealed a significant positive correlation between genetic differentiation and altitude/geographical distance at lower elevations and ranges, which reversed to a negative correlation at higher altitudes and ranges for all markers, indicating the role of altitude and geographical distance in shaping genetic diversity in N. castanea. This study contributes to a comprehensive understanding of the distribution, genetic diversity, and evolutionary history of N. castanea in the central of China, underscoring the impact of geographical factors on its genetic structure., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Mao et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

The rise of angiosperms to ecological dominance and the breakup of Gondwana during the Mesozoic marked major transitions in the evolutionary history of insect-plant interactions. To elucidate how contemporary trophic interactions were influenced by host plant shifts and palaeogeographical events, we integrated molecular data with information from the fossil record to construct a time tree for ancient phytophagous weevils of the beetle family Belidae. Our analyses indicate that crown-group Belidae originated approximately 138 Ma ago in Gondwana, associated with Pinopsida (conifer) host plants, with larvae likely developing in dead/decaying branches. Belids tracked their host plants as major plate movements occurred during Gondwana's breakup, surviving on distant, disjunct landmasses. Some belids shifted to Angiospermae and Cycadopsida when and where conifers declined, evolving new trophic interactions, including brood-pollination mutualisms with cycads and associations with achlorophyllous parasitic angiosperms. Extant radiations of belids in the genera Rhinotia (Australian region) and Proterhinus (Hawaiian Islands) have relatively recent origins., Competing Interests: XL, AM, RO, DC, BF, AS, MF, CO, SS, SS, WT, DM No competing interests declared, (© 2024, Li et al.)

Since the inception of the field of evolution, mimicry has yielded insights into foundational evolutionary processes, including adaptive peak shifts, speciation, and the emergence and maintenance of phenotypic polymorphisms. 1 , 2 , 3 In recent years, the coevolutionary processes generating mimicry have gained increasing attention from researchers. Despite significant advances in understanding Batesian and Müllerian mimicry in Lepidopteran systems, few other mimetic systems have received similar detailed research. Here, we present a Batesian mimicry complex involving flightless, armored Pachyrhynchus weevils and their winged Doliops longhorn beetle mimics and examine their coevolutionary patterns within the Philippine archipelagos. Pachyrhynchus weevils are primarily found in the Philippines, where distinct species radiations have occurred on different islands, each with unique color patterns serving as a warning to predators. This defensive trait and mimicry between unrelated species were first described by Wallace in 1889. Notably, the distantly related longhorn beetle Doliops, despite being soft-bodied and ostensibly palatable, mimics the heavily armored, flightless Pachyrhynchus. To address mimicry in this system, we reconstructed the phylogeny of Doliops using a probe set consisting of 38,000 ultraconserved elements. Our study examines the following questions central to understanding the Pachyrhynchus-Doliops mimicry system: (1) to what extent are coevolutionary interactions conserved (i.e., lineage-constrained) and (2) are the codiversification patterns primarily driven by biotic or abiotic factors? 4 , 5 , 6 To assess color mimicry and cospeciation, we examined the evolution of nanostructure-based warning colors and the effect of island biogeography on cospeciation. Our findings demonstrate the beetle's ability to repeatedly evolve multiple solutions to similar evolutionary challenges, evolving similar color patterns using different types of photonic crystals with varying degrees of order. We revealed that the observed pattern of cospeciation is driven mainly by abiotic factors from their biogeographic history. Unlike the patterns of coevolution seen between angiosperms and insect lineages, 7 most ecological interactions do not persist longer than a few million years, leading to patterns of modularity rather than ecological nestedness. 4 , 6 , 7 ., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Hylurgus ligniperda belongs to Hylurgus Latreille, Curculionidae, Coleoptera. It primarily damages the base and roots of the trunk of pine plants. Short-term treatment at 42 °C can damage Hylurgus ligniperda; therefore, temperature is a vital factor limiting its spread. Heat shock proteins (HSPs) can protect, remove, and repair proteins to help H. ligniperda withstand high temperatures. However, information on HSP genes in H. ligniperda remains limited. In the study, we considered H. ligniperda as the focus of research and identified 56 HligHSP genes at the genome-wide level. These genes were mapped to the cytoplasm or nucleus. An identical subfamily exhibited a closely similar distribution of conserved domains. Combined with the transcriptome data collected in previous studies, we screened six candidate genes, namely HligsHSP-3, HligsHSP-4, HligHSP60-16, HligHSP70-3, HligHSP70-4, and HligHSP90-1, which are specifically expressed during different high-temperature treatments. A quantitative polymerase chain reaction was performed to measure the expression of these six HligHSPs in seven temperature treatment conditions. These genes may be involved in the heat resistance mechanism in adults. Our findings provided a foundation for further studying the heat resistance mechanism in H. ligniperda., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Insects detect odours using odorant receptors (ORs) expressed in olfactory sensory neurons (OSNs) in the antennae. Ecologically important odours are often detected by selective and abundant OSNs; hence, ORs with high antennal expression. However, little is known about the function of highly expressed ORs in beetles, since few ORs have been functionally characterized. Here, we functionally characterized the most highly expressed OR (ItypOR36) in the bark beetle Ips typographus L. (Coleoptera, Curculionidae, Scolytinae), a major pest of spruce. We hypothesized that this OR would detect a compound important to beetle fitness, such as a pheromone component. We next investigated the antennal distribution of this OR using single sensillum recordings (SSR) and in situ hybridization, followed by field- and laboratory experiments to evaluate the behavioural effects of the discovered ligand., Results: We expressed ItypOR36 in HEK293 cells and challenged it with 64 ecologically relevant odours. The OR responded exclusively to the monoterpene-derived ketone lanierone with high sensitivity. Lanierone is used in chemical communication in North American Ips species, but it has never been shown to be produced by I. typographus, nor has it been studied in relation to this species' sensory physiology. Single sensillum recordings revealed a novel and abundant lanierone-responsive OSN class with the same specific response as ItypOR36. Strikingly, these OSNs were co-localized in sensilla together with seven different previously described OSN classes. Field experiments revealed that low release rates of lanierone inhibited beetle attraction to traps baited with aggregation pheromone, with strongest effects on males. Female beetles were attracted to lanierone in laboratory walking bioassays., Conclusions: Our study highlights the importance of the so-called 'reverse chemical ecology' approach to identify novel semiochemicals for ecologically important insect species. Our discovery of the co-localization pattern involving the lanierone OSN class suggests organizational differences in the peripheral olfactory sense between insect orders. Our behavioural experiments show that lanierone elicits different responses in the two sexes, which also depend on whether beetles are walking in the laboratory or flying in the field. Unravelling the source of lanierone in the natural environment of I. typographus is required to understand these context-dependent behaviours., Competing Interests: Declarations. Ethics approval and consent to participate: Not applicable. Consent for publication: Not applicable. Competing interests: The authors declare that they have no competing interests., (© 2024. The Author(s).)

The Hylurgini tribe (Coleoptera: Curculionidae: Scolytinae) comprises commercially significant bark beetles, including invasive species within the genera Dendroctonus and Hylurgus. These invasive species coexist with native Tomicus species of Hylurgini and cooperatively infest host trees in China. However, we lack sufficient mitochondrial genome data of Hylurgini to conduct phylogenetic studies, clarify the phylogenetic relationships of the above species, and improve the understanding of niche divergence and common hazards. Here, we sequenced and analyzed the mitochondrial genomes of seven Hylurgini species, including Dendroctonus valens, Hylurgus ligniperda, Hylurgus micklitzi, Tomicus piniperda, Tomicus brevipilosus, Tomicus minor and Tomicus yunnanensis. All sequenced mitochondrial genomes ranged from 15,339 bp to 17,545 bp in length, and their AT contents ranged from 73.24% to 78.81%. The structure of the seven mitochondrial genomes was consistent with that of ancestral insects. Based on 13 protein-coding genes from the reported mitochondrial genomes of 29 species of bark beetles, we constructed phylogenetic trees using maximum likelihood and Bayesian inference methods. The topology of the two phylogenetic trees was almost consistent. The findings elucidated the taxonomy classification of Hylurgini and the evolutionary connections of its sister taxa within the Scolytinae. This study offers insights for examining the evolutionary connections between invasive and native bark beetles, as well as the molecular identification and detection of newly invading species., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 An et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

The coffee berry borer (CBB) Hypothenemus hampei was first described in Africa in 1867 and has spread to all major coffee-producing regions worldwide, including Jamaica. Using long-read sequencing, we produced a new high-quality reference genome (172.7 Mb) for the Jamaican strain of the CBB, with 93% of the genome assembled into 14 scaffolds. Whole genome sequencing of pooled samples from different populations across Jamaica showed that the CBB harbors low levels of genetic diversity alongside an excess of low-frequency alleles, indicative of a recent genetic bottleneck. The analyses also showed a recent surge in the activity of transposable elements (TEs), particularly LINE/R1 and LTR/Gypsy elements, within CBB populations. Our findings offer first insights into the evolutionary genomics of CBB populations in Jamaica, highlighting the potential role of TEs in shaping the genome of this important pest species., Competing Interests: Conflict of Interest None declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of Society for Molecular Biology and Evolution.)

Bark and ambrosia beetles are among the most ecologically and economically damaging introduced plant pests worldwide. Life history traits including polyphagy, haplodiploidy, inbreeding polygyny, and symbiosis with fungi contribute to their dispersal and impact. Species vary in their interactions with host trees, with many attacking stressed or recently dead trees, such as the globally distributed Euwallacea similis (Ferrari). Other species, like the Polyphagous Shot Hole Borer Euwallacea fornicatus (Eichhoff), can attack over 680 host plants and is causing considerable economic damage in several countries. Despite their notoriety, publicly accessible genomic resources for Euwallacea Hopkins species are scarce, hampering our understanding of their invasive capabilities as well as modern control measures, surveillance, and management. Using a combination of long and short read sequencing platforms, we assembled and annotated high quality (BUSCO > 98% complete) pseudo-chromosome-level genomes for these species. Comparative macrosynteny analysis identified an increased number of pseudo-chromosome scaffolds in the haplodiploid inbreeding species of Euwallacea compared to diploid outbred species, due to fission events. This suggests that life history traits can impact chromosome structure. Further, the genome of E. fornicatus had a higher relative proportion of repetitive elements, up to 17% more, than E. similis. Metagenomic assembly pipelines identified microbiota associated with both species including Fusarium fungal symbionts and a novel Wolbachia strain. These novel genomes of haplodiploid inbreeding species will contribute to the understanding of how life history traits are related to their evolution and to the management of these invasive pests., (© The Author(s) 2024. Published by Oxford University Press on behalf of Society for Molecular Biology and Evolution.)

The red palm weevil, Rhynchophorus ferrugineus (Oliver, 1970) (Coleoptera: Dryophthoridae) is the most devastating insect-pest of palm trees worldwide. Synthetic insecticides are the most preferred tool for the management of RPW. Alternatively, RNA interference (RNAi) mediated silencing of crucial genes provides reasonable control of insect pests. Recently, we have targeted four important genes; ecdysone receptor (EcR), serine carboxypeptidase (SCP), actin and chitin-binding peritrophin (CBP) in the 3rd and 5th instar larvae RPW. The results from 20 days trial showed that the survival rate of 3rd instar larvae fed on SCP and actin dsRNAs exhibited the lowest survival (12-68%). While, in the 5th instar larvae, the lowest survival rate (24%) was recorded for SCP after 20 days of incubation. Similarly, the weight of the 3rd and 5th instar larvae treated with SCP and actin was significantly reduced to 2.30-2.36 g and 4.64-4.78 g after 6 days of dsRNA exposure. The larval duration was also decreased significantly in the larvae treated with all the dsRNA treatments. The qRT-PCR results confirmed a significant suppression of the targeted genes as 90-97% and 85-93% in the 3rd and 5th instar larvae, respectively. The results suggest that the SCP and the actin genes can be promising targets to mediate RNAi-based control of RPW., Competing Interests: The authors declare no conflict of interests., (Copyright: © 2024 Sattar et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Innate immunity, the body's initial defense against bacteria, fungi, and viruses, heavily depends on antimicrobial peptides (AMPs), which are small molecules produced by all living organisms. Insects, with their vast biodiversity, are one of the most abundant and innovative sources of AMPs. In this study, AMPs from the red palm weevil (RPW) Rhynchophorus ferrugineus (Coleoptera: Curculionidae), a known invasive pest of palm species, were examined. The AMPs were identified in the transcriptomes from different body parts of male and female adults, under different experimental conditions, including specimens collected from the field and those reared in the laboratory. The RPW transcriptomes were examined to predict antimicrobial activity, and all sequences putatively encoding AMPs were analyzed using several machine learning algorithms available in the CAMP R3 database. Additionally, anticancer, antiviral, and antifungal activity of the peptides were predicted using iACP, AVPpred, and Antifp server tools, respectively. Physicochemical parameters were assessed using the Antimicrobial Peptide Database Calculator and Predictor. From these analyses, 198 putatively active peptides were identified, which can be tested in future studies to validate the in silico predictions. Genome-wide analysis revealed that several AMPs have predominantly emerged through gene duplication. Noticeably, we detect a newly originated defensin allele from an ancestral defensin via the deletion of two amino acids following gene duplication in RPW, which may confer an enhanced resilience to microbial infection. Our study shed light on AMP gene families and shows that high duplication and deletion rates are essential to achieve a diversity of antimicrobial mechanisms; hence, we propose the RPW AMPs as a model for exploring gene duplication and functional variations against microbial infection.

Identifying dormancy traits is important for predicting insect population success, particularly in a changing climate that could disrupt evolved traits. The mountain pine beetle (Dendroctonus ponderosae Hopkins) is native to North America, is responsible for millions of acres of tree mortality, and is expanding northward in Canada. Research has identified thermal traits important to epidemic-phase ecology that vary among populations. Genomic research identified 3 mountain pine beetle haplogroups representing Pleistocene glacial refugia. Significant variation in generation timing aligning with the haplogroups has been observed. The adult stage was previously identified as the likely cause of differences among populations, although the mechanism(s) remain unclear. We tested for an adult summer diapause that varies among populations from 2 haplogroups, southern Colorado (CO) (central haplogroup) and southern Idaho (ID) (eastern haplogroup) using respirometry and reproduction experiments. Warm temperatures (25 °C) resulted in reduced respiration rates of central haplogroup mountain pine beetle compared to a cool temperature treatment (15 °C), whereas respiration of the eastern haplogroup did not differ between the treatments. Mated pairs of central haplogroup mountain pine beetle reared/held at 15 °C were more likely to be classified with a higher reproductive success rating compared to pairs reared/held at 25 °C. These results support a facultative summer adult diapause in southern CO central haplogroup mountain pine beetle. Manifestation of this diapause was low/absent among adults from the northerly ID location. This diapause likely serves to maintain univoltinism shown to be important for mountain pine beetle epidemic-phase ecology. The variation occurring among haplogroups highlights the long-term, evolved processes driving local adaptations in mountain pine beetle., (Published by Oxford University Press on behalf of Entomological Society of America 2024.)

Dendroctonus armandi (Tsai and Li) (Coleoptera: Curculionidae: Scolytinae) is regarded as the most destructive forest pest in the Qinling and Bashan Mountains of China. The sex determination of Dendroctonus armandi plays a significant role in the reproduction of its population. In recent years, the role of the fem-1 gene in sex determination in other insects has been reported. However, the function and expression of the fem-1 gene in Dendroctonus armandi remain uncertain. In this study, three fem-1 genes were cloned and characterized. These were named Dafem-1 A, Dafem-1 B, and Dafem-1 C, respectively. The expression levels of these three Dafem-1 genes vary at different stages of development and between the sexes. In response to different environmental treatments, including temperature, nutrients, terpenoids, and feeding duration, significant differences were observed between the three Dafem-1 genes at different developmental stages and between males and females. Furthermore, injection of double-stranded RNA (dsRNA) targeting the expressions of the Dafem-1 A, Dafem-1 B, and Dafem-1 C genes resulted in increased mortality, deformity, and decreased emergence rates, as well as an imbalance in the sex ratio. Following the interference with Dafem-1 A and Dafem-1 C, no notable difference was observed in the expression of the Dafem-1 B gene. Similarly, after the interference with the Dafem-1 B gene, no significant difference was evident in the expression levels of the Dafem-1 A and Dafem-1 C genes. However, the interference of either the Dafem-1 A or Dafem-1 C gene results in the downregulation of the other gene. The aforementioned results demonstrate that the Dafem-1 A, Dafem-1 B, and Dafem-1 C genes play a pivotal role in the regulation of life development and sex determination. Furthermore, it can be concluded that external factors such as temperature, nutrition, terpenoids, and feeding have a significant impact on the expression levels of the Dafem-1 A, Dafem-1 B, and Dafem-1 C genes. This provides a crucial theoretical foundation for further elucidating the sex determination mechanism of Dendroctonus armandi .

Background: Hylurgus ligniperda (Coleoptera: Curculionidae) is a worldwide forest quarantine pest. It is widely distributed, has many host tree species, and possesses strong adaptability. To explore its environmental adaptability and the related molecular mechanisms, we conducted chromosome-level genome sequencing and analyzed the transcriptome under different environmental factors, identifying key expressed genes., Results: We employed PacBio, Illumina, and Hi-C sequencing techniques to assemble a 520 Mb chromosomal-level genome of H. ligniperda, obtaining an N50 of 39.97 Mb across 138 scaffolds. A total of 10,765 protein-coding genes were annotated after repeat masking. Fourteen chromosomes were identified, among which Hyli14 was determined to be the sex chromosome. Survival statistics were tested over various growth periods under high temperature and low humidity conditions. The maximum survival period of adults reached 292 days at 25 °C, 65% relative humidity. In comparison, the maximum survival period was 14 days under 35 °C, 65% relative humidity, and 106 days under 25°C, 40% relative humidity. This indicated that environmental stress conditions significantly reduced adults' survival period. We further conducted transcriptome analysis to screen for potentially influential differentially expressed genes, such as CYP450 and Histone. Subsequently, we performed gene family analysis to gain insights into their functions and interactions, such as CYP450 and Histone. CYP450 genes affected the detoxification metabolism of enzymes in the Cytochrome P450 pathway to adapt to different environments. Histone genes are involved in insect hormone biosynthesis and longevity-regulating pathways in H. ligniperda to adapt to environmental stress., Conclusions: The genome at the chromosome level of H. ligniperda was assembled for the first time. The mortality of H. ligniperda increased significantly at 35 ℃, 65% RH, and 25 ℃, 40% RH. CYP450 and Histone genes played an important role in response to environmental stress. This genome offers a substantial genetic resource for investigating the molecular mechanisms behind beetle invasion and spread., (© 2024. The Author(s).)

Little resistance to the pea weevil insect pest ( Bruchus pisorum ) is available in pea ( Pisum sativum ) cultivars, highlighting the need to search for sources of resistance in Pisum germplasm and to decipher the genetic basis of resistance. To address this need, we screened the response to pea weevil in a Pisum germplasm collection (324 accession, previously genotyped) under field conditions over four environments. Significant variation for weevil seed infestation (SI) was identified, with resistance being frequent in P. fulvum , followed by P. sativum ssp. elatius , P. abyssinicum , and P. sativum ssp. humile . SI tended to be higher in accessions with lighter seed color. SI was also affected by environmental factors, being favored by high humidity during flowering and hampered by warm winter temperatures and high evapotranspiration during and after flowering. Merging the phenotypic and genotypic data allowed genome-wide association studies (GWAS) yielding 73 markers significantly associated with SI. Through the GWAS models, 23 candidate genes were found associated with weevil resistance, highlighting the interest of five genes located on chromosome 6. These included gene 127136761 encoding squalene epoxidase; gene 127091639 encoding a transcription factor MYB SRM1; gene 127097033 encoding a 60S ribosomal protein L14; gene 127092211, encoding a BolA-like family protein, which, interestingly, was located within QTL BpLD.I , earlier described as conferring resistance to weevil in pea; and gene 127096593 encoding a methyltransferase. These associated genes offer valuable potential for developing pea varieties resistant to Bruchus spp. and efficient utilization of genomic resources through marker-assisted selection (MAS).

The red palm weevil (RPW), Rhynchophorus ferrugineus (Olivier), also known as the Asian palm weevil, is an invasive pest that causes widespread damage to palm trees around the globe. As pheromone communication is crucial for their mass attack and survival on palm trees, the olfactory concept of pest control strategies has been widely explored recently. We aim to understand the molecular basis of olfaction in RPW by studying one of the key olfactory proteins in insect pheromone communication, sensory neuron membrane proteins (SNMPs). SNMPs belong to the CD36 (cluster of differentiation 36) family that perform two distinct olfactory roles in insects, either in pheromone (odorant) transfer to the odorant receptors (SNMP1) or in the pheromone clearing process (SNMP2). In this study, we performed antennal transcriptomic screening and identified six SNMPs, mapping them on the R. ferrugineus genome, and confirmed four distinct SNMPs. Both SNMP1 proteins in RPW, viz., RferSNMPu1 and RferSNMPu2, were mapped onto the same scaffold in different loci in the RPW genome. To further understand the function of these proteins, we first classified them using phylogenetic analysis and checked their tissue-specific expression patterns. Further, we measured the relative transcript abundance of SNMPs in laboratory-reared, field-collected adults and pheromone-exposure experiments, ultimately identifying RferSNMPu1 as a potential candidate for functional analysis. We mapped RferSNMPu1 expression in the antennae and found that expression patterns were similar in both sexes. We used RNAi-based gene silencing to knockdown RferSNMPu1 and tested the changes in the RPW responses to aggregation pheromone compounds, 4-methyl-5-nonanol (ferrugineol) and 4-methyl-5-nonanone (ferrugineone), and a kairomone, ethyl acetate using electroantennogram (EAG) recordings. We found a significant reduction in the EAG recordings in the RferSNMPu1 knockdown strain of adult RPWs, confirming its potential role in pheromone detection. The structural modelling revealed the key domains in the RferSNMPu1 structure, which could likely be involved in pheromone detection based on the identified ectodomain tunnels. Our studies on RferSNMPu1 with a putative role in pheromone detection provide valuable insight into understanding the olfaction in R. ferrugineus as well as in other Curculionids, as SNMPs are under-explored in terms of its functional role in insect olfaction. Most importantly, RferSNMPu1 can be used as a potential target for the olfactory communication disruption in the R. ferrugineus control strategies., (© 2024. The Author(s).)

Four Sueus Murayama, 1951 species occur in Southeast Asia and Oceania. They all likely have a female-biased haplodiploid inbreeding mating system and feed on symbiotic ambrosia fungi. These life history traits increase the potential of adventive events. Indeed, Sueus has been recently discovered on the Caribbean island of Martinique. Morphological variation has been observed among some populations of Sueus niisimai (Eggers, 1926), which questioned species boundaries. Given the beetle's potential economic importance, we provide a molecular phylogeny as a foundation for systematic study and review the status of the known species. We sequenced a total of 1117 nucleotides from mitochondrial COI and nuclear CAD genes for 25 specimens. Parsimony and Bayesian phylogenies were similar in topology and demonstrated the sister placement of S. granulatus (Eggers, 1936) to the other Sueus species, reciprocal monophyly of S. niisimai and S. pilosus (Eggers, 1936) status restored, the monophyly of S. obesus Browne, 1977 and elevated levels of nucleotide divergence (interspecific = 16-22%). Sueus chatterjeei Smith & Cognato sp. nov. (India) and Sueus insulanus Schiffer, Smith & Cognato sp. nov. (Papua New Guinea) are described. Hyorrhynchus granulatus Eggers, 1936 is removed from synonymy with Hyorrhynchus lewisi Blandford, 1894 and reinstated as a valid species, Sueus granulatus (Eggers, 1936) status restored, comb. nov. A key to the eight recognized species is given. In addition, the identity of the Martinique species is revised as S. pilosus. Geographic distribution of species and the potential existence of cryptic species are discussed.

The subfamily Molytinae (Coleoptera: Curculionidae), being the second largest group within the family Curculionidae, exhibits a diverse range of hosts and poses a serious threat to agricultural and forestry industries. We used 1,290 cytochrome c oxidase subunit I (COI) barcodes to assess the efficiency of COI barcodes in species differentiation and uncover cryptic species diversity within weevils of Molytinae. The average Kimura 2-parameter distances within species, genus, and subfamily were 2.90%, 11.0%, and 22.26%, respectively, indicating significant genetic differentiation at both levels. Moreover, there exists a considerable degree of overlap between intraspecific (0%-27.50%) and interspecific genetic distances (GDs; 0%-39.30%). The application of Automatic barcode gap discovery, Assemble Species by Automatic Partitioning, Barcode Index Number, Poisson Tree Processes (PTP), Bayesian Poisson Tree Processes (bPTP), and jMOTU resulted in the identification of 279, 275, 494, 322, 320, and 279 molecular operational taxonomic units, respectively. The integration of 6 methods successfully delimited species of Molytinae in 86.6% of all examined morphospecies, surpassing a threshold value of 3% GD (73.0%). A total of 28 morphospecies exhibiting significant intraspecific divergences were assigned to multiple MOTUs, respectively, suggesting the presence of cryptic diversity or population divergence. The identification of cryptic species within certain morphological species in this study necessitates further investigation through comprehensive taxonomic practices in the future., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America.)

The cotton boll weevil (CBW, Anthonomus grandis) stands as one of the most significant threats to cotton crops (Gossypium hirsutum). Despite substantial efforts, the development of a commercially viable transgenic cotton event for effective open-field control of CBW has remained elusive. This study describes a detailed characterization of the insecticidal toxins Cry23Aa and Cry37Aa against CBW. Our findings reveal that CBW larvae fed on artificial diets supplemented exclusively with Cry23Aa decreased larval survival by roughly by 69%, while supplementation with Cry37Aa alone displayed no statistical difference compared to the control. However, the combined provision of both toxins in the artificial diet led to mortality rates approaching 100% among CBW larvae (LC 50 equal to 0.26 PPM). Additionally, we engineered transgenic cotton plants by introducing cry23Aa and cry37Aa genes under control of the flower bud-specific pGhFS4 and pGhFS1 promoters, respectively. Seven transgenic cotton events expressing high levels of Cry23Aa and Cry37Aa toxins in flower buds were selected for greenhouse bioassays, and the mortality rate of CBW larvae feeding on their T 0 and T 1 generations ranged from 75% to 100%. Our in silico analyses unveiled that Cry23Aa displays all the hallmark characteristics of β-pore-forming toxins (β-PFTs) that bind to sugar moieties in glycoproteins. Intriguingly, we also discovered a distinctive zinc-binding site within Cry23Aa, which appears to be involved in protein-protein interactions. Finally, we discuss the major structural features of Cry23Aa that likely play a role in the toxin's mechanism of action. In view of the low LC 50 for CBW larvae and the significant accumulation of these toxins in the flower buds of both T 0 and T 1 plants, we anticipate that through successive generations of these transgenic lines, cotton plants engineered to overexpress cry23Aa and cry37Aa hold promise for effectively managing CBW infestations in cotton crops., Competing Interests: Declaration of Competing Interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The Asian palm weevil, Rhynchophorus ferrugineus, is a tremendously important agricultural pest primarily adapted to palm trees and causes severe destruction, threatening sustainable palm cultivation worldwide. The host plant selection of this weevil is mainly attributed to the functional specialization of odorant receptors (ORs) that detect palm-derived volatiles. Yet, ligands are known for only two ORs of R. ferrugineus, and we still lack information on the mechanisms of palm tree detection. This study identified a highly expressed antennal R. ferrugineus OR, RferOR2, thanks to newly generated transcriptomic data. The phylogenetic analysis revealed that RferOR2 belongs to the major coleopteran OR group 2A and is closely related to a sister clade containing an R. ferrugineus OR (RferOR41) tuned to the non-host plant volatile and antagonist, α-pinene. Functional characterization of RferOR2 via heterologous expression in Drosophila olfactory neurons revealed that this receptor is tuned to several ecologically relevant palm-emitted odors, most notably ethyl and methyl ester compounds, but not to any of the pheromone compounds tested, including the R. ferrugineus aggregation pheromone. We did not evidence any differential expression of RferOR2 in the antennae of both sexes, suggesting males and females detect these compounds equally. Next, we used the newly identified RferOR2 ligands to demonstrate that including synthetic palm ester volatiles as single compounds and in combinations in pheromone-based mass trapping has a synergistic attractiveness effect to R. ferrugineus aggregation pheromone, resulting in significantly increased weevil catches. Our study identified a key OR from a palm weevil species tuned to several ecologically relevant palm volatiles and represents a significant step forward in understanding the chemosensory mechanisms of host detection in palm weevils. Our study also defines RferOR2 as an essential model for exploring the molecular basis of host detection in other palm weevil species. Finally, our work showed that insect OR deorphanization could aid in identifying novel behaviorally active volatiles that can interfere with weevil host-searching behavior in sustainable pest management applications., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Interactions between animals and microbes are ubiquitous in nature and strongly impact animal physiology. These interactions are shaped by the host immune system, which responds to infections and contributes to tailor the associations with beneficial microorganisms. In many insects, beneficial symbiotic associations not only include gut commensals, but also intracellular bacteria, or endosymbionts. Endosymbionts are housed within specialized host cells, the bacteriocytes, and are transmitted vertically across host generations. Host-endosymbiont co-evolution shapes the endosymbiont genome and host immune system, which not only fights against microbial intruders, but also ensures the preservation of endosymbionts and the control of their load and location. The cereal weevil Sitophilus spp. is a remarkable model in which to study the evolutionary adaptation of the immune system to endosymbiosis owing to its binary association with a unique, relatively recently acquired nutritional endosymbiont, Sodalis pierantonius . This Gram-negative bacterium has not experienced the genome size shrinkage observed in long-term endosymbioses and has retained immunogenicity. We focus here on the sixteen antimicrobial peptides (AMPs) identified in the Sitophilus oryzae genome and their expression patterns in different tissues, along host development or upon immune challenges, to address their potential functions in the defensive response and endosymbiosis homeostasis along the insect life cycle. This article is part of the theme issue 'Sculpting the microbiome: how host factors determine and respond to microbial colonization'.

Background: The Argentine stem weevil (ASW, Listronotus bonariensis) is a significant pasture pest in Aotearoa New Zealand, primarily controlled by the parasitoid biocontrol agent Microctonus hyperodae. Despite providing effective control of ASW soon after release, M. hyperodae parasitism rates have since declined significantly, with ASW hypothesised to have evolved resistance to its biocontrol agent. While the parasitism arsenal of M. hyperodae has previously been investigated, revealing many venom components and an exogenous novel DNA virus Microctonus hyperodae filamentous virus (MhFV), the effects of said arsenal on gene expression in ASW during parasitism have not been examined. In this study, we performed a multi-species transcriptomic analysis to investigate the biology of ASW parasitism by M. hyperodae, as well as the decline in efficacy of this biocontrol system., Results: The transcriptomic response of ASW to parasitism by M. hyperodae involves modulation of the weevil's innate immune system, flight muscle components, and lipid and glucose metabolism. The multispecies approach also revealed continued expression of venom components in parasitised ASW, as well as the transmission of MhFV to weevils during parasitism and some interrupted parasitism attempts. Transcriptomics did not detect a clear indication of parasitoid avoidance or other mechanisms to explain biocontrol decline., Conclusions: This study has expanded our understanding of interactions between M. hyperodae and ASW in a biocontrol system of critical importance to Aotearoa-New Zealand's agricultural economy. Transmission of MhFV to ASW during successful and interrupted parasitism attempts may link to a premature mortality phenomenon in ASW, hypothesised to be a result of a toxin-antitoxin system. Further research into MhFV and its potential role in ASW premature mortality is required to explore whether manipulation of this viral infection has the potential to increase biocontrol efficacy in future., (© 2024. The Author(s).)

Three tree-killing bark beetles belonging to the genus Tomicus, Tomicus yunnanensis, Tomicus brevipilosus and Tomicus minor (Coleoptera; Curculionidae, Scolytinae), are serious wood-borers with larvae feeding on the phloem tissues of Pinus yunnanensis. The three Tomicus beetles, in some cases, coexist in a same habitat, providing a best system for exploring the conservation and divergence of reproductive genes. Here, we applied comparative transcriptomics and molecular biology approaches to characterize reproductive-related genes in three sympatric Tomicus species. Illumina sequencing of female and male reproductive systems and residual bodies generated a large number of clean reads, representing 185,920,232 sequences in T. yunnanensis, 169,153,404 in T. brevipilosus and 178,493,176 in T. minor that were assembled into 32,802, 56,912 and 33,670 unigenes, respectively. The majority of the genes had detectable expression in reproductive tissues (FPKM >1), particularly those genes in T. brevipilosus accounting for 76.61 % of the total genes. From the transcriptomes, totally 838 genes encoding 463 detoxification enzymes, 339 chemosensory membrane proteins and 36 ionotropic glutamate receptors (iGluRs) were identified, including 622 reproductive tissue-expressed genes. Of these, members of carboxylesterases (COEs), ionotropic receptors (IRs), sensory neuron membrane proteins (SNMPs) and iGluRs were highly conserved in gene numbers and sequence identities across three Tomicus species. Further, expression profiling analyses revealed a number of genes expressed in reproductive tissues and the diverse expression characteristics in these beetles. The results provide evidence for the conservation and differences of reproductive genes among three sympatric closely related beetles, helping understand their different reproductive strategies and the maximization of the reproductive success., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

The red palm weevil (RPW), Rhynchophorus ferrugineus (Curculionidae: Coleoptera) is a highly destructive global pest of coconut trees, with a preference for laying its eggs on new leaves. Females can identify where to lay eggs by using their sense of smell to detect specific odorants found in new leaves. In this study, we focused on the two odorants commonly found in new leaves by GC-MS: trans, trans-2,4-nonadienal and trans-2-nonenal. Our behavioral assays demonstrated a significant attraction of females to both of these odorants, with their electrophysiological responses being dose-dependent. Furthermore, we examined the expression patterns induced by these odorants in eleven RferOBP genes. Among them, RferOBP3 and RferOBP1768 exhibited the most significant and simultaneous upregulation. To further understand the role of these two genes, we conducted experiments with females injected with OBP-dsRNA. This resulted in a significant decrease in the expression of RferOBP3 and RferOBP1768, as well as impaired the perception of the two odorants. A fluorescence competitive binding assay also showed that both RferOBPs strongly bound to the odorants. Additionally, sequence analysis revealed that these two RferOBPs belong to the Minus-C family and possess four conserved cysteines. Molecular docking simulations showed strong interactions between these two RferOBPs and the odorant molecules. Overall, our findings highlight the crucial role of RferOBP3 and RferOBP1768 in the olfactory perception of the key odorants in coconut palm new leaves. This knowledge significantly improves our understanding of how RPW females locate sites for oviposition and lays the foundation for future research on the development of environmentally friendly pest attractants., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Chaojun Lv reports financial support was provided by Hainan Province Natural Science Foundation. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Chemoreception through odorant receptors (ORs), ionotropic receptors (IRs) and gustatory receptors (GRs) represents the functions of key proteins in the chemical ecology of insects. Recent studies have identified chemoreceptors in coleopterans, facilitating the evolutionary analysis of not only ORs but also IRs and GRs. Thus, Cerambycidae, Tenebrionidae and Curculionidae have received increased attention. However, knowledge of the chemoreceptors from Scarabaeidae is still limited, particularly for those that are sympatric. Considering the roles of chemoreceptors, this analysis could shed light on evolutionary processes in the context of sympatry. Therefore, the aim of this study was to identify and compare the repertoires of ORs, GRs and IRs between two sympatric scarab beetles, Hylamorpha elegans and Brachysternus prasinus. Here, construction of the antennal transcriptomes of both scarab beetle species and analyses of their phylogeny, molecular evolution and relative expression were performed. Thus, 119 new candidate chemoreceptors were identified for the first time, including 17 transcripts for B. prasinus (1 GR, 3 IRs and 13 ORs) and 102 for H. elegans (22 GRs, 14 IRs and 66 ORs). Orthologs between the two scarab beetle species were found, revealing specific expansions as well as absence in some clades. Purifying selection appears to have occurred on H. elegans and B. prasinus ORs. Further efforts will be focused on target identification to characterize kairomone and/or pheromone receptors., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

The Diaprepes root weevil (DRW), Diaprepes abbreviatus, is a broadly polyphagous invasive pest of agriculture in the southern United States and the Caribbean. Its genome was sequenced, assembled, and annotated to study genomic correlates of specialized plant-feeding and invasiveness and to facilitate the development of new methods for DRW control. The 1.69 Gb D. abbreviatus genome assembly was distributed across 653 contigs, with an N50 of 7.8 Mb and the largest contig of 62 Mb. Most of the genome was comprised of repetitive sequences, with 66.17% in transposable elements, 5.75% in macrosatellites, and 2.06% in microsatellites. Most expected orthologous genes were present and fully assembled, with 99.5% of BUSCO genes present and 1.5% duplicated. One hundred and nine contigs (27.19 Mb) were identified as putative fragments of the X and Y sex chromosomes, and homology assessment with other beetle X chromosomes indicated a possible sex chromosome turnover event. Genome annotation identified 18,412 genes, including 43 putative horizontally transferred (HT) loci. Notably, 258 genes were identified from gene families known to encode plant cell wall degrading enzymes and invertases, including carbohydrate esterases, polysaccharide lyases, and glycoside hydrolases (GH). GH genes were unusually numerous, with 239 putative genes representing 19 GH families. Interestingly, several other beetle species with large numbers of GH genes are (like D. abbreviatus) successful invasive pests of agriculture or forestry., (© The Author(s) 2023. Published by Oxford University Press on behalf of The American Genetic Association. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The red palm weevil (RPW) is a highly destructive pest that mainly affects palms, particularly date palms (Phoenix dactylifera), in the Arabian Gulf region. In this study, we present a near-chromosomal-level genome assembly of the RPW using a combination of PacBio HiFi and Dovetail Omini-C reads. The final genome assembly is around 779 Mb in size, with an N50 of ~43 Mb, consistent with our previous flow cytometry estimates. The completeness of the genome was confirmed through BUSCO analysis, which indicates the presence of 99.5% of BUSCO single copy orthologous genes. The genome annotation identified a total of 29,666 protein-coding, 1,091 tRNA and 543 rRNA genes. Overall, the proposed genome assembly is significantly superior to existing assemblies in terms of contiguity, integrity, and genome completeness., (© 2024. The Author(s).)

Bacillus thuringiensis is a Gram-positive bacterium known for its insecticidal proteins effective against various insect pests. However, limited strains and proteins target coleopteran pests like Anthonomous grandis Boheman, causing substantial economic losses in the cotton industry. This study focuses on characterizing a Bacillus sp. strain, isolated from Oncativo (Argentina), which exhibits ovoid to amorphous parasporal crystals and was designated Bt_UNVM-84. Its genome encodes genes for the production of two pairs of binary Vpb1/Vpa2 proteins and three Cry-like proteins showing similarity with different Cry8 proteins. Interestingly, this gene content was found to be conserved in a previously characterized Argentine isolate of B. thuringiensis designated INTA Fr7-4. SDS-PAGE analysis revealed a major band of 130 kDa that is proteolytically processed to an approximately 66-kDa protein fragment by trypsin. Bioassays performed with spore-crystal mixtures demonstrated an interesting insecticidal activity against the cotton boll weevil A. grandis neonate larvae, resulting in 91% mortality. Strain Bt_UNVM-84 is, therefore, an interesting candidate for the efficient biological control of this species, causing significant economic losses in the cotton industry in the Americas.

Cotton crop yields are largely affected by infestations of Anthonomus grandis, which is its main pest. Although Bacillus thuringiensis (Bt) derived proteins can limit insect pest infestations, the diverse use of control methods becomes a viable alternative in order to prolong the use of technology in the field. One of the alternative methods to Bt technology has been the utilization of certain Pseudomonas species highly efficient in controlling coleopteran insects have been used to produce highly toxic insecticidal proteins. This study aimed to evaluate the toxicity of IPD072Aa and PIP-47Aa proteins, isolated from Pseudomonas spp., in interaction with Cry1Ia10, Cry3Aa, and Cry8B proteins isolated from B. thuringiensis, to control A. grandis in cotton crops. The genes IPD072Aa and PIP-47Aa were synthesized and cloned into a pET-SUMO expression vector. Moreover, Cry1Ia10, Cry3Aa, and Cry8B proteins were obtained by inducing recombinant E. coli clones, which were previously acquired by our research group from the Laboratory of Bacteria Genetics and Applied Biotechnology (LGBBA). These proteins were visualized in SDS-PAGE, quantified, and incorporated into an artificial diet to estimate their lethal concentrations (LC) through individual or combined bioassays. The results of individual toxicity revealed that IPD072Aa, PIP-47Aa, Cry1Ia10, Cry3Aa, and Cry8B were efficient in controlling A. grandis, with the latter being the most toxic. Regarding interaction assays, a high synergistic interaction was observed between Cry1Ia10 and Cry3Aa. All interactions involving Cry3Aa and PIP-47Aa, when combined with other proteins, showed a clear synergistic effect. Our findings highlighted that the tested proteins in combination, for the most part, increase toxicity against A. grandis neonate larvae, suggesting possible constructions for pyramiding cotton plants to the manage and the control boll weevils., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Barbosa Rodrigues et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Pheromone-binding proteins (PBPs) play important roles in binding and transporting sex pheromones. However, the PBP genes identified in coleopteran insects and their information sensing mechanism are largely unknown. Cyrtotrachelus buqueti (Coleoptera: Curculionidae) is a major insect pest of bamboo plantations. In this study, a novel PBP gene, CbuqPBP2 , from C. buqueti was functionally characterized. CbuqPBP2 was more abundantly expressed in the antennae of both sexes than other body parts, and its expression level was significantly male-biased. Fluorescence competitive binding assays showed that CbuqPBP2 exhibited the strongest binding affinity to dibutyl phthalate ( K i = 6.32 μM), followed by styrene ( K i = 11.37 μM), among twelve C. buqueti volatiles. CbuqPBP2, on the other hand, showed high binding affinity to linalool ( K i = 10.55), the main volatile of host plant Neosinocalamus affinis . Furthermore, molecular docking also demonstrated the strong binding ability of CbuqPBP2 to dibutyl phthalate, styrene, and linalool, with binding energy values of -5.7, -6.6, and -6.0 kcal/mol, respectively, and hydrophobic interactions were the prevailing forces. The knockdown of CbuqPBP2 expression via RNA interference significantly reduced the electroantennography (EAG) responses of male adults to dibutyl phthalate and styrene. In conclusion, these results will be conducive to understanding the olfactory mechanisms of C. buqueti and promoting the development of novel strategies for controlling this insect pest.

A new species of bark beetle, Dryocoetiops krivetsae Kerchev, Mandelshtam, Bykov et Ilinsky, sp. n., from the southern part of Primorsky Krai (Russian Far East), is described. This is the northernmost discovery of the Oriental genus Dryocoetiops Schedl, 1957, and the first record of the genus in the Russian fauna. Phylogenetic analysis of nuclear and mitochondrial genes i) confirms an independent lineage of Dryocoetiops krivetsae and ii) indicates numerous conflicts of genera relationships in the tribe Dryocoetini.

The rice weevil, Sitophilus oryzae (Linnaeus, Coleoptera: Curculionidae), is a serious cosmopolitan pest that affects grain in storage and has developed high levels of resistance toward phosphine. In this study, RNA-seq data was used to study the phosphine resistance mechanisms in S. oryzae. Resistant and susceptible populations of S. oryzae were identified based on phosphine bioassays conducted in 32 populations collected across Tamil Nadu, India. Differential expression of mitochondrial (COX1, COX2, COX3, ND2, ND3, ATP6, and ATP8) and detoxification genes (Cyps, Gsts, and Cbe) were observed in the resistant and susceptible populations of S. oryzae. The previously characterized phosphine resistant gene, dld (dihydrolipoamide dehydrogenase) linked to the rph2 locus, was found to be up-regulated in resistant S. oryzae population (ISO-TNAU-RT) treated with phosphine. Also, the genes involved in Tricarboxylic acid (TCA) cycle were significantly down-regulated. In addition, a significant up-regulation in the expression of the antioxidant enzymes superoxide dismutase (2.5×) and catalase (2.1×) in ISO-TNAU-RT populations was recorded. Furthermore, a distinct amino acid substitution, Lysine > Glutamic acid (K141E) was identified in resistant phenotypes. In silico docking studies of both resistant and susceptible DLD protein with phosphine molecule revealed that the amino acid residues involved in the interaction were different. This suggested that the amino acid substitution might lead to structural modifications which reduces the affinity of the target (phosphine). This study provides insight on the various genes, pathways, and functional mechanisms having a significant role in phosphine resistance in S. oryzae., (© The Author(s) 2023. Published by Oxford University Press on behalf of Entomological Society of America.)

Weevils are an unusually species-rich group of phytophagous insects for which there is increasing evidence of frequent involvement in brood-site pollination. This study examines phylogenetic patterns in the emergence of brood-site pollination mutualism among one of the most speciose beetle groups, the flower weevils (subfamily Curculioninae). We analysed a novel phylogenomic dataset consisting of 214 nuclear loci for 202 weevil species, with a sampling that mainly includes flower weevils as well as representatives of all major lineages of true weevils (Curculionidae). Our phylogenomic analyses establish a uniquely comprehensive phylogenetic framework for Curculioninae and provide new insights into the relationships among lineages of true weevils. Based on this phylogeny, statistical reconstruction of ancestral character states revealed at least 10 independent origins of brood-site pollination in higher weevils through transitions from ancestral associations with reproductive structures in the larval stage. Broadly, our results illuminate the unexpected frequency with which true weevils-typically specialized phytophages and hence antagonists of plants-have evolved mutualistic interactions of ecological significance that are key to both weevil and plant evolutionary fitness and thus a component of their deeply intertwined macroevolutionary success.

Weevils have been shown to play significant roles in the obligate pollination of Australian cycads. In this study, we apply museomics to produce a first molecular phylogeny estimate of the Australian cycad weevils, allowing an assessment of their monophyly, placement and relationships. Divergence dating suggests that the Australian cycad weevils originated from the Late Oligocene to the Middle Miocene and that the main radiation of the cycad-pollinating groups occurred from the Middle to the Late Miocene, which is congruent with the diversification of the Australian cycads, thus refuting any notion of an ancient ciophilous system in Australia. Taxonomic studies reveal the existence of 19 Australian cycad weevil species and that their associations with their hosts are mostly non-species-specific. Co-speciation analysis shows no extensive co-speciation events having occurred in the ciophilous system of Australian cycads. The distribution pattern suggests that geographical factors, rather than diversifying coevolution, constitute the overriding process shaping the Australian cycad weevil diversity. The synchronous radiation of cycads and weevil pollinators is suggested to be a result of the post-Oligocene diversification common in Australian organisms.

The white potato worm Premnotrypes vorax (Hustache) (Coleoptera: Curculionidae) is one of the most destructive insect pests of potato crops in South America. Like many coleopteran insects, P. vorax shows low susceptibility to Cry insecticidal proteins produced by the bacterium Bacillus thuringiensis (Bt). However, the presence of Cry toxin receptors in the midgut of this this insect has never been studied. The main Cry-binding proteins described in other insect species are cadherin (CAD), aminopeptidase N (APN), alkaline phosphatase (ALP) and ATP-binding cassette (ABC) transporters. In this study, we analyzed and validated a de novo assembled transcriptome of Illumina sequencing data to identify and to characterize homologs of Cry toxin receptors. We identified the protein sequences in P. vorax that show high identity with their orthologous sequences of the Cry toxin binding proteins in other coleopteran larvae such as APN, ALP, CAD and ABC transporter. This study provides preliminary identification of putative receptor genes of Cry proteins that would be useful for future studies involving biocontrol of this important potato crop pest., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Velásquez C. et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Weevils represent one of the most prolific radiations of beetles and the most diverse group of herbivores on land. The phylogeny of weevils (Curculionoidea) has received extensive attention, and a largely satisfactory framework for their interfamilial relationships has been established. However, a recent phylogenomic study of Curculionoidea based on anchored hybrid enrichment (AHE) data yielded an abnormal placement for the family Belidae (strongly supported as sister to Nemonychidae + Anthribidae). Here we reanalyse the genome-scale AHE data for Curculionoidea using various models of molecular evolution and data filtering methods to mitigate anticipated systematic errors and reduce compositional heterogeneity. When analysed with the infinite mixture model CAT-GTR or using appropriately filtered datasets, Belidae are always recovered as sister to the clade (Attelabidae, (Caridae, (Brentidae, Curculionidae))), which is congruent with studies based on morphology and other sources of molecular data. Although the relationships of the 'higher Curculionidae' remain challenging to resolve, we provide a consistent and robust backbone phylogeny of weevils. Our extensive analyses emphasize the significance of data curation and modelling across-site compositional heterogeneity in phylogenomic studies.

Euwallacea interjectus (Curculionidae: Scolytinae) is an ambrosia beetle species in its early stages of research. Therefore, studying the related molecular mechanism associated with the development and egg laid is essential. Transcriptome sequencing was used in this study to compare the gene expression of the beetles at different developmental stages and female adults before and after oviposition. A total of 40,047 annotated unigenes were obtained. There were 4225 differentially expressed unigenes (DEUs) from larva to prepupa stage, 3651 DEUs between prepupa and pupa, 1675 DEUs generated from pupa to adult, and 4762 DEUs between females before and after oviposition. The most significant pathway differences between different development stages and before and after oviposition were selected through functional annotation of DEUs between different stages. Among them, there were many pathways related to protein metabolism including: neuroactive ligand-receptor interaction, endoplasmic reticulum and RNA transport. This study provides valuable information on the molecular regulation mechanism of development and the egg laid of E. interjectus., Competing Interests: Declaration of competing interest The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results., (Copyright © 2023 Elsevier Inc. All rights reserved.)

The granary weevil (Sitophilus granarius L.) is a major primary pest of stored cereals throughout the world. Among the major classes of plant secondary metabolites, flavonoids can affect insect feeding behaviour and their growth rate. In this study, the susceptibility of an anthocyanin-rich purple durum wheat genotype (T1303) to the granary weevil was evaluated in comparison with two yellow durum (Ofanto) and bread (Mec) wheat varieties. The feeding response and food utilisation efficiency by adult insects was also investigated by calculating nutritional indices in whole flour disk bioassays. Different levels of susceptibility to granary weevil emerged among genotypes tested. The mean food consumption by an insect, F1 progeny, and female parental offspring calculated for the T1303 genotype were significantly lower than those of yellow kernel wheat varieties. Moreover, T1303 genotype induced deterrence in the adult insects as demonstrated by the positive values of the food deterrence index. Besides, relative grow rate and efficiency conversion of ingested food indices were negative for T1303 and positive for both yellow wheat varieties indicating respectively a decrease and an increase of insect body weight during the bioassays. Finally, a higher mortality rate was recorded for insects fed on T1303 flour disks compared to disks obtained from yellow wheat varieties. These results provide evidence for the antifeedant and toxic effects of anthocyanins present in the T1303 pericarp against the granary weevil. Overall, this study contributes new insights into the mechanisms of host acceptance and food utilization by S. granarius and would be useful to identify antifeedant flavonoids as well as to develop varietal resistance-based strategies against this pest., (© 2023. Springer Nature Limited.)

A new species of the braconine genus Bracon (subgenus Bracon), B. hidalguensis sp. nov., is described from the locality of Tasquillo in the state of Hidalgo, central Mexico. The new species was reared from roots of Argemone ochroleuca Sweet (Papaveraceae), where specimens of the weevil species Conotrachelus leucophaeus (Champion) (Curculionidae) were also obtained and thus probably it represents its host. The new Bracon species was characterised molecularly with DNA barcoding (COI) and a fragment of the variable D23 region of the nuclear ribosomal 28S gene.

Xylosandrus compactus (Eichhoff) (Coleoptera: Curculionidae, Scolytinae) is a worldwide invasive species that causes huge economic loss and environmental damage in many countries. Traditional morphological characteristics make it hard to identify scolytines due to their tiny size. Besides, the intercepted insect samples are incomplete, and the limitation of insect (larvae and pupae) morphology makes morphological identification more difficult. The majority of the damage is caused by adults and fungi that serve as nutrition for their larvae. They destroy plant trunks, branches, and twigs, affecting plant transport tissues in both weak and healthy plants. An accurate, efficient, and economical molecular identification technique for X. compactus not restricted by professional taxonomic knowledge is necessary. In the present study, a molecular identification tool based on the mitochondrial DNA gene, cytochrome C oxidase subunit I (COI) was developed. A species-specific COI (SS-COI) PCR assay was designed to identify X. compactus regardless of the developmental stage. Twelve scolytines commonly found in eastern China, namely Xylosandrus compactus, X. crassiusculus, X. discolor, X. germanus, X. borealis, X. amputates, X. eupatorii, X. mancus, Xyleborinus saxesenii, Euwallacea interjectus, E. fornicatus, and Acanthotomicus suncei, were included in the study. Additionally, specimens of X. compactus from 17 different areas in China, as well as a specimen collected from the United Stated, were also analyzed. Results demonstrated the accuracy and high efficiency of the assay, regardless of the developmental stage or the type of specimen. These features provide a good application prospect for fundamental departments and can be used to prevent the harmful consequences of the spread of X. compactus., (© The Author(s) 2023. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Biocontrol is a key technology for the control of pest species. Microctonus parasitoid wasps (Hymenoptera: Braconidae) have been released in Aotearoa New Zealand as biocontrol agents, targeting three different pest weevil species. Despite their value as biocontrol agents, no genome assemblies are currently available for these Microctonus wasps, limiting investigations into key biological differences between the different species and strains., Methods and Findings: Here we present high-quality genomes for Microctonus hyperodae and Microctonus aethiopoides, assembled with short read sequencing and Hi-C scaffolding. These assemblies have total lengths of 106.7 Mb for M. hyperodae and 129.2 Mb for M. aethiopoides, with scaffold N50 values of 9 Mb and 23 Mb respectively. With these assemblies we investigated differences in reproductive mechanisms, and association with viruses between Microctonus wasps. Meiosis-specific genes are conserved in asexual Microctonus, with in-situ hybridisation validating expression of one of these genes in the ovaries of asexual Microctonus aethiopoides. This implies asexual reproduction in these Microctonus wasps involves meiosis, with the potential for sexual reproduction maintained. Investigation of viral gene content revealed candidate genes that may be involved in virus-like particle production in M. aethiopoides, as well as a novel virus infecting M. hyperodae, for which a complete genome was assembled., Conclusion and Significance: These are the first published genomes for Microctonus wasps which have been deployed as biocontrol agents, in Aotearoa New Zealand. These assemblies will be valuable resources for continued investigation and monitoring of these biocontrol systems. Understanding the biology underpinning Microctonus biocontrol is crucial if we are to maintain its efficacy, or in the case of M. hyperodae to understand what may have influenced the significant decline of biocontrol efficacy. The potential for sexual reproduction in asexual Microctonus is significant given that empirical modelling suggests this asexual reproduction is likely to have contributed to biocontrol decline. Furthermore the identification of a novel virus in M. hyperodae highlights a previously unknown aspect of this biocontrol system, which may contribute to premature mortality of the host pest. These findings have potential to be exploited in future in attempt to increase the effectiveness of M. hyperodae biocontrol., (© 2023. BioMed Central Ltd., part of Springer Nature.)

The evolutionary origins of mimicry in the Easter egg weevil, Pachyrhynchus, have fascinated researchers since first noted more than a century ago by Alfred Russel Wallace. Müllerian mimicry, or mimicry in which 2 or more distasteful species look similar, is widespread throughout the animal kingdom. Given the varied but discrete color patterns in Pachyrhynchus, this genus presents one of the best opportunities to study the evolution of both perfect and imperfect mimicry. We analyzed more than 10,000 UCE loci using a novel partitioning strategy to resolve the relationships of closely related species in the genus. Our results indicate that many of the mimetic color patterns observed in sympatric species are due to convergent evolution. We suggest that this convergence is driven by positive frequency-dependent selection. [Biogeography, discrete traits, frequency-dependent selection, mimicry, partitioning, Philippines, polymorphic, UCE.]., (© The Author(s) 2022. Published by Oxford University Press, on behalf of the Society of Systematic Biologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

The maize weevil, Sitophilus zeamais , is a worldwide pest that disproportionately affects subsistence farmers in developing countries. Damage from this pest threatens food security in these communities as widely available and effective control methods are lacking. With advances over the last decade in the development of genetic pest management techniques, addressing pest issues at the ecosystem level as opposed to the farm level may be a possibility. However, pest species selected for genetic management techniques require a well-characterized genome and few genomic tools have been developed for S. zeamais . Here, we have measured the genome size and developed the first genetic linkage map for this species. The genome size was determined using flow cytometry as 682 Mb and 674 Mb for females and males, respectively. The linkage map contains 11 linkage groups, which correspond to the 10 autosomes and 1 X-chromosome found in the species and it contains 1,121 SNPs. This linkage map will be useful for assembling a complete genome for S. zeamais ., Competing Interests: The authors declare that they have no competing interests., (© 2023 Baltzegar and Gould.)

Scolytus unicornis, a new species of Scolytus Geoffroy from Yunnan, China, is described and illustrated. Three DNA barcoding sequences (COI, 28S, CAD) of this species are provided. The new species is distinguished from other Asian Scolytus species by the longitudinal wrinkles on the frons only in the area below the eyes, a large median spine situated in the middle of the ventrite 2 base, and female frons with a slightly raised blunt tubercle above the epistoma.

In the United States, allyl isothiocyanate (AITC) has been registered as an insecticide, bactericide, and nematicide. And it has been confirmed that AITC has significant insecticidal activities against four stored product pests including Sitophilus zeamais Mostchulky (Coleoptera: Curculionidae). This study aimed to verify the mechanism of action of AITC on cytochrome c oxidase core subunits II in S. zeamais. Enzyme - catalyzed reactions and Fourier transform infrared spectrometer (FTIR) analysis revealed that the expressed COX II proteins could competitively bind and inhibit the activity of COX II. Furthermore, molecular docking results showed that a sulfur atom of AITC could form a 2.9 Å hydrogen bond with Ile-30, having a binding energy of -2.46 kcal/mol., Competing Interests: Declaration of Competing Interest None., (Copyright © 2023. Published by Elsevier Inc.)

Nutritional symbioses between insects and intracellular bacteria (endosymbionts) are a major force of adaptation, allowing animals to colonize nutrient-poor ecological niches. Many beetles feeding on tyrosine-poor substrates rely on a surplus of aromatic amino acids produced by bacterial endosymbionts. This surplus of aromatic amino acids is crucial for the biosynthesis of a thick exoskeleton, the cuticle, which is made of a matrix of chitin with proteins and pigments built from tyrosine-derived molecules, providing an important defensive barrier against biotic and abiotic stress. Other endosymbiont-related advantages for beetles include faster development and improved fecundity. The association between Sitophilus oryzae and the Sodalis pierantonius endosymbiont represents a unique case study among beetles: endosymbionts undergo an exponential proliferation in young adults concomitant with the cuticle tanning, and then they are fully eliminated. While endosymbiont clearance, as well as total endosymbiont titer, are host-controlled processes, the mechanism triggering endosymbiont exponential proliferation remains poorly understood. Here, we show that endosymbiont exponential proliferation relies on host carbohydrate intake, unlike the total endosymbiont titer or the endosymbiont clearance, which are under host genetic control. Remarkably, insect fecundity was preserved, and the cuticle tanning was achieved, even when endosymbiont exponential proliferation was experimentally blocked, except in the context of a severely unbalanced diet. Moreover, a high endosymbiont titer coupled with nutrient shortage dramatically impacted host survival, revealing possible environment-dependent disadvantages for the host, likely due to the high energy cost of exponentially proliferating endosymbionts. IMPORTANCE Beetles thriving on tyrosine-poor diet sources often develop mutualistic associations with endosymbionts able to synthesize aromatic amino acids. This surplus of aromatic amino acids is used to reinforce the insect's protective cuticle. An exceptional feature of the Sitophilus oryzae / Sodalis pierantonius interaction is the exponential increase in endosymbiotic titer observed in young adult insects, in concomitance with cuticle biosynthesis. Here, we show that host carbohydrate intake triggers endosymbiont exponential proliferation, even in conditions that lead to the detriment of the host survival. In addition, when hosts thrive on a balanced diet, endosymbiont proliferation is dispensable for several host fitness traits. The endosymbiont exponential proliferation is therefore dependent on the nutritional status of the host, and its consequences on host cuticle biosynthesis and survival depend on food quality and availability.

The maize weevil, Sitophilus zeamais, is a ubiquitous pest of maize and other cereal crops worldwide and remains a threat to food security in subsistence communities. Few population genetic studies have been conducted on the maize weevil, but those that exist have shown that there is very little genetic differentiation between geographically dispersed populations and that it is likely the species has experienced a recent range expansion within the last few hundred years. While the previous studies found little genetic structure, they relied primarily on mitochondrial and nuclear microsatellite markers for their analyses. It is possible that more fine-scaled population genetic structure exists due to local adaptation, the biological limits of natural species dispersal, and the isolated nature of subsistence farming communities. In contrast to previous studies, here, we utilized genome-wide single nucleotide polymorphism data to evaluate the genetic population structure of the maize weevil from the southern and coastal Mexican states of Oaxaca and Chiapas. We employed strict SNP filtering to manage large next generation sequencing lane effects and this study is the first to find fine-scale genetic population structure in the maize weevil. Here, we show that although there continues to be gene flow between populations of maize weevil, that fine-scale genetic structure exists. It is possible that this structure is shaped by local adaptation of the insects, the movement and trade of maize by humans in the region, geographic barriers to gene flow, or a combination of these factors., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Baltzegar et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

This study, about RPW and date palms, is under the scope of date palm bioecology and nutrition (nutritional ecology) which includes the integration of several areas of research such as date palm biochemistry, genetics, and RPW infestation behavior through various date palm cultivars. Date palm (Phoenix dactylifera L.; Arecaceae) production is under threat from the red palm weevil (RPW), Rhynchophorus ferrugineus Oliver. A better understanding of genetic diversity within date palm cultivars can be useful for its implementation within the insect IPM program in the future. Three indices, namely simple-sequence repeats (SSR) markers to elucidate genetic diversity, chemical components, and a natural infestation index of RPW, were used to evaluate the resistant or susceptible date palm cultivars in Qassim. Based on a field survey of RPW infestation within 79 date palm farms involving 11 cultivars at Qassim, the sensitivity and resistance cultivars were determined. The resistant date palm cultivars were Nabtat Ali, Shakrah, red Sukary, and um Kobar which had the lowest degree of RPW abundance %. Values of the essential minerals, nitrogen, phosphorus, potassium, and calcium within the date palm cultivars were also estimated. RPW abundance % was negatively correlated with the calcium content of date palm cultivars. The principal component analysis (PCA) revealed that the calcium content and RPW abundance % were highly affected by the cultivars. SSR markers of the date palm cluster tree divided genotypes into two main groups at similarity coefficients between 0.56 and 0.91. The 1st group included; Nabtet Ali, Red Sukary, Um Kobar, and Shakrah with similarity coefficients between 0.56, this group was the most resistant cultivars. Therefore, SSR markers were able to characterize and resolve genetic diversity in date palm cultivars for RPW resistance. When SSR markers coupled with higher calcium (Ca) content can efficiently replace indices in characterizing resistant date-palm genotypes with a high confidence level. Integration between date palm genetic diversity, chemical structures, and RPW infestations rates promoted the understanding of the interplay between the diversity of RPW management (short-time scale), and the resistance genes, plant nutrition, and dynamics of the diversity of RPW through domestication and diversification (long-timescale). Therefore, our results may lead to a change in RPW control strategies by switching to using safe alternative pesticide control methods (Resistant cultivars of date palm), which are underestimated and may reveal the impact of low-cost, but highly effective agricultural practices in the field of date production in the world. Understanding the genetic structure and calcium content of date palm cultivars mechanisms could help to predict date palm resistance against RPW populations in the new IPM strategy in RPW control.

Objective: Insect pests can cause severe losses in oilseed rape yields across Europe. Genomic and transcriptomic information is very limited for these insects. The aim of our study was to provide transcriptomic resources on several oilseed rape herbivores that will support research into their biology and help develop new methods of sustainable pest management., Data: Transcriptomes for larval stages of five major European pest species were de novo assembled by Trinity assembler. Total number of transcripts ranged from 112,247 for Ceutorhynchus pallidactylus to 225,110 for Ceutorhyncus napi. Intermediate numbers of 140,588, 140,998 and 144,504, were found for Psylliodes chrysocephala, Dasineura brassicae, and Brassicogethes aeneus, respectively. Bench-marking universal single-copy orthologues analyses for each dataset indicated high degree of completeness for all five species. The transcriptomes extend the list of genomic data on insect larvae that constitute major pests of oilseed rape. The data provide information on larval physiology and form a basis to develop highly specific RNA interference-based plant protection., (© 2023. The Author(s).)