Search Results (111)

Chemosensory systems play a pivotal role in insect survival and reproduction by mediating the detection of volatile organic compounds in the environment. Protaetia brevitarsis (Coleoptera: Scarabaeidae), a phytophagous pest widely distributed across East Asia, poses a significant threat to agro-horticultural systems through crop damage. We conducted antennal transcriptome sequencing of adult beetles and identified 117 chemosensory-related genes, including 66 odorant receptors (ORs), 20 ionotropic receptors, 10 gustatory receptors, 13 odorant-binding proteins (OBPs), four chemosensory proteins, and four sensory neuron membrane proteins. Tissue-specific expression profiling revealed the antennal enrichment of five PbreOBP genes and twenty-three ORs. Notably, sexual dimorphism was observed in OR expression patterns. PbreOR1/6/17/18/21/22/30/32 exhibited male-biased antennal expression, whereas PbreOR25/26/29/38/41/44/61 demonstrated female-biased antennal expression, indicating their potential involvement in sex-specific behaviors, such as pheromone detection and oviposition site selection. A comprehensive description of the antenna chemosensory-related genes of P. brevitarsis has deepened our understanding of the olfactory mechanisms in coleopteran insects. This study also provides a basis for understanding the molecular mechanisms underlying olfaction in P. brevitarsis. Full article

Experiments were conducted to examine whether the abdominal glands of Cynops ensicauda subspecies (C. e. ensicauda and C. e. popei) express different mRNAs for sodefrin-like female-attracting pheromone precursors. A precursor mRNA encoding a novel sex pheromone candidate, [Gln⁸]sodefrin, was widely detected in the abdominal glands of both of C. ensicauda subspecies. Female partners exhibited a considerable preference for synthetic [Gln⁸]sodefrin. Thus, [Gln⁸]sodefrin was designated caudarin. In C. e. ensicauda, the abdominal glands of males expressed sodefrin precursor mRNA as well, and sodefrin was also effective in attracting female partners. In addition to caudarin precursor mRNA, the abdominal glands of C. e. popei males expressed silefrin ([Leu³, Gln⁸]sodefrin) precursor mRNA, as reported previously. Moreover, imorin, a male-attracting pheromone previously identified in C. pyrrhogaster females, was effective in attracting C. e. ensicauda males but not males of C. e. popei. Molecular phylogenetic analysis indicated that trans-specific possession of sodefrin genes was likely because of gene occurrence preceding speciation of C. ensicauda and C. pyrrhogaster, and that the additional occurrence of silefrin in C. e. popei possibly resulted from duplication of the caudarin gene. Differences in pheromone components among Cynops species and subspecies reflect the speciation route estimated by previous molecular genetic analyses. Full article

Reported in Europe in the early 2000s, Delottococcus aberiae (De Lotto) (Hemiptera: Pseudococcidae) is an invasive mealybug pest that is causing severe damage to citrus production in eastern Spain. Once its main sex pheromone component was identified in a previous work as (4,5,5-trimethyl-3-methylenecyclopent-1-en-1-yl)methyl acetate 1, the revision of virgin female effluvia is here reported to improve knowledge about the biology of D. aberiae. A new minor component has been identified in the volatile samples collected from virgin females as ((1R, 4R)-3,4,5,5-tetramethylcyclopent-2-en-1-yl)methyl acetate (trans-α-necrodyl acetate, (1R, 4R)-2), a compound also found in the essential oil of Lavandula stoechas subsp. luisieri. Bioassay testing of the activity of this compound showed that a synthetic sample of the racemate (±)-(trans)-2 was attractive to D. aberiae males both in the laboratory and field but with a lower attractant power than enantiopure (1R, 4R)-2 and (±)-(1). The 1:1 mixture of (1R, 4R)-2 and (±)-1 provided a slight additive effect. Further trials are needed to know the pest control potential of this minor compound but the possibility of obtaining this substance from a natural source could pose an important advantage to implement new methods for the sustainable control of D. aberiae. Full article

Helopeltis cinchonae is an emerging pest of tea and causes severe damage to tea plantations in China. The female of H. cinchonae has been reported to produce a sex pheromone consisting of two components, hexyl (3R)-3-acetoxybutyrate and (5R)-1-acetoxy-5-butyroxyhexane, and lures containing the synthetic compounds have been shown to attract male H. cinchonae to traps in the field. This is the first time that components of the sex pheromone have been identified for a species of Helopeltis bug, but their field application has not been evaluated in detail. The present study shows that a blend of both compounds loaded into a polyethylene vial at 0.2 and 2 mg, respectively, caught significantly more male H. cinchonae bugs than the individual compounds and all the other tested blends. Sticky wing traps baited with the binary blend of compounds at the optimized ratio and dosage caught more bugs than bucket funnel or delta traps, and traps hung at a height of 10 cm above the tea shoots caught more bugs than those at other heights. The optimized traps and lures were used for monitoring the pest and two distinct population peaks of H. cinchonae were observed, the first one during mid-May to early June, and the other one in mid-September. Overall, the results of this study contribute to an environmentally-friendly approach to monitoring and managing H. cinchonae in the field. Full article

Female mating success for the tortricids codling moth (CM), Cydia pomonella, Oriental fruit moth (OFM), Grapholita molesta, European grape vine moth (EGVM), Lobesia botrana, and five leafroller (LR) species under various mating disruption (MD) programs was reviewed at a time when new dual sex lures can provide alternative tools to assess female mating. Previous reliance on passive assessments such as tethering and virgin female-baited traps with laboratory moths are at odds with active trapping methods of wild moths. Additive factors such as delayed mating, adjustments in female behaviors, and greater levels of natural control may or may not contribute to the apparent success of MD. Current MD programs are not based solely on research, as economics and commercialization require some compromise. The complete sex pheromone blend is not always used. A delay in mating has been reported from the field with one study and suggested that reductions in fecundity would likely be minimal. There is no evidence that MD works better with low population densities. MD is an established technology, but the new dual sex lures are showing that the density of mated females is rather high. Efforts to improve the efficacy of MD are ongoing with a small cadre of researchers. Full article

The tea tussock moth (Euproctis pseudoconspersa) is a common tea plantation pest with Type III sex pheromone components (SPCs). However, the olfactory genes involved in the perception of Type III SPCs remain unknown. To identify the olfactory genes involved in E. pseudoconspersa olfactory perception, we sequenced the transcriptomes of different tissues from male and female moths. We identified 27 chemosensory proteins, 39 odorant-binding proteins (OBPs), 28 ionotropic receptors (IRs), and 67 odorant receptors (ORs). Phylogenetic and antennal abundance analyses showed that EpseOR12, EpseOR13, EpseOR15, EpseOR16, and EpseOR18 belonged to the pheromone receptor clades of Type II moths, with predominant expression in male antennae. Besides these EpseORs, EpseOR14 and EpseOR32 were two of the most abundant EpseORs in male antennae, where they were predominantly expressed. Four pheromone-binding proteins (PBPs) were identified, with higher expression in male antennae. EpseORs and EpsePBPs may be involved in Type III SPC detection. Additionally, a few EpseOBPs, EpseIRs, and EpseORs were predominantly expressed in either male or female antennae. These genes may play important roles in olfaction and may be involved in detecting host plant volatiles and pheromones. These results provide a foundation for further exploration of the molecular mechanisms of E. pseudoconspersa olfaction. Full article

A four-component blend comprising pear ester, DMNT, linalool oxide, and acetic acid (CM4K) was identified as a potent allelochemical lure for both sexes of codling moth (CM), Cydia pomonella (L.). Studies conducted from 2020 to 2022 in Washington State (USA) examined factors which could impact the lure’s relative performance. The CM4K lure was effective across a range of mating disruption programs and was equally attractive in monitoring wild and sterile CM. The lure remained attractive for at least 10 weeks. Total catch in traps baited with the CM4K was significantly less impacted than a sex pheromone lure located near mating disruption dispensers and female catches were largely unaffected. Traps with the CM4K lure caught significantly more females and fewer males when placed near clusters of fruits in a trellised orchard. Two factors were found to significantly impact the relative performance of the CM4K to sex pheromone lures: the CM4K lure was only equivalent to sex pheromone lures in pear MD orchards, and apple and pear orchards with vigorous weed growth. This is the first report of a monitoring lure for a tortricid moth being negatively impacted by the background odor of non-host weed species present within an orchard. Full article

Insect sex pheromones have been widely used in integrated pest control due to their efficiency, non-toxicity, specificity, and environmental sustainability. They are considered a key component of green pest management techniques. Polymerus pekinensis is a phytophagous plant bug on alfalfa (Medicago sativa L.) in East Asia. This study used gas chromatography–electroantennogram detection (GC–EAD) and gas chromatography–mass spectrometry (GC–MS) to analyze the whole-body extracts from male and female P. pekinensis. Octyl acetate (OA) and decyl acetate (DA) elicited the antennal response of males and were identified as the predominant components of female and male extracts, respectively. Subsequent field trials demonstrated that OA (>8 mg per lure) showed the strongest attraction to conspecific males. However, when DA was added in a lure (≥2 mg), a significant decline in captures occurred. These findings provide new insights into the understanding of sex pheromones in Miridae and benefit the development of sustainable management of P. pekinensis. Full article

The poplar moth, Leucoptera sinuella (Lepidoptera: Lyonetiidae), is widely distributed across Europe, Asia, and parts of Africa. It was first identified in Chile in 2015 and has since become a significant pest in the agricultural sector. Additionally, economic losses are further aggravated by the presence of L. sinuella pupae in nearby fruit orchards. This study investigated the presence of a male-produced sex pheromone in L. sinuella, focusing on the hairpencil (HP) glands, which are known as dissemination structures for male pheromones in lepidopterans. Male HP glands were solvent-extracted and analyzed by gas chromatography–mass spectrometry. Chemical microderivatization and comparisons of mass spectra and retention indices of natural compounds with synthetic standards led to the identification of two compounds: (Z)-3-decenyl hexanoate (the major component) and (Z)-3-decen-1-ol (a minor component). Although electrophysiological assays did not show detectable antennal responses to (Z)-3-decenyl hexanoate, behavioral bioassays demonstrated its role as a short-range courtship signal in L. sinuella. Males with ablated hairpencils exhibited significantly reduced courtship success compared to controls; however, exposure of females to synthetic (Z)-3-decenyl hexanoate or HP extract restored male courtship success. To our knowledge, (Z)-3-decenyl hexanoate has not been previously reported as a sex pheromone component in any insect species, making this discovery an intriguing addition to the diversity of chemical communication in insects. Full article

The emerald ash borer (EAB), Agrilus planipennis Fairmaire, is an invasive forest pest that is causing a rapid decline in ash (Fraxinus spp.). As EABs spread across North America to 35 U.S. states and 5 Canadian provinces, detection of the pest has proven difficult, especially at low population density sites. Panel traps have been commonly used in detection and monitoring of EAB populations. Over two sampling periods from 2016 through 2019, adult catches and detection rates were compared among four combinations of panel trap color, lure, and crown placement in southern Arkansas, northern Louisiana, and eastern Texas. The four combinations were as follows: (1) dark purple baited with (Z)-3-hexenol alone in the mid–upper crown; (2) light green with (Z)-3-hexenol plus (3Z)-lactone in the mid–upper crown; (3) dark purple with (Z)-3-hexenol in the lower crown; and (4) dark purple with (Z)-3-hexenol plus (3Z)-lactone in the lower crown. Mid–upper tree crown placement, ~13 m, of panel traps were more effective for EAB detection and adult capture, especially of males. The sex pheromone (3Z)-lactone deterred females but attracted males, while (Z)-3-hexenol attracted females. The green panel trap with both lures and mid–upper crown placement did not drastically increase male catches, contrary to previous studies at low EAB densities. The use of (3Z)-lactone on dark purple traps at low crown placements, such as those used in the National Survey Program, is not recommended for EAB detection due to its repellent effect on EAB females. Full article

The pheromones of crane flies (Tipulidae), one of the largest families within the order Diptera (over 15,000 species), are unknown. The aim of our study was to identify the chemical compounds involved in communication in Tipula autumnalis, a representative species of the family. Female cuticular washes were found to be attractive to males in a bioassay. GC-EAD analysis revealed nine EAG-active compounds, which were identified as cuticular hydrocarbons (CHCs). Both males and females contained these CHCs, though in different ratios. The strongest antennal responses in male T. autumnalis were evoked by n-pentacosane, (Z)-9-pentacosene, and (Z, E)-6,9-pentacosadiene, which were the predominant components in females. Each of these compounds were attractive to males in the behavioral assay and are therefore attributed to the female sex pheromone of T. autumnalis. (Z)-9-tricosene and (R)-3-methylheneicosane elicited both EAG and behavioral responses in males and were abundant in washes from same-sex individuals. In addition to the compounds involved in female–male interactions, it is evident that T. autumnalis also employs CHCs in male–male interactions. The exact roles of some compounds remain undetermined. Among the semiochemicals, the established stereostructure of (Z, E)-6,9-pentacosadiene and the olfactory/behavioral effects of (R)- and (S)-3-methylheneicosane were novel findings in insects. Full article

Moths use pheromones to ensure intraspecific communication. Nevertheless, few studies are focused on both intra- and intersexual communication based on pheromone recognition. Pheromone-binding proteins (PBPs) are generally believed pivotal for male moths in recognizing female pheromones. Our research revealed that PBP1 of Agriphila aeneociliella (AaenPBP1) serves a dual function in both intra- and intersexual pheromone recognition. Here, a total of 20 odorant-binding protein (OBP) family genes from A. aeneociliella were identified and subjected to transcriptional analysis. Among these, AaenPBP1 was primarily highly expressed in the antennae. Competitive fluorescence binding assays and molecular docking analyses demonstrated that AaenPBP1 exhibits a strong binding affinity for the female sex pheromone (Z)-9-Hexadecenyl acetate and the male pheromone 1-Nonanal. Notably, hydrogen bonds were observed between Ser56 and the ligands. The analysis of pheromone components and PBPs in lepidopteran lineage suggested that their strong and precise interactions, shaped by coevolution, may play a crucial role in facilitating reproductive isolation in moths. Our findings provide valuable insight into the functional significance of PBPs in invertebrates and support the development of behavioral regulation tools as part of an integrated pest management strategy targeting crambid pests. Full article

During the spring–summer seasons between 2019 and 2023, in the localities of Maquehue (La Araucanía Region) and Llifén (Los Ríos Region), we collected 262 virgin Proholopterus chilensis (1 female/2.3 males) specimens emerging from the live trunks of N. obliqua trees, an atypical sex ratio in Cerambycidae, suggesting high male competition for females. Virgin specimens of both sexes were individually placed in panel traps in the field, capturing only males (n = 184) over the field study seasons and only in traps baited with females. This fact preliminarily suggests the P. chilensis females emit possible “volatile or airborne” pheromones (eventually being a long-range sex pheromone), something unusual in Cerambycinae, the subfamily to which it currently belongs, although the taxonomic status of the species is under debate. In Llifén and Santiago (Metropolitan Region), behavioral observations were conducted, which allowed us to define the conditions necessary for male–female encounters that were replicated when carrying out volatile captures (Head Space Dynamic = HSD) and collections of compounds from terminalias excised from females. In field trials, virgin females less than ten days old were more attractive than older ones and attracted males during the night, i.e., between 23:00 and 5:00 AM, when the ambient temperature exceeded 11.6 °C. The aeration of females under the conditions described above and subsequent analysis of extracts by GC-MS allowed the identification of compounds absent in males and the control, including two oxygenated sesquiterpenes, a nitrogenous compound (C₂₀), and a long-chain hydrocarbon (C₂₆). From the terminalia extracts, hentriacontane, heptacosane, and heneicosyl, heptacosyl and docosyl acetates were identified by GC-MS, and their roles are unknown in the development of short-distance sexual behaviors, but they could serve to mark a trail leading the male towards the female in the final stage of approach for courtship/mating. Thus, we proposed the hypothesis that P. chilensis females emit both a long-range and a trail-pheromone, which, if confirmed, would be a rare case in this family. The specific identity of the compounds obtained by HSD, as well as the activities of these chemicals and those obtained from the terminalias, should be evaluated in future behavioral studies, as well as regarding their potential to attract males under field conditions. The current document is the first report on volatiles obtained from aerations and compounds extracted from female terminalia in P. chilensis. Full article

The Indian meal moth, Plodia interpunctella, poses a significant threat to global agricultural products. Although pheromone-based technologies show promise for P. interpunctella management, limitations such as single-sex targeting necessitate exploring complementary strategies. Vegetable-based oils represent a potential alternative but their efficacy, sex-specificity, and interaction with sex pheromones remain unclear. To address these questions, we first examined the attraction of P. interpunctella female and male adults to 10 commercially available vegetable oils in semi-field conditions. Sesame, olive, and blended oils were the most attractive, capturing significantly more adults compared to other oils. We then evaluated the effectiveness of these three attractive oils and their combinations with P. interpunctella sex pheromones in a grain warehouse. Traps baited with these oils captured significantly more females and males compared to control traps without attractants; however, the addition of sex pheromones did not improve male capture and significantly reduced female capture, suggesting an inhibitory effect. Finally, we demonstrated that female mating status (mated vs. virgin) did not influence the attractiveness of traps baited with these effective oils. Our findings highlight the potential of standalone traps baited with blended, olive, or sesame oil as a practical, economic, and effective management strategy for P. interpunctella in storage facilities. Full article

The northern bark beetle, Ips duplicatus, is an emerging economic pest, reportedly infesting various species of spruce (Picea spp.), pine (Pinus spp.), and larch (Larix spp.) in Central Europe. Recent climate changes and inconsistent forest management practices have led to the rapid spread of this species, leaving the current monitoring strategies inefficient. As understanding the molecular components of pheromone detection is key to developing novel control strategies, we generated antennal transcriptomes from males and females of this species and annotated the chemosensory proteins. We identified putative candidates for 69 odorant receptors (ORs), 50 ionotropic receptors (IRs), 25 gustatory receptors (GRs), 27 odorant-binding proteins (OBPs), including a tetramer-OBP, 9 chemosensory proteins (CSPs), and 6 sensory neuron membrane proteins (SNMPs). However, no sex-specific chemosensory genes were detected. The phylogenetic analysis revealed conserved orthology in bark beetle chemosensory proteins, especially with a major forest pest and co-habitant, Ips typographus. Recent large-scale functional studies in I. typographus chemoreceptors add greater significance to the orthologous sequences reported here. Nevertheless, identifying chemosensory genes in I. duplicatus is valuable to understanding the chemosensory system and its evolution in bark beetles (Coleoptera) and, generally, insects. Full article