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The green bug Apolygus lucorum is a notorious pest that feeds on multiple crops, including fruit trees, vegetables, and cotton. The odorant-binding proteins (OBPs) are considered to perform crucial roles in regulating A. lucorum behaviors such as mating and feeding. In this study, we first identified OBPs in the A. lucorum genome. Then, we calculated the expression levels of these OBP genes in different tissues and stages. Thereafter, we conducted ligand-binding assay to test the interactions between nine selected AlucOBPs and multiple chemical compounds. The result showed that there were 31 OBP genes encoding 39 transcripts in the A. lucorum genome, and several OBP clusters were found. Comprehensive expression profiling revealed the tissue-specific expression of some OBP genes. The results of fluorescence competitive binding assays showed that these nine AlucOBPs could specifically bind to plant volatiles, nonvolatile compounds, and synthetic analogs thereof. Additionally, AlucOBP19 was suggested to function in gustatory sensing to avoid deleterious plant secondary metabolites, as AlucOBP19 showed high expression in the mouthparts and legs and could interact with quercetin. Our findings highlight the potential biotechnological application of plant volatiles and their synthetic analogs as ecological attractants and provide new gene targets for control of A. lucorum.

Insects provide critical ecosystem services such as biological pest control, in which natural enemies (NE) regulate the populations of crop-feeding herbivores (H). While H-NE dynamics are routinely studied at small spatiotemporal scales, multiyear assessments over entire agrolandscapes are rare. Here, we draw on 18-year radar and searchlight trapping datasets (2003–2020) from eastern Asia to (i) assess temporal population trends of 98 airborne insect species and (ii) characterize the associated H-NE interplay. Although NE consistently constrain interseasonal H population growth, their summer abundance declined by 19.3% over time and prominent agricultural pests abandoned their equilibrium state. Within food webs composed of 124 bitrophic couplets, NE abundance annually fell by 0.7% and network connectance dropped markedly. Our research unveils how a progressive decline in insect numbers debilitates H trophic regulation and ecosystem stability at a macroscale, carrying implications for food security and (agro)ecological resilience during times of global environmental change.

A total of 12 OBPs were identified in the antennae of ladybird

As an important class of chemosensory-associated proteins, odorant binding proteins (OBPs) play a key role in the perception of olfactory signals for insects. Parasitoid wasp Microplitis mediator relies on its sensitive olfactory system to locate host larvae of Noctuidae and Geometridae. In the present study, MmedOBP14, a male-biased OBP in M. mediator, was functionally investigated. In fluorescence competitive binding assays, the recombinant MmedOBP14 showed strong binding abilities to five plant volatiles: β-ionone, 3,4-dimethylacetophenone, 4-ethylacetophenone, acetophenone and ocimene. Homology modeling and molecular docking results indicated that the binding sites of all five ligands were similar and concentrated in the binding pocket of MmedOBP14. Except acetophenone, the remaining four ligands at 1, 10 and 100 μg/μL caused strong antennal electrophysiological responses in adults M. mediator, and males showed more obvious EAG responses to most ligands than females. In behavioral trials, males were attracted by low concentrations of MmedOBP14 ligands, whereas high doses of β-ionone and acetophenone had a repellent effect on males. Moreover, 1 μg/μL of 3,4-dimethylacetophenone showed the strongest attractiveness to female wasps. These findings suggest that MmedOBP14 may play a more important role in the perception of plant volatiles for male wasps to locate habitat, supplement nutrition and search partners.

Sex pheromones are deemed to play a significant role in sexual communication of most insects. Although many sex pheromone components in mirid bugs have been identified, the roles of odorant receptors in sex pheromone perception in Adelphocoris spp. (Hemiptera: Miridae) remain unknown so far. Here, AlinOR33, a candidate sex pheromone receptor in Adelphocoris lineolatus was functionally characterized. Phylogenetic analysis showed that AlinOR33 clustered with the sex pheromone receptor AlucOR4 fromApolygus lucorum. Quantitative real-time PCR measurement revealed that the expression of AlinOR33 increased gradually from nymph to adult stage and reached its peak in the antennae of 3-day-old mated male bugs. The subsequent in situ hybridization demonstrated that AlinOR33 was mainly expressed in sensilla trichoid on the antennae of A. lineolatus. In the two-electrode voltage clamp recordings, AlinOR33/AlinOrco was specifically tuned to four sex pheromone components including butyl butyrate, hexyl hexanoate, trans-2-hexenyl butyrate and hexyl butyrate, and especially most sensitive to the major component trans-2-hexenyl butyrate. After dsAlinOR33 injection, the electroantennogram responses of males to four sex pheromone components were reduced significantly (∼50%). Compared to control bugs, dsAlinOR33-injected male bugs almost lost behavioral preference for trans-2-hexenyl butyrate. Furthermore, the wingbeat frequency of dsAlinOR33-injected male bugs notably declined. Therefore, we conclude that as a candidate sex pheromone receptor, AlinOR33 plays essential roles in the sexual behavior of A. lineolatus.

Plant volatiles such as floral scent compounds play a crucial role in mediating insect host locating, mate search, and oviposition sites selection. The alfalfa plant bug, Adelphocoris lineolatus (Goeze), is a seriously polyphagous herbivore of alfalfa and cotton that has an obvious preference for flowering host plants. In this study, we focused on the role of an odorant receptor AlinOR59 in the perception of plant volatiles in A. lineolatus. In situ hybridization showed that AlinOR59 was coexpressed with the coreceptor AlinORco in the ORNs cell located in the long curved sensilla trichodea on antennae of both genders. The Xenopus oocytes expression coupled with two-electrode voltage clamp recordings demonstrated that AlinOR59 responded to 15 plant volatiles. In electroantennogram assays, all of the above 15 compounds could excite electrophysiological responses in the antennae of adult bugs. Furthermore, an important floral scent compound, methyl salicylate, was utilized to evaluate the behavioral responses of A. lineolatus. It was found that adult bugs of both genders were significantly attracted to methyl salicylate. Taken together, our findings suggest that AlinOR59 plays a crucial role in the perception of floral scents in A. lineolatus and could be used as a potential target to design novel olfactory regulators for the management of bugs.

MicroRNAs (miRNAs), a class of non-coding single-strand RNA molecules encoded by endogenous genes, are about 21-24 nucleotides long and are involved in the post-transcriptional regulation of gene expression in plants and animals. Generally, the types and quantities of miRNAs in the different tissues of an organism are diverse, and these divergences may be related to their specific functions. Here we have identified 296 known miRNAs and 46 novel miRNAs in the antennae of the parasitoid wasp Microplitis mediator by high-throughput sequencing. Thirty-three miRNAs were predicted to target olfactory-associated genes, including odorant binding proteins (OBPs), chemosensory proteins, odorant receptors (ORs), ionotropic receptors (IRs) and gustatory receptors. Among these, 17 miRNAs were significantly highly expressed in the antennae, four miRNAs were highly expressed both in the antennae and head or wings, while the remaining 12 miRNAs were mainly expressed in the head, thorax, abdomen, legs and wings. Notably, miR-9a-5p and miR-2525-3p were highly expressed in male antennae, whereas miR-1000-5p and novel-miR-13 were enriched in female antennae. The 17 miRNAs highly expressed in antennae are likely to be associated with olfaction, and were predicted to target one OBP (targeted by miR-3751-3p), one IR (targeted by miR-7-5p) and 14 ORs (targeted by 15 miRNAs including miR-6-3p, miR-9a-5p, miR-9b-5p, miR-29-5p, miR-71-5p, miR-275-3p, miR-1000-5p, miR-1000-3p, miR-2525-3p, miR-6012-3p, miR-9719-3p, novel-miR-10, novel-miR-13, novel-miR-14 and novel-miR-28). These candidate olfactory-associated miRNAs are all likely to be involved in chemoreception through the regulation of chemosensory gene expression in the antennae of M. mediator.

Olfaction-based strategies have been successfully applied to monitor the emerald ash borer Agrilus planipennis Fairmaire (Coleoptera: Buprestidae); however, roles of chemosensory-associated proteins in olfactory perception of A. planipennis are rarely reported. Here, we identified 11 odorant-binding proteins (OBPs) from the A. planipennis transcriptome and genome. Sequence and phylogenetic analyses revealed that A. planipennis OBPs (AplaOBPs) could be classified into four subfamilies. The reverse transcription PCR (RT-PCR) analysis showed that all three members of the ABPII, one plus-C OBP, and one minus-C OBP were specifically or predominantly expressed in the antennae of both sexes, indicating their possible involvement in chemoreception. Subsequently, an antenna-specific OBP, AplaOBP1, was investigated through in situ hybridization, immunocytochemistry, and fluorescent competitive binding assays. It was found that the AplaOBP1 gene was detected under the base of the antennal sensilla, and the AplaOBP1 protein was expressed in the lymph of multiparous sensilla basiconica types I and III. In vitro, recombinant AplaOBP1 exhibited high binding affinities (Ki = 3.38–9.25 μM) with nine volatiles including five host-tree terpenes (e.g., myrcene, limonene, nerolidol, α-farnesene, and ocimene), which indicated that AplaOBP1 might be involved in the detection of host volatiles. The electrophysiological activities of all AplaOBP1 ligands were further confirmed using electroantennography, whose results imply that these volatiles may act as putative semiochemicals for A. planipennis. In conclusion, our results provide valuable insights into the molecular basis of olfaction in A. planipennis and help us use OBPs as targets to design novel olfactory regulators for management of A. planipennis.

MicroRNAs (miRNAs) are a class of small non-coding RNAs, which function as regulators of gene expression and contribute in numerous physiological processes. However, little is known referring to miRNAs function in insect chemosensation. In the current study, nine small RNA libraries were constructed and sequenced from the antennae of nymphs, adult males and females of Apolygus lucorum. In total, 399 miRNAs were identified including 275 known and 124 novel miRNAs. Known miRNAs were classified into 71 families, amongst which, 23 families were insect-specific. Expression profile analysis showed that miR-7-5p_1 was the most abundant miRNAs in the antennae of A. lucorum. Altogether, 69708 target genes related to biogenesis, membrane and binding activities were predicted for 399 miRNAs. Particularly, 15 miRNAs were found to target 16 olfactory genes. These miRNAs could be involved in regulation of olfactory-associated genes ex-pression. Comparing the antennae of nymphs, adult males and females, 94 miRNAs were found to be differentially expressed. The expression levels of some differentially expressed miRNAs measured by qPCR were consistent with sequencing results. This study provides a global miRNAs transcriptome in the antennae of A. lucorum and valuable information for further investigation on miRNA-mRNA interactions, especially the functions of miRNAs in regulating chemosensation.

BACKGROUND: The Apolygus lucorum is one of the most destructive insect pests in China with a wide range of host plants. Interaction of A. lucorum with surrounding environment heavily relies on chemical communication. Deorphanization of receptors involved in odors detection elevates our understanding of the olfactory system of this pest and may help to develop a chemical ecology‐based control strategy. RESULTS: AlucOR80, an odorant receptor (OR) in A. lucorum was newly cloned. Gene expression analysis showed that this receptor was mainly expressed in the antennae and head of both sexes but with a male bias. The Xenopus oocytes heterologous expression system coupled with the two‐electrode voltage‐clamp (TEVC) recording revealed that AlucOR80 was tuned to 21 selected compounds. Furthermore, electroantennogram (EAG) tests confirmed that all 21 ligands of AlucOR80 were electrophysiologically active in antennae of both sexes. Behavioral trials in a three‐cage olfactometer indicated that 16 compounds were behaviorally active, amongst which, 12 components were attractants and four components were repellents for adults of both sexes. Butyl butyrate and Dimethyl disulfide (DMDS) were the strongest attractive and repellant compounds, respectively. Importantly, we found the repellency of 1, 8‐Cineole, S‐(−)‐cis‐Verbenol and (1S)–(1)‐beta‐Pinene against adults of A. lucorum. CONCLUSION: Although AlucOR80 is a general OR, may play important role in the olfactory perception of A. lucorum. Screening of AlucOR80 ligands by behavioral assay provided valuable insights by which olfactory‐based management approaches could be developed by utilizing the behaviorally active components as attractants or repellents. © 2019 Society of Chemical Industry

The parasitoid wasp Microplitis mediator is an important natural enemy of the turnip moth Agrotis segetum and other Noctuidae pests. In our field observation, it was fortuitously discovered that sex pheromone traps used for A. segetum also attract female wasps, verified by a simulated field condition dual-choice laboratory assay. Therefore, it was hypothesized that olfactory recognition could be crucial in this process. In this regard, a female-biased odorant receptor of the wasp, MmedOR49, attracted our attention.To unravel the significance of the female-biased MmedOR49 regulating host pheromone recognition.Expression analysis (fluorescence in situ hybridization; quantitative realtime PCR), in vitro (two-electrode voltage-clamp recordings) and in vivo (RNAi combined with behavioral assessments) functional studies, and bioinformatics (structural modeling and molecular docking) were carried out to investigate the characteristics of MmedOR49.MmedOR49 expression was detected in the antennae of females by FISH. Quantification indicated that the expression level of MmedOR49 increased significantly after adult emergence. In vitro functional study revealed that MmedOR49 was specifically tuned to cis-5-decenyl acetate (Z5-10:Ac), the major sex pheromone component of A. segetum. Molecular docking showed that Z5-10:Ac strongly bound to the key amino acid residues His 80, Ile 81, and Arg 84 of MmedOR49 through hydrogen bonding. Behavioral assays indicated that female wasps were significantly attracted by Z5-10:Ac in a three-cage olfactometer. RNAi targeting further confirmed that MmedOR49 was necessary to recognize Z5-10:Ac, as female wasps lost their original behavioral responses to Z5-10:Ac after down-regulation of the MmedOR49 transcript.Although M. mediator is a larval endoparasitoid, female wasps have a behavioral preference for a sex pheromone component of lepidopteran hosts. In this behavior, for female M. mediator, MmedOR49 plays an important role in guiding the habitat of host insects. These data provide a potential target for enhancing natural enemy utilization and pest control.

Sex pheromones are deemed to play a significant role in sexual communication of most insects. Although many sex pheromone components in mirid bugs have been identified, the roles of odorant receptors in sex pheromone perception in

Sensory neuron membrane proteins (SNMPs), homologs of the human fatty acid transport protein CD36 family, are observed to play a significant role in chemoreception, especially in detecting sex pheromone in Drosophila and some lepidopteran species. In the current study, two full‐length SNMP transcripts, MmedSNMP1 and MmedSNMP2, were identified in the parasitoid Microplitis mediator (Hymenoptera: Braconidae). Quantitative real‐time polymerase chain reaction analysis showed that the expression of MmedSNMP1 was significantly higher in antennae than in other tissues of both sexes. In addition, the MmedSNMP1 transcript was increased dramatically in newly emerged adults and there were no significant differences between adults with or without mating and parasitic experiences. However, compared with MmedSNMP1, the expression of MmedSNMP2 was widely found in various tissues, significantly increased at half‐pigmented pupae stage and remained at a relatively constant level during the following developmental stages. It was found that MmedSNMP1 contained eight exons and seven introns, which was highly conserved compared with other insect species. In situ hybridization assay demonstrated that MmedSNMP1 transcript was distributed widely in antennal flagella. Among selected chemosensory genes (odorant binding protein, odorant receptor, and ionotropic receptor genes), MmedSNMP1 only partially overlapped with MmedORco in olfactory sensory neurons of antennae. Subsequent immunolocalization results further indicated that MmedSNMP1 was mainly expressed in sensilla placodea of antennae and possibly involved in perceiving plant volatiles and sex pheromones. These findings lay a foundation for further investigating the roles of SNMPs in the chemosensation of parasitoids.

Bee responses to floral scent are usually influenced by both innate biases and prior experience. Honeybees are less attracted than bumblebees to tomato flowers. However, little is known about how tomato floral scent regulates the foraging behaviors of honeybees and bumblebees. In this study, the foraging behaviors of the honeybee Apis mellifera and the bumblebee Bombus lantschouensis on tomato flowers in greenhouses were investigated. Whether the two bee species exhibit different responses to tomato floral scent and how innate biases and prior experience influence bee choice behavior were examined. In the greenhouses, honeybees failed to collect pollen from tomato flowers, and their foraging activities decreased significantly over days. Additionally, neither na&iuml, ve honeybees nor na&iuml, ve bumblebees showed a preference for tomato floral scent in a Y-tube olfactometer. However, foraging experience in the tomato greenhouses helped bumblebees develop a strong preference for the scent, whereas honeybees with foraging experience continued to show aversion to tomato floral scent. After learning to associate tomato floral scent with a sugar reward in proboscis extension response (PER) assays, both bee species exhibited a preference for tomato floral scent in Y-tube olfactometers. The findings indicated that prior experience with a food reward strongly influenced bee preference for tomato floral scent.

Plant volatiles such as floral scent compounds play a crucial role in mediating insect host locating, mate search, and oviposition sites selection. The alfalfa plant bug

The alfalfa plant bug Adelphocoris lineolatus (Goeze) (Hemiptera: Miridae), a serious pest of several agricultural crops, is extremely attracted by flowering plants to perform season host switching. Generally, chemoreception of A. lineolatus plays a crucial role in detecting food sources, locating mates and oviposition sites. In addition, odorant carrier proteins are believed to participate in the initial chemical communication and perception in insects. In this work, we identified 31 putative odorant carrier protein genes from the antennal transcriptomes of A. lineolatus, including 17 new odorant binding proteins (OBPs), 10 new chemosensory proteins (CSPs) and four Niemann-Pick type C2 proteins (NPC2s). Phylogenetic analysis demonstrated that the OBP and CSP genes from four mirid bug species (A. lineolatus, Adelphocoris suturalis, Apolygus lucorum and Lygus lineolaris) had a relatively close evolutionary relationship. Regular patterns and key conserved motifs of OBPs and CSPs in Hemiptera insects are also identified by using Multiple EM for Motif Elicitation (MEME) tool. Tissue expression profiles analysis showed that nine of the 17 OBPs, 10 CSPs and two of the four NPC2s were primarily or uniquely expressed in the adult antennae suggesting their putative roles in chemoreception. Our study provides the first insight into the roles of odorant carrier proteins in chemoreception of A. lineolatus, which will help to facilitate biological functions of odorant carrier proteins and develop novel insect behavioral regulation strategy in future.

The alfalfa plant bug Adelphocoris lineolatus, an economically important pest, has representative behavioral characteristics with host plants transfer. Olfactory system is essential for insects to perceive ever-changing chemical signals in the external environment, and chemosensory genes play crucial roles in signals reception and transduction. In this work, we compared the differences in chemosensory genes expression before and after host plants transfer by constructing 12 antennal transcriptomes of male and female bugs, respectively. The results showed that the expression levels of most chemosensory genes in A. lineolatus changed to adapt to the transformation of the hosts plant. More remarkable, female bugs had more up-regulated chemosensory genes than males. Differentially expressed genes (DEGs) analysis revealed three odorant binding proteins (OBPs), three chemosensory proteins (CSPs), eight odorant receptors (ORs) and one ionotropic receptor (IR) showed significant differences when the host plant transferred. There were complex characteristics of up- and down- regulated genes in male and female adults, among which OBP19 showed higher expression in females exposing to the new host plant alfalfa, suggesting this OBP may be associated with the localization of the oviposition site. The OR54 and OR82 were up-regulated in both genders, indicating their possible roles in recognizing some alfalfa-specific volatiles. These findings will provide valuable insights in biological functions of chemosensory genes in A. lineolatus and facilitate the development of new targets for novel strategies to control the alfalfa plant bug and other herbivores.

Apolygus lucorum (Hemiptera: Miridae), one of the main insect pests, causes severe damage in cotton and many other economic crops. As is well-known, legs play important roles in the chemoreception of insects. In this study, the putative chemosensory proteins in legs of A. lucorum involved in close or contact chemical communication of adult bugs were investigated using RNA transcriptome sequencing and qPCR methods. Transcriptome data of forelegs, middle legs and hind legs of adult bugs demonstrated that 20 odorant binding protein (OBP) genes, eight chemosensory protein (CSP) genes, one odorant receptor (OR) gene, one ionotropic receptor (IR) gene and one sensory neuron membrane protein (SNMP) gene were identified in legs of A. lucorum. Compared to the previous antennae transcriptome data, five CSPs, IR21a and SNMP2a were newly identified in legs. Results of qPCR analysis indicated that all these putative chemosensory genes were ubiquitously expressed in forelegs, middle legs and hind legs of bugs. Furthermore, four types of sensilla on legs of A. lucorum including sensilla trichodea (subtypes: long straight sensilla trichodea, Str1; long curved sensilla trichodea, Str2), sensilla chaetica (subtypes: sensilla chaetica 1, Sch1; sensilla chaetica 2, Sch2; and sensilla chaetica 3, Sch3), sensilla basiconca (subtypes: medium-long sensilla basiconca, Sba1; short sensilla basiconca, Sba2) and Bohm bristles (BB) were found using scanning electron microscopy. Additionally, the largest number of sensilla was observed on hind legs, while the forelegs had the smallest number of sensilla. Our data provide valuable insights into understanding the chemoreception of legs in A. lucorum.

Ionotropic receptors (IRs), as a member of the conserved chemoreceptor families in the peripheral nervous system , play a critical role in the chemoreception of Drosophila . However, little is known about IRs in Hymenoptera insects. Here, we comprehensively characterized the gene structure, topological map and chemosensory roles of antennal IRs (MmedIRs) in the hymenopteran parasitoid wasp Microplitis mediator . We found that the IRs were conserved across various insect species. In the in situ hybridization assays, most IRs showed female antennae biased features, and there was no co-expression of the IRs and the olfactory receptor co-receptor (ORco). Moreover, three IR co-expressed complexes, IR75u-IR8a, IR64a1-IR8a and IR64a2-IR8a, were detected. Two genes with high similarity, IR64a1 and IR64a2, were located in distinct neurons but projected to the same sensillum . In two-electrode voltage-clamp recordings, IR64a1 was widely tuned to the chemicals from habitat cues released from host plants over long distances, whereas IR64a2 responded to a narrow range host cues and plant odors with low-volatility. Notably, IR64a2 was able to perceive Z 9-14: Ald, a vital sex pheromone component that is released from Helicoverpa armigera , which is the preferred host of M. mediator. Furthermore, most ligands of IR64a1 and IR64a2 can trigger electrophysiological responses in female wasps . We propose that IR64a1 and IR64a2 collaboratively perceive habitat and host cues to assist parasitoids in efficiently seeking hosts.

Traps baited with female-produced sex pheromones have been very effective in the monitoring and management of mirid bugs in numerous field trials. However, none of the target odorant receptors for sex pheromone components in Apolygus lucorum have been identified. Here, we identified one candidate sex pheromone receptor, AlucOR4, from A. lucorum. Quantitative real-time PCR (qPCR) analysis revealed that AlucOR4 was antennae-enriched and male-biased in adult A. lucorum. Xenopus oocyte expression system assays demonstrated that AlucOR4/AlucOrco was sensitive to two major sex pheromone constituents and exhibited high sensitivity to (E)-2-hexenyl butyrate (E2HB) and lower sensitivity to hexyl butyrate (HB). The expression level of target mRNA was significantly reduced (>80%) in dsAlucOR4-injected bugs after five days. The electroantennogram (EAG) responses of male antennae to E2HB and HB were also reduced significantly (~40%). Our findings suggest that AlucOR4 is essential to sex pheromone perception in A. lucorum.

Odorant binding proteins (OBPs) and chemosensory proteins (CSPs) expressed in antennal chemosensilla are believed to be important in insect chemoreception. In the current study, we fully described the morphological characteristics of the antennal sensilla in parasitoid wasp Microplitis mediator and analyzed the expression patterns of OBPs and CSPs within the antennae. In M. mediator, eight types of sensilla were observed on the antennae. Sensilla basiconica type 2 and s. placodea with wall pores may be involved in olfactory perception, whereas s. basiconica type 1 and type 3 with tip pores may play gustatory functions. Among the 18 OBPs and 3 CSPs in M. mediator, 10 OBPs and 2 CSPs were exclusively or primarily expressed in the antennae. In situ hybridization experiments indicated that the 12 antennae-enriched OBPs and CSPs were mapped to five morphological classes of antennal sensilla, including s. basiconica (type 1–3), s. placodea and s. coeloconica. Within the antennae, most of OBP and CSP genes were expressed only in one type of sensilla indicating their differentiated roles in detection of special type of chemical molecules. Our data will lay a foundation to further study the physiological roles of OBPs and CSPs in antennae of parasitoid wasps.

Nine herbivore-induced plant volatiles (HIPVs) and one methyl jasmonate were field-tested for their attractiveness to the main predators in cotton fields of North China in 2 yr. The main predators including ladybird beetles (Propylaea japonica (Thunberg), Harmonia axyridis (Pallas)), green lacewings (Chrysoplera sinica (Tjeder), Chrysopa spp.), predatory bugs (Geocoris pallidipennis (Costa), Orius spp., Nabis spp.) and spiders (Misumenops tricuspidatus (Fabricius), Erigonidium graminicolum (Sundevall)) were investigated. Two-way ANOVA indicated that the volatile compound, year, and the volatile compound × year interaction affected the behavioral responses of predators. It was found that indole significantly attracted the ladybird beetle P. japonica, H. axyridis. Linalool could attract P. japonica. Green lacewing C. sinica was significantly attracted by α-pinene and β-pinene, whereas indole significantly attracted Chrysopa spp. Methyl jasmonate and α-pinene showed significant attraction to small-flower bug Orius spp. In addition, the attraction of α-humulene to C. sinica, attractiveness of β-pinene to Orius spp. and Chrysopa spp., were observed only in one of the two years. However, the big-eyed bug G. pallidipennis, damsel bug Nabis spp., spiders M. tricuspiata and E. graminicolum did not respond to any of the tested HIPVs. These results are discussed with respect to possible applications of a synthetic attractant for main predators in cotton fields.

Insect odorant binding proteins (OBPs), one of the most important groups of odor carriers, are believed to play essential roles in chemoreception. In the present study, we focused on AfasOBP11 in Adelphocoris fasciaticollis. Expression profiles showed that AfasOBP11 was mainly expressed in the mouthparts of A. fasciaticollis. Additionally, two types of sensilla, sensilla trichodeum and sensilla basiconicum, were found on the mouthparts of bugs. Moreover, anti-AfasOBP11 antiserum strongly labeled the sensilla basiconica. In fluorescence binding assays, recombinant AfasOBP11 displayed much stronger binding abilities to non-volatile secondary metabolite compounds than to volatile odors, suggesting a role of AfasOBP11 in taste sensing. To further investigate the biological functions of AfasOBP11, the feeding behavior of wild-type, dsGFP-injected and dsAfasOBP11-injected bugs was evaluated by performing electrical penetration graph (EPG) tests. After RNA interference of target AfasOBP11, A. fasciaticollis bugs spent a longer time and pierced more frequently on the artificial diet containing 2.0% gossypol, indicating that RNAi treated bugs reduced sensitivity to gossypol. Our findings suggest that AfasOBP11 may play a vital role in chemoreception of A. fasciaticollis, especially in gustatory perception.

In this study, the insecticidal effect of Poppy (Papaver somniferum) seed oil was investigated against Callosobruchus maculatus (Bruchidae) in cowpea, at different concentrations and exposure time. The Poppy seed oil at 2, 4, 6, 8 and 10 ml/kg was tested against adults of C. maculatus, and the mortality was counted after 24, 48 and 72 h of exposure. All tests were conducted at 27–30 °C and 65 ± 5% r.h. The experiments were carried out based on the factorial experiment by randomized complete design with four replications. Twenty-five insects with 0–24 h old were used for each replication. The effect of Poppy seed oil on the reduction of emergence of insects in next generation (F1) was also assayed. The results of experiments indicate the significant differences between concentrations and exposure time (p

The essential oil of Tanacetum balsamita L. was tested against Callosobruchus maculatus F. at the rates of 5.12, 7.23, 10.19, 14.36 and 20.24 μl/l air for adults and 5.3, 8.5, 10.8, 13.7 and 17.4 μl/l air for eggs. All experiments were conducted at 27 ± 1 °C and 65 ± 5% relative humidity. Mortality was counted after 24, 48 and 72 h of exposure and all adults (dead and alive) were taken out of the vials and the vials were left at the same conditions for further 35 days to assess progeny production. For mortality of eggs, unhatched eggs were counted after 7 days. The adults treated with oil were more susceptible than eggs. At highest dose (20.24 μl/l air) mortality of adults after 72 h, received 75.2%, but this amount for egg at 17.4 μl/l air after 72 h was 49.06%. The lowest LC50 value on 72 h was observed in adults (1.96 μl/l air). Also, the lowest LC95 value on 72 h was observed in adults (42.86 μl/l air). The percentage of reduced progeny on 72 h was 50.92% at 20.24 μl/l air. Our results suggest that T....

Virulence of three indigenous Iranian isolates of the fungus, Metarhizium anisopliae (Metsch.)Sorokin (Deuteromycotina: Hyphomycetes), named DEMIOO1, IRAN 715C and IRAN 1018C, were evaluated aswell as their virulence and their ability to suppress populations of the granary weevil, Sitophilus granarius L.(Coleoptera: Curculionidae). Five aqueous suspensions were prepared from each isolates, in a logarithmic seriesin Tween 80 (0.05% v/v). L'L, values ranged from 5.54 to 7.9 days following immersion in aqueous suspensions.Lowest LC so on day 10 was 114 X 10 5 conidia mL -1 for DEMIOO1.Cumulative mortality 10 days after treatmentvaried from 9.4 to 88.88% for IRAN 1018C at low and high concentration, respectively. Key words: Sitophilus granarius, Metarhizium anisopliae, immersion bioassay, Iranian isolates, pathogenicity INTRODUCTION The granary weevil Sitophilus granarius (L.) (Coleoptera: Curculionidae) is a very serious primary pestof stored grain products, which is able to causeconsiderable economic losses (Hill, 1990). Application ofinsecticides is one means of preventing some lossesduring storage. However, the choice of insecticides forstorage pest control is very limited because of the strictrequirements imposed for the safe use of syntheticinsecticides on or near food (Padin

Laboratory bioassays were conducted to determine the effect of food source on the survival of Tribolium castaneum Herbst, Oryzaephilus surinamensis L. and Rhyzopertha dominica F., after exposure to five diatomaceous earth (DE) formulations: Protect-It ® , Insecto ® , Perma-Guard TM , Dryacide ® and SilicoSec ® . Adults of these species were exposed to DEs at the rate of 0.5 mg/cm 2 for 1 day on filter paper inside plastic Petri dishes. After exposure, the initial mortality was counted and live individuals of the three species were held for a week in glass vials containing 50 mg wheat flour, rice and whole wheat, respectively. In the second experiment, after 1 day exposure to DEs, beetles were transferred to Petri dishes without food and held for a week to determine if the presence of food source would decrease the mortality of beetles. Experiments were carried out at 27 o C and 55% RH in the dark. The initial mortality in both of the experiments reached 100% for the three species exposed to Protect-It ® and in the case of R. dominica and O. surinamensis exposed to Dryacide ® . In contrast, low level of mortality (< 10%) was observed for T. castaneum exposed to Perma-Guard TM and Insecto ® . The mortality after the post-treatment period on food was decreased for the three species exposed to Perma-Guard TM and in the case of T. castaneum and R. dominica exposed to Insecto ® and SilicoSec ® . Adults of O. surinamensis were the most susceptible followed by R. dominica and 100% adult mortality was obtained, whereas T. castaneum were the least susceptible beetles to DEs. Protect-It ® and Dryacide ® were the most efficient DE formulations and can be used effectively in a stored grain integrated pest management program.

The insecticidal efficacy of five diatomaceous earth (DE) formulations, Protect-It®, SilicoSec®, Insecto®, Perma-Guard™ D-10 and Dryacide® was evaluated against adult Tribolium castaneum Herbst, the red flour beetle, on three oilseeds: safflower, sunflower and sesame. The DE formulations were applied at three rates: 0.5, 1 and 1.5 g/kg. The experiment was carried out at 26°C and 55 (±5)% RH in the dark. The mortality of T. castaneum adults was measured after 3, 7, 14 and 21 days exposure. After the 21-day mortality count, all surviving insects were removed and the samples retained under the same conditions for a further 45 days to assess progeny production (F1). Significant differences were recorded among the three oilseed types as well as between the DE formulations tested. After 21 days exposure, even at the lowest treatment rate, adult mortality was high (>90%) in safflower for all DE formulations. In contrast adult mortality was significantly lower in the case of sesame. Increased application rates improved the efficacy of DEs in sunflower and sesame. Even at the lowest rate the complete suppression in progeny production was achieved on treated safflower. The greatest number of progeny was recorded for treated sunflower seeds. Protect-It® and Dryacide® were the most efficient DE formulations against T. castaneum.

The susceptibility of adults of Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) and Oryzaephilus surinamensis L. (Coleoptera: Silvanidae) to three Iranian Isolates of the entomopathogenic fungi Metarhizium anisopliae (Metsch.) Sorokin was evaluated through bioassays with direct immersion under laboratory conditions. For each isolates, five aqueous suspensions were prepared in a logarithmic series in Tween 80 (0.05% v/v). Results showed that adult of both species were susceptible to all isolates of M. anisopliae. For all three isolates, mortality percentage of the two species increased with increasing conidial concentration and significant difference was observed between concentrations. The corrected cumulative mortality of adult of O. surinamensis 10 days after immersion ranged from 12.38 to 85.84%, 18.6 to 62.83% and 10.63 to 77.87% for different concentrations of DEMI001, IRAN 715C and IRAN 1018C, respectively. These amounts for T. castaneum varied from 31.07 to 74.78%, 26.02 to 75.61% and 23.33 to 89.99% for different concentrations of DEMI001, IRAN 715C and IRAN 1018C, respectively. The parameters of probit analysis demonstrated non-overlap of 95% confidence limits of LC50 and LC95 and significant difference was observed among three isolates tested against each insect. The lowest and the highest LC50 and LC95 values were observed in the isolates DEMI001 for O. surinamensis (3/1×105 and 1/5×108) and IRAN 715C for T. castaneum (6.2×108 and 6.9×1014), respectively. This observation highlights the importance and need of screening for more virulent isolates against storage pests for use in the management of these pests.

Effectiveness of spinosad dust formulation, that contains 0.125% spinosad, was evaluated against adults Callosubruchus maculatus (F.) on four commodities: chickpea, split pea, cowpea and lentil. Spinosad was applied at three dose rates: 0.1, 0.2 and 0.3 g/kg, corresponding to 0.125, 0.25 and 0.375 mg/kg of the active ingredient, respectively. The experiment was carried out at 27°C and 55±5% relative humidity. Adults mortality was measured after 1, 2, 5 and 10-days of exposure. After the 10-day mortality count, all surviving insects were removed and samples retained under the same conditions for a further 35 days to assess progeny reduction. Mortality of exposed individuals in all treated commodities was low at 1-day exposure even at 0.3 g/kg and did not exceed 20%. As expected, mortality increased with the increase of exposure interval and dose rates. A significant difference was observed among the four commodities. After 10 days of exposure, mortality reached 100% in all commodities except for split pea. The application of spi- nosad significantly reduced progeny production in four commodities tested in comparison with the untreated ones. High reduction in progeny production was recorded when spinosad was applied at the rate of 0.3 g/kg on split pea and cowpea (94.33 and 94.21%, respectively). The results of our study clearly revealed that spinosad dust could be successfully used as a grain protectant against C. maculatus. Further experimentations still need to be done to examine higher dose rates and long-term use in different commodities.

The insecticidal effect of spinosad dust, a formulation that contains 0.125% spinosad, was evaluated against adults of Tribolium castaneum (Herbst) on 4 commodities: safflower, sunflower, sesame, and canola. Fifty grams of each commodities were treated with 3 doses of the formulation: 100, 200, and 300 ppm, (corresponding to 0.125, 0.25, and 0.375 mg kg-1 a.i., respectively) at 27 °C and 60 ± 5% relative humidity. The mortality of T. castaneum adults was measured after 1, 2, 7, 14, and 21 days of exposure. After the mortality count on day 21, all surviving insects were removed while the samples were kept under the same conditions for a further 45 days to assess progeny production. The number of emerged individuals (adults and immatures) was then counted as progeny production. The increase of dose and exposure interval increased mortality. Significant differences were recorded among the 4 oilseed types and the mortality of T. castaneum on sesame was significantly lower compared to the other commodities. After 21 days of exposure, mortality reached 100% only on safflower at the highest dose (300 ppm). Progeny production was significantly lower on all 4 treated commodities in comparison with the untreated ones. Complete suppression in progeny production was achieved on safflower and sesame only at 300 ppm. In conclusion, our research revealed that application of spinosad dust formulation at higher rates and for longer exposure intervals could control T. castaneum in different oilseeds.