Adelphocoris Lineolatus Research Articles

MTCO1 Analysis of Mirids- <i>Adelphocoris Lineolatus</i> and <i>A Seticornis</i>

This article presents the results of study on the species Adelphocoris lineolatus (Goeze, 1778) and A. seticornis(Fabricius, 1775) belonging to the genus Adelphocoris (Reuter, 1896) collected from the Tashkent region andFergana Valley of our Republic during 2019-2023. The mtCO1 region of the mitochondrial DNA of thesespecies were analyzed and the phylogenetic relationships of the representatives of this genus were studied.

Diversity of True Bugs (Hemiptera: Heteroptera) on Common Ragweed (Ambrosia artemisiifolia) in Southern Slovakia

The common ragweed (Ambrosia artemisiifolia Linnaeus 1800) is an exceptionally invasive species. The information on true bugs occurring on ragweed plants is limited in the invasion region. The objective of this study was to determine the species composition of Heteroptera associated with A. artemisiifolia, to assess their vectoring potential based on a literature review, and to compare species similarity in the surveyed fields. Field surveys were conducted in 2020–2021 at 10 sites in southern Slovakia. Sweeping and visual observations were conducted in field margins, weedy agricultural fields, and mowed meadows infested with A. artemisiifolia. In the study, food specialization, the abundance of individual species, and their assignment to families were precisely determined. The Jaccard similarity index was used to evaluate similarities in species composition among the sites studied. A total of 2496 true bugs were recorded, representing 47 species of Heteroptera from 12 families. The most common phytophagous species were Nysius ericae ericae (Schilling, 1829) (Pentatomomorpha, Lygaeidae), Adelphocoris lineolatus (Goeze, 1778), Lygus rugulipennis (Poppius, 1911), Lygus pratensis (Linnaeus, 1758) (Cimicomorpha, Miridae), and a zoophagous species Nabis (Dolichonabis) limbatus (Dahlbom, 1851) (Cimicomorpha, Nabidae). The species similarities in pair-wise combined localities were low, with a dominance of highly migratory and polyphagous species able to traverse the field from the adjacent landscape. A. artemisiifolia is a known host for plant viruses and phytoplasmas, and several Heteroptera species are carriers of these plant pathogens. Halyomorpha halys was the only detected vector of phytoplasmas, and its abundance on A. artemisiifolia was extremely low.

Plant Bugs (Heteroptera: Miridae) Development and Damage to Cotton Crop in Uzbekistan

This article provides information on the types of plant bugs, their damage, and measures to combat them in cotton agrobiocenoses of Uzbekistan. As a result of the conducted research, 15 species of bugs, of which Eurystylus bellevoyei (Reuter, 1879) species were identified for the first time in the cotton fields of Uzbekistan. In special experiments in the cages, it was determined that when 100-150 bugs correspond to 100 cotton plants during the vegetation stage of the cotton plant, cotton yield decreases to 32.3-36.4% owing to the effect of alfalfa bug (Adelphocoris lineolatus) and 8.6-13.5% owing to the plant bug (Lygus. protensis). If cotton is infected with a cotton shredder bug (Creontiades pallidus) in the early period (June), the yield of cotton decreases from 61.6% to 88.9%, if there are 30 to 150 plant bugs per 100 cotton plants. If it is infected later (July-August), the yield of cotton decreases from 38.0 to 50.2%. If fine fiber cotton is damaged by bugs (100-150 specimens per 100 cotton plants) during the vegetation stage, the cotton yield will decrease by 55.5-65.3% compared to the control variant. The most effective drugs against plant bugs are: Safegor, 40% (98.3%), Ribo Super, 25% (93.4%), Transform, 50% (92.5%), and Mosetam 20 (82.8-81.9%). Arvilmek 1.8 (active substance- abamectin), Lead, 5% (substance-pymetrozine), Imido Star, 20% (imidacloprid) were found to have unsatisfactory (below 70.0%) results against cotton bugs.

Species of Mung Bean Main Pests of Second Sowing Date, Their Distribution

An overview of the species of the main pests of mung bean (Vigna radiata (L.) R. Wilczek) is given. The research was carried out in 2017-2019 in the fields of farms in the Tashkent region. Systematic analysis of species was carried out according to standard methods. Dispersion analysis of the obtained results was determined by the method of B. A. Dospekhov. 26 species of pests and 10 species of natural entomophages were identified, of which 5 species are the main ones (spider mites, turnip moth, cotton bollworm, alfalfa plant bug, southern cowpea weevil). The least damage to the culture is caused by 3 species of weevils: southern cowpea weevil (Callosobruchus maculatus (Fabricius, 1775)), pea weevil (Bruchus pisorum Linnaeus, 1758) and American seed beetle (Acanthoscelides obtectus (Say, 1831)). These pests infect mung bean culture up to 47.7-53.2%. The spider mite infects second sowing date mung bean twice as much as the main crop. The damage to the main crop amounted to 25.2-28.1%, and with the second sowing date — 48.1-49.7%. Based on the conducted research, it was concluded that the development of environmentally friendly, environmentally friendly methods of combating the main pests of mung bean in accordance with modern technologies is one of the most important tasks today.

Preliminary data on attractiveness of phenylacetaldehyde-based lures on economically important plant bug pests (Hemiptera: Miridae)

Several plant bug species (Miridae) are important pests of crops and vegetables, thus monitoring them is of essential importance for effective pest control. During the current, preliminary study synthetic plant volatile combinations were tested in field conditions in Hungary in alfalfa fields. Beside semiochemical baited traps, sweep-netting was also performed. In the experiments three plant bug species were found in higher numbers: Adelphocoris lineolatus, Lygus rugulipennis and L. pratensis. As a novel, interesting finding L. pratensis was attracted to phenylacetaldehyde baited traps. For all species, both males and females were trapped in all combinations. Sweep-netting and semiochemical baited traps showed different efficacy in case of the three species, as sweep-netting catches were highly biased for A. lineolatus, which indicates the higher efficacy of this method as compared to the tested semiochemical-baited traps. On the other hand, semiochemical baited showed better performance for L. rugulipennis and L. pratensis. For these species none of the tested combinations performed better than phenylacetaldehyde baited traps. The potential implication of results in view of monitoring are discussed.

Anti-pest protection of two-year old alfalfa grown for seeds

Purpose. To evaluate the effectiveness of different insecticides against pests on two-year old alfalfa grown for seeds.
 Materials and methods. The study was conducted in the experimental field of the Institute of Irrigated Agriculture of NAAS in 2017–2019. The filed experiments were laid out in split plots. The main plots (factor A) were for water supply conditions (no irrigation vs. irrigation); sub-plots (factors B and C) were for application of insecticides. Seeds were sown in wide rows with interrows of 70 cm.
 Results and discussion. When the two-year old alfalfa canopy (budding onset) was inspected before insecticide treatment, the average numbers of pests were as follows: alfalfa plant bug – 3.0 specimens/10 sweeps, alfalfa aphid – 20.0 specimens/10 sweeps, beet webworm – 3.0 specimens/10 sweeps, alfalfa weevil (imagoes/grubs) – 1.0/3.0 specimens/10 sweeps, and alfalfa seed weevil – 1.0 specimens/10 sweeps. Treatment 1 reduced the pest numbers in the canopy: alfalfa plant bug – by 70.0–93.3%, alfalfa aphid – by 93.0–97.5%, beet webworm – by 80.0–96.7, alfalfa weevil (imagoes/grubs) – by 60.0–90.0%/73.3–93.3%, and alfalfa seed weevil – by 76.0–94.0%, depending on the insecticide. Treatment 2 helped to reduce the pest numbers in the canopy. Insecticide containing active substances chlorpyrifos 500 g/L and cypermethrin 50 g/L applied at a dose of 1.00 L/ha was the most effective. The highest seed yield was achieved after treatment 1 with insecticide containing active ingredients chlorpyrifos 500 g/L and cypermethrin 50 g/L applied at a dose of 1.00 L/ha and treatment 2 with insecticide containing active ingredients chlorantraniliprole 200 g/L and lambda-cyhalothrin 50 g/L applied at a dose of 0.17 L/ha and 0.15 L/ha, respectively.
 Conclusions. The highest seed yield was achieved after treatment 1 with insecticide containing active ingredients chlorpyrifos 500 g/L and cypermethrin 50 g/L applied at a dose of 1.00 L/ha and treatment 2 with insecticide containing active ingredients chlorantraniliprole 200 g/L and lambda-cyhalothrin 50 g/L applied at a dose of 0.17 L/ha and 0.15 L/ha, respectively

Identification and functional characterization of sex pheromone receptors in mirid bugs (Heteroptera: Miridae)

Mirid bugs are a group of important insect pests that cause large annual losses in agricultural production. Many studies have focused on the isolation and identification of sex pheromones in mirid bugs, and the components and biological activity of the sex pheromones have also been studied as a way to control these pests. However, few studies have focused on the mechanisms of pheromone perception. In this study, we identified the odorant receptor repertoire in three mirid bug species, Apolygus lucorum, Adelphocoris lineolatus, and Adelphocoris suturalis using antennal transcriptome sequencing and bioinformatics analysis. The candidate pheromone receptor (PR) genes were then identified by comparative transcriptomic and expression pattern analysis. Importantly, in vitro functional studies have shown that the candidate PRs have robust responses to the main mirid bug sex pheromone components (E)-2-hexenyl butyrate (E2HB) and hexyl butyrate (HB). Our study uncovered the mechanism of pheromone peripheral coding in these three species and elucidated the mechanism by which mirid bugs can specifically recognize a mate. Moreover, the results of our study will provide a theoretical basis for screening effective sex attractants or mating disturbance agents at the molecular and neural levels for enhanced control of these destructive pests.

Functional Characterization of a Candidate Sex Pheromone Receptor AlinOR33 Involved in the Chemoreception of Adelphocoris lineolatus.

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.

OBP14 (Odorant-Binding Protein) Sensing in Adelphocoris lineolatus Based on Peptide Nucleic Acid and Graphene Oxide.

Simple SummaryThe alfalfa plant bug, Adelphocoris lineolatus (Goeze) (Hemiptera: Miridae), is a serious agricultural pest in China. Previous studies have shown that olfaction plays a crucial role in the survival and reproduction of herbivorous insects, such as A. lineolatus, and OBPs (odorant-binding proteins) are involved in the initial steps of olfaction. Due to the complex intracellular environment in insects, detection of the expression of OBP genes by conventional methods is limited in vitro. In this study, we developed a PNA-GO- (peptide nucleic acid and graphene oxide) based mRNA biosensor that allows detection of the expression of the AlinOBP14 gene in A. lineolatus. We demonstrate that AlinOBP14 is expressed in the adult head, which is consistent with previous research on the expression profiles of AlinOBP14 in A. lineolatus using quantitative real-time PCR. The results demonstrate that the method we developed is both feasible and reliable. In addition, this method exhibited good stability and specificity in detection of chemically synthesized targets in vitro as well as the expression of the target OBP gene in vivo.OBPs play a crucial role in the recognition of ligands and are involved in the initial steps of semiochemical perception. The diverse expression of OBP genes allows them to participate in different physiological functions in insects. In contrast to classic OBPs with typical olfactory roles in A. lineolatus, the physiological functions of Plus-C OBPs remain largely unknown. In addition, detection of the expression of insect OBP genes by conventional methods is difficult in vitro. Here, we focused on AlinOBP14, a Plus-C OBP from A. lineolatus, and we developed a PNA-GO-based mRNA biosensor to detect the expression of AlinOBP14. The results demonstrated that AlinOBP14 plays dual roles in A. lineolatus. The AlinOBP14 is expressed beneath the epidermis of the vertex and gena in heads of A. lineolatus, and it functions as a carrier for three terpenoids, while AlinOBP14 is also expressed in the peripheral antennal lobe and functions as a carrier for endogenous compounds such as precursors for juvenile hormone (JH) and JHⅢ. Our investigation provides a new method to detect the expression of OBP genes in insects, and the technique will facilitate the use of these genes as potential targets for novel insect behavioral regulation strategies against the pest.

The evolution of opsin genes\xa0in five species of mirid bugs: duplication\xa0of long-wavelength opsins and loss\xa0of blue-sensitive opsins

BackgroundColor vision and phototactic behavior based on opsins are important for the fitness of insects because of their roles in foraging and mate choice. Related topics, including the duplication and loss of opsin genes, have been well investigated in insect orders such as Coleoptera, Lepidoptera, Hymenoptera, Odonata and Orthoptera, and the findings have been used to develop pest management strategies involving light trapping. Mirid bugs of Hemiptera, which are pests that cause heavy economic losses, show capacity for color discrimination and phototaxis. However, the opsins in mirid bugs remain uncharacterized. Herein, we examined five species to investigate the evolution of opsins in the family Miridae.ResultsUsing RNA-seq, we identified several contigs showing high identity with opsins, including four contigs in Apolygus lucorum and three contigs each in Adelphocoris suturalis, Adelphocoris fasciaticollis, Adelphocoris lineolatus and Nesidiocoris tenuis. Phylogenetic analyses indicated that one of these genes clustered with ultraviolet-sensitive (UV) opsins and that the others clustered with long-wavelength (LW) opsins, suggesting that duplication of LW opsins and loss of blue light-sensitive (B) opsins occurred in mirid bugs. The existence of introns in the LW opsins of mirid bugs suggested that the duplication events were DNA based. Both LW1 and LW2 opsins of mirid bugs were found to be under strong purifying selection. The LW1 opsins were significantly more highly expressed than the LW2 and UV opsins.ConclusionsWe identified the opsins of mirid bugs using five selected mirid species as a representative sample. Phylogenetic analyses clustered one of the genes with UV opsins and the others with LW opsins, suggesting the occurrence of LW opsin duplication and B opsin loss during the evolution of mirid bugs. Intron detection suggested that the identified duplication event was DNA based. The evidence of strong purifying selection and the relatively high expression levels suggested that these opsins exhibit fundamental functions in mirid bugs.

The Adelphocoris lineolatus OBP4: Support for evolutionary and functional divergence of a mirid pheromone-binding protein from that found in lepidopteran moths.

Pheromone-binding proteins (PBPs) have been extensively investigated in lepidopteran moths, but their evolution and function in hemipteran species remain unclear. Our previous study demonstrated that an odorant-binding protein, OBP4, of the mirid bug Adelphocoris lineolatus functions as a candidate hemipteran PBP but clustered with lepidopteran antennae-binding proteins (ABPs) rather than in the PBP/general odorant-binding protein (GOBP) clade. In this study, we hypothesized that origin and function of PBPs in hemipteran bugs may differ from those of lepidopteran moths. To test this hypothesis, we first constructed a phylogenetic tree using insect OBPs from sister hemipteran and holometabolous lineages, and the results indicated that neither OBP4 nor other types of candidate PBPs of mirid bugs clustered with the lepidopteran PBP/GOBP clade. Then, a fluorescence competitive binding assay was employed to determine binding affinities of recombinant OBP4 protein to host plant volatiles, with functional groups different from A. lineolatus sex pheromone components. The results revealed that OBP4 highly bound the female adult attractant 3-hexanone and 15 other mirid bug biologically active plant volatiles. Finally, we examined cellular expression profiles of OBP4 in putative antennal sensilla that are related to female A. lineolatus host plant location. The fluorescence in situ hybridization and immunocytochemical labeling assay showed that the OBP4 gene was highly expressed in the multiporous olfactory sensilla medium-long sensilla basiconica rather than in the short sensilla basiconica or uniporous sensilla chaetica. These results, together with those of our previous studies, indicate that OBP4 not only functions in recognition of bug-produced sex pheromones in males, but is probably involved in detection of host plant volatiles in both A. lineolatus sexes. Our findings support the hypothesis that the origin and function of PBPs in hemipteran bugs differ from those of well-known PBPs in lepidopteran moths, which provides a novel perspective on evolutionary mechanisms of sex pheromone communication across insect orders.

Sex Pheromone of the Alfalfa Plant Bug, Adelphocoris lineolatus: Pheromone Composition and Antagonistic Effect of 1-Hexanol (Hemiptera: Miridae)

The sex pheromone composition of alfalfa plant bugs, Adelphocoris lineolatus (Goeze), from Central Europe was investigated to test the hypothesis that insect species across a wide geographical area can vary in pheromone composition. Potential interactions between the pheromone and a known attractant, (E)-cinnamaldehyde, were also assessed. Coupled gas chromatography-electroantennography (GC-EAG) using male antennae and volatile extracts collected from females, previously shown to attract males in field experiments, revealed the presence of three physiologically active compounds. These were identified by coupled GC/mass spectrometry (GC/MS) and peak enhancement as hexyl butyrate, (E)-2-hexenyl butyrate and (E)-4-oxo-2-hexenal. A ternary blend of these compounds in a 5.4:9.0:1.0 ratio attracted male A. lineolatus in field trials in Hungary. Omission of either (E)-2-hexenyl-butyrate or (E)-4-oxo-2-hexenal from the ternary blend or substitution of (E)-4-oxo-2-hexenal by (E)-2-hexenal resulted in loss of activity. These results indicate that this Central European population is similar in pheromone composition to that previously reported for an East Asian population. Interestingly, another EAG-active compound, 1-hexanol, was also present in female extract. When 1-hexanol was tested in combination with the ternary pheromone blend, male catches were reduced. This compound showed a dose-response effect with small doses showing a strong behavioral effect, suggesting that 1-hexanol may act as a sex pheromone antagonist in A. lineolatus. Furthermore, when (E)-cinnamaldehyde was field tested in combination with the sex pheromone, there was no increase in male catch, but the combination attracted both males and females. Prospects for practical application are discussed.

Host plants transfer induced regulation of the chemosensory genes repertoire in the alfalfa plant bug Adelphocoris lineolatus (Goeze)

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.

Алматы қаласындағы жартылай қаттықанаттылардың (Heteroptera) фаунасы

The article presents the results of research conducted by the authors on the territory of Almaty in 2020-2021. Research works are devoted to the fauna, biology and ecology of hemiptera on the territory of the city. Hemiptera, or bedbugs, are the most numerous group of insects of great practical importance. Hemiptera are widely distributed in the city.When collecting the material, standard entomological methods were used - collecting with an entomological net, catching small insects with an exhauster, at night on an artificial light source, manual collection, etc. As a result of studies of hemiptera in Almaty, 43 species from 4 families were identified. According to the number of species, the family Miridae prevails – 22 species (51%), Anthocoridae – 9 species (21%), and from the family Tingidae, Nabidae – 6 species (14% each). Of these, Stenodema calcarata, Lygus pratensis, Lygus rugulipennis, Adelphocoris lineolatus, Deraeocoris punctulatus, Nabis ferus are mass, 21 are common, 16 are rare. According to their proximity to the habitats, the hemiptera of Almaty are divided into several groups: dendrobionts (10 species), dendro-tamno-hortobionts (2 species), dendro-tamno-hortobionts (1 species), hortobionts (20 species), herpetobionts (1 species), dendro-hortobionts (3 species), tamno-hortobionts (4 species), horto-tamno-dendrobionts (2 species). All 4 known types of voltinism are characteristic of the semiptera of Almaty. According to the number of generations per year, all species of hemiptera of Almaty can be divided into several groups: 1) monovoltine (14 species), 2) bivoltine (15 species), 3) having 2-3 generations per year (10 species), 4) polyvoltine (4 species). The biology and ecology of hemiptera are studied rather unevenly. The hemiptera of Almaty belong to mesophilic species. Hemiptera are insects with incomplete transformation and go through the following stages of development – egg, larva and imago. They are characterized by wintering at different stages of development. In most species of Almaty, the winter diapause occurs at the imago stage (29 species), but few species overwinter in the egg stage (14 species).

Broadly Tuned Odorant Receptor AlinOR59 Involved in Chemoreception of Floral Scent in Adelphocoris 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.

Dynamics of the Composition and Density of Insects on Aboveground Organs of Alfalfa in the Forest-Steppe of Samara Province

This paper presents analysis of the effects of the alfalfa crop age, sowing method, phenological development phases, and green mass mowing on the composition and density of insects and spiders on the aboveground organs of alfalfa grown in crop rotation without irrigation, pest control measures, and fertilizers. The main inhabitants of alfalfa crops comprised over 50 species, with prevalence of the chewing herbivores: alfalfa weevil Hypera postica, alfalfa seed chalcid Bruchophagus roddi, nodule weevils Sitona lineatus and S. inops; the sucking herbivores: flower thrips Odontothrips sp., gorse shield bug Piezodorus lituratus, lucerne bug Adelphocoris lineolatus, plant bug Lygus pratensis, cowpea aphid Aphis craccivora, and pea aphid Acyrthosiphon pisum; the predators: spiders, predatory bug Orius niger, predatory thrips Aeolothrips sp., and variegated ladybug Hippodamia variegata. The seasonal dynamics of the composition and density of dominant groups was more pronounced in the first-year crops than in 2–4 year old ones. In field crop rotations without the use of insecticides, plots with periodic green mass mowing during the budding and flowering phases of alfalfa seed crops should alternate with unmown plots, so that plots with blossoming plants should be present in the field throughout the summer. This measure would promote the development and maintenance of highly diverse insect complexes, attract predators and pollinators, provide additional feeding for parasitic Hymeno­ptera, and reduce the number and harmfulness of herbivores as the result of greater trophic competition between them as well as of the impact of entomophages.

Sensilla localization and sex pheromone recognition of odorant binding protein OBP4 in the mirid plant bug Adelphocoris lineolatus (Goeze)

Pheromone binding proteins (PBPs) are well studied in lepidopteran moths and are considered to be crucial in detection of sex pheromones as well as some green leaf volatiles. In contrast, evidence that PBPs interact with sex pheromones of hemipteran species is not available. The mirid plant bug, Adelphocoris lineolatus (Goeze), is a notorious hemipteran pest that uses two butyrate esters, trans-2-hexenyl butyrate (E2HB) and hexyl butyrate (HB), and one hexenoic aldehyde trans-4-oxo-2-hexenal (E4O2H), as sex pheromones. In the present study, we report on an odorant binding protein, AlinOBP4, with particular focus on its potential physiological roles in the detection of A. lineolatus sex pheromone components. Phylogenetic analyses indicated that AlinOBP4 and two mirid orthologs clustered in a general phylogenetic clade with the lepidopteran ABX OBPs, the fly LUSH and the OBP83a/b subfamily. Cellular localization by fluorescence in situ hybridization and immunolabeling further demonstrated that AlinOBP4 was strongly expressed in the multiporous sensilla trichodea (str) and middle long sensilla basiconica (mlsba) of male A. lineolatus adults, suggesting a key role associated with sex pheromone and odorant detection. A ligand binding assay revealed that recombinant AlinOBP4 protein highly bound not only to the sex pheromone components E4O2H but also to some host plant volatiles. These findings together with the evidence of insect PBPs available in the literature support the view that AlinOBP4 is involved in sex pheromone detection in male A. lineolatus and provide foundational information for further elucidating the molecular mechanisms of chemosensory based mating behavior in hemipteran mirid bugs.

Does Harvesting Affect the Spatio-Temporal Signature of Pests and Natural Enemies in Alfalfa Fields?

Determining the spatio-temporal distribution and association of pests and natural enemies would be useful for implementing biological control of pests and could also be used in site-specific pest management. In this study, the spatio-temporal distribution and association of aphids, plant bugs, and natural enemies were assessed in alfalfa fields using geo-statistics and spatial analysis by distance indices (SADIE). Additionally, the effect of alfalfa hay-harvesting on the spatial and temporal distribution of these insects was investigated for the first time. Geostatistical analysis indicated that the degree of dependence (DD) was ≥75% for 11 out of 39, 9 out of 35, 3 out of 12, 10 out of 29, and 2 out of 20 datasets for pea aphid Acyrthosiphon pisum, spotted alfalfa aphid Therioaphis maculata, cowpea aphid Aphis craccivora, alfalfa plant bug Adelphocoris lineolatus, and tarnished plant bug Lygus rugulipennis, respectively. The results also indicated that DD was ≥75% in 7 out of 45, 18 out of 45, and 3 out of 20 datasets for Coccinella septempunctata, Hippodamia variegata, and Pterostichus melanarius, respectively. Harvesting decreased the aggregation of the ladybirds, which resulted in a decrease in the index of aggregation. The geo-statistics results were confirmed by SADIE in 75% of datasets. These results can be used in biological control and site-specific management of aphids and plant bugs in alfalfa fields.

Expression patterns and ligand binding characterization of Plus-C odorant-binding protein 14 from Adelphocoris lineolatus (Goeze)

Odorant-binding proteins (OBPs) can bind and transport hydrophobic odorants across the sensillum lymph to the olfactory receptors (ORs) and play crucial roles in insect chemosensory systems. Although the ligand spectra of classical OBPs have been extensively characterized, little is known about OBPs in the Plus-C subgroup. Here, we focus on AlinOBP14, a Plus-C OBP from the hemipteran mirid bug pest Adelphocoris lineolatus (Goeze). Quantitative real-time PCR experiments suggest that AlinOBP14 is ubiquitously expressed at different developmental stages but is highly expressed in the adult head, the non-chemosensory organ. Fluorescence-based competitive binding assays show that β-ionone, nerolidol, farnesol and insect juvenile hormone III (JHIII) strongly bind to AlinOBP14. No significant internal binding pocket is predicted by homology modeling. Instead, the long N-terminal and C-terminal regions and parts of several α-helixes form a cupped cavity to accommodate ligands. Molecular docking reveals that the four potential ligands have distinct binding orientations, implying different roles of the N-terminal extension in ligand recognition. This hypothesis is further confirmed via a ligand binding assay in which the recombinant N-terminal mutant AlinOBP14 displays comparable binding affinities for β-ionone and trans, trans-farnesol but decreased binding affinities for nerolidol and JHIII. Thus, our current study is the first to characterize the ligand binding spectra of a Plus-C OBP in hemipteran insect species and reveals that N-terminal extensions could be required for its recognition of putative ligands.

Molecular characterization and expression analysis of putative odorant carrier proteins in Adelphocoris lineolatus

Abstract 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.