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Four-eyed bark beetles of the genus Polygraphus have been involved in large bark beetle outbreaks in different parts of the world, resulting in major economic losses. A striking example is the invasive species Polygraphus proximus which is a pest on Abies sibirica in Russia. In Sweden, Polygraphus poligraphus has been involved in bark beetle outbreaks on Norway spruce, Picea abies, together with the European spruce bark beetle Ips typographus. Two related species, Polygraphus punctifrons and Polygraphus subopacus are also present in Sweden. Recently, aggregation pheromones or pheromone components have been identified for these four Polygraphus species. However, questions remain regarding the complete composition of their pheromones, particularly for P. subopacus and P. proximus, whose aggregation pheromones appear to be very similar. In an attempt to better understand the chemical communication of these species, additional studies were conducted on P. poligraphus, P. punctifrons and P. subopacus using solid phase microextraction coupled with gas chromatography and mass spectrometry (SPME-GC-MS), electroantennography (EAG) as well as SPME-GC-MS and GC-MS with electroantennographic detection (EAD). Field experiments were also conducted. In P. punctifrons, some male-specific compounds were found in addition to those previously identified. In EAG and SPME-GC-MS/EAD studies, all three Polygraphus species responded strongly to grandisol. Using a chiral column, GC-MS/EAD revealed that they were able to detect both enantiomers of grandisol. In summary, this work presents our current understanding of the aggregation pheromones in four Polygraphus species and the challenges we have met in identifying species-specific pheromone blends for some of these species., Competing Interests: Declarations. Competing Interests: The authors declare no competing interests., (© 2025. The Author(s).)

The eastern larch beetle, Dendroctonus simplex LeConte, colonizes tamarack, Larix laricina (Du Roi) K. Koch, and has become a major tree killer in parts of its temperate North American range. To fill existing gaps in knowledge of this insect's pheromone system, we used gas chromatography-mass spectrometry to perform quantitative studies of pheromone production by unfed beetles of both sexes, founding females excised from newly established galleries in a tamarack log, and both sexes excised post-pairing. To identify olfactory stimulants and thereby possible, additional pheromone components, we performed gas chromatography-electroantennographic detection analyses with antennae of both sexes exposed to volatiles collections from the beetles. We also exposed unfed male and female beetles to juvenile hormone III (JH III) to identify pheromone components regulated through this mechanism. Both female and male beetles exhibited antennal responses to 1,5-dimethyl-6,8-dioxabicyclo[3.2.1]octane (frontalin), 3-methylcyclohex-2-en-1-ol (seudenol), and 3-methylcyclohex-2-en-1-one (MCH) in volatiles of solitary mining females. Within approximately 24 h of joining a male, female production of seudenol and MCH largely ceased while production of frontalin continued. Unfed females produced no more than minute amounts of pheromone, and application of JH III induced production of frontalin from some females but not seudenol or MCH. Unfed males and males exposed to JH III produced almost no volatiles, whereas paired males produced minute amounts of frontalin (possibly an artifact), no seudenol or MCH, and some oxygenated monoterpenes. We found that timing of production of certain pheromone components was inconsistent with their known activity., Competing Interests: Declarations. Competing Interests: The authors declare no competing interests., (© 2025. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

The present study aims to investigate the differences between cork oak acorns from natural and semi-natural stands in terms of morphology, insect attack rate, and acorn chemical composition. Moreover, it examines the metabolic responses induced by insect attacks. The results show that acorns from the semi-natural stand in our study are larger than those from the natural stand. In addition, the insect attack rate was higher in the natural stand (8.25%) than in the semi-natural stand (6.25%). Furthermore, acorns in the semi-natural stand exhibit high total flavonoid content (TFC), whereas those in the natural stand are rich in total phenolic content (TPC). In terms of biochemical changes in acorns, the study revealed a remarkably significant difference in TPC, TFC, and antioxidant activity subsequent to infestation by Cydia and Curculio insects. Cydia -infested acorns from the natural stand had higher TPC levels, with a value of 93.96±0.39 mg GAE/g, showing a 17.7% increase over healthy acorns. Acorns from the semi-natural stand attacked by Curculio show the highest TFC with a value of 0.288±0.004 mg EQ/g, showing a 121.5% increase over healthy acorns. Moreover, both DPPH and FRAP methods revealed that antioxidant activity of the acorns from the semi-natural stand attacked by Curculio was more effective. This research is crucial for providing a solid foundation for the selection of highquality cork oak germplasm resources and exploring the potential valorization of insect-affected acorns in the realms of food and agriculture.

The red palm weevil Rhynchophorus ferrugineus (Coleoptera: Curculionidae) is one of the most harmful pests for palm trees, causing serious economic damage worldwide. The present work aims to model and study the 3D structures of highly expressed odorant binding proteins from R. ferrugineus (RferOBPs) and identify possible binding modes and ligand release mechanism by docking and molecular dynamics. Highly confident 3D structures of a total of 11 odorant binding proteins (OBPs) were obtained with AlphaFold2. All 3D RferOBPs modeled structures displayed six characteristic α-helices, except for RfeOBP7 and RfeOBP10, which had an extra terminal α-helix. Among the eleven modeled RferOBPs, RferOBP4 was highly expressed in the antennae and subsequently selected for further analyses. Molecular docking analyses demonstrated that ferruginol, α-pinene, DEET, and picaridin can favorably bind the RferOBP4 cavity with low affinity energies. Molecular dynamic simulations of RferOBP4 bound to ferruginol at different pH values showed that low pH environments dictate a structural change into an apo-state that modifies the number of tunnels where the ligand can coexist, further triggering ligand release by a pH-dependent mechanism. This is the first report concerning the modelling and study of ligand binding modes and release mechanism of R. ferrugineus OBPs.Communicated by Ramaswamy H. Sarma.

Of recent, immense attention has been given to chitosan in the biomedical field due to its valuable biochemical and physiological properties. Traditionally, the chief source of chitosan is chitin from crab and shrimp shells. Chitin is also an important component of fish scales, insects and fungal cell walls. Thus, the aim of this study was to isolate and characterize chitosan from locally available material for potential use in the biomedical field. Chitosan ash and nitrogen contents ranged from 1.55 to 3.5% and 6.6 to 7.0% respectively. Molecular weight varied from 291 to 348KDa. FTIR spectra revealed high degree of similarity between locally isolated chitosan and commercial chitosan with DD ranging from 77.8 to 79.1%. XRD patterns exhibited peaks at 2θ values of 19.5° for both mushroom and banana weevil chitosan while Nile perch scales chitosan registered 3 peaks at 2θ angles of 12.3°, 20.1° and 21.3° comparable to the established commercial chitosan XRD pattern. Locally isolated chitosan exhibited antimicrobial activity at a very high concentration. Ash content, moisture content, DD, FTIR spectra and XRD patterns revealed that chitosan isolated from locally available materials has physiochemical properties comparable to conventional chitosan and therefore it can be used in the biomedical field.

Background: Bark beetles are major pests of conifer forests, and their behavior is primarily mediated via olfaction. Targeting the odorant receptors (ORs) may thus provide avenues towards improved pest control. Such an approach requires information on the function of ORs and their interactions with ligands, which is also essential for understanding the functional evolution of these receptors. Hence, we aimed to identify a high-quality complement of ORs from the destructive spruce bark beetle Ips typographus (Coleoptera, Curculionidae, Scolytinae) and analyze their antennal expression and phylogenetic relationships with ORs from other beetles. Using 68 biologically relevant test compounds, we next aimed to functionally characterize ecologically important ORs, using two systems for heterologous expression. Our final aim was to gain insight into the ligand-OR interaction of the functionally characterized ORs, using a combination of computational and experimental methods., Results: We annotated 73 ORs from an antennal transcriptome of I. typographus and report the functional characterization of two ORs (ItypOR46 and ItypOR49), which are responsive to single enantiomers of the common bark beetle pheromone compounds ipsenol and ipsdienol, respectively. Their responses and antennal expression correlate with the specificities, localizations, and/or abundances of olfactory sensory neurons detecting these enantiomers. We use homology modeling and molecular docking to predict their binding sites. Our models reveal a likely binding cleft lined with residues that previously have been shown to affect the responses of insect ORs. Within this cleft, the active ligands are predicted to specifically interact with residues Tyr84 and Thr205 in ItypOR46. The suggested importance of these residues in the activation by ipsenol is experimentally supported through site-directed mutagenesis and functional testing, and hydrogen bonding appears key in pheromone binding., Conclusions: The emerging insight into ligand binding in the two characterized ItypORs has a general importance for our understanding of the molecular and functional evolution of the insect OR gene family. Due to the ecological importance of the characterized receptors and widespread use of ipsenol and ipsdienol in bark beetle chemical communication, these ORs should be evaluated for their potential use in pest control and biosensors to detect bark beetle infestations.

Conotrachelus dimidiatus (Coleoptera: Curculionidae) interacts with immature guava fruits (Psidium guajava L.) for feed, sleep, mate and oviposit. Determination of the volatile organic compounds (VOCs) emitted by the insect and immature fruits can help improve understanding of plant-insect and intraspecific insect interactions between females and males of C. dimidiatus. Daytime fruit setting emissions of immature guava consist mainly of limonene, caryophyllene, and aromadendrene. In addition to the host's volatiles, the aim of this study was to assess the VOCs released by the insect. Static headspace-solid phase microextraction (SHS-SPME), combined with gas chromatography/quadrupole time of flight mass spectrometry (GC/Q-ToF-MS), allowed the identification of the C 10 terpenoids: grandlure I, II, II, IV, grandisoic acid, papayanol and papayanal bioactive compounds released by female and male C. dimidiatus under laboratory conditions. These chemical compounds are candidates for the preparation of a lure formulation., (© 2020 Wiley-VHCA AG, Zurich, Switzerland.)

Insect cuticle lipids are involved in various types of chemical communication between species, and reduce the penetration of insecticides, chemicals, and toxins, as well as provide protection against the attack of microorganisms, parasitic insects, and predators. Ecological studies related to the insect Rhynchophorus palmarum are well-known; however, very little is known about its resistance mechanisms, which includes its lipid composition and its importance, specifically the cuticle layer. This study aimed to characterize the cuticle and internal lipid compounds of the male and female R. palmarum adult insects and to evaluate the presence of antimicrobial activity. We performed by gas chromatography coupled to mass spectrometry (GC-MS) analyzes of lipid extracts fractions and we identified 10 methyl esters of fatty acids esters of C14 to C23, with variation between the sexes of C22:0, C21:0, present only in male cuticle, and C20:2 in female. The lipid content of this insect showed relevant amount of C16:1, C18:1, and C18:2. The antimicrobial activity of the cuticular and internal fractions obtained was tested, which resulted in minimum inhibitory concentrations between 12.5 and 20 μg/ml against Gram-positive bacteria (Staphylococcus epidermidis, Enterococcus faecalis), Gram-negative (Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia), and fungal species (Candida albicans e Candida tropicalis). The antimicrobial effect of the R. palmarum cuticle open perspectives for a new source to bioinsecticidal strategies, in addition to elucidating a bioactive mixture against bacteria and fungi., (© 2020 Wiley Periodicals LLC.)

Prior research from trapping experiments using synthetic pheromone components suggested the existence of local and geographical variation in the pheromone system of the spruce beetle, Dendroctonus rufipennis (Kirby). To test hypotheses concerning variation in the spruce beetle's aggregation pheromone blend, we extracted volatiles from the hindguts of individual spruce beetles sampled from sites in eastern Canada (Nova Scotia and Newfoundland) and western Canada (British Columbia and Alberta) and quantified the amounts of four known aggregation pheromone components within each sample. Chiral analyses were performed on a subset of samples. Frontalin (1,5-dimethyl-6,8-dioxabicyclo[3.2.1]octane) was more dominant in western Canada, whereas MCOL (1-methyl-2-cyclohexen-1-ol) and seudenol (3-methyl-2-cyclohexen-1-ol) were more dominant in the east. Verbenene (4-methylene-6,6-dimethylbicyclo[3.1.1]hept-2-ene) was prevalent only in one of our six sites (Rocky Mountain House, AB). Female beetles in Rocky Mountain House (AB) also produced a higher proportion of (+)-frontalin than females from the other sites, and a comparison to previously published data suggests additional geographic variation that was not captured among our sites. When paired with a male in a gallery, female spruce beetles produced pheromone blends with more frontalin and less MCOL compared to solitary female beetles. Our results show that variation in the spruce beetle's pheromone blend exists at both large and small spatial scales, possibly a consequence of local selective pressures and assortative mating.

The fig tree weevil Aclees sp. cf. foveatus (Coleoptera: Curculionidae), introduced in Italy in 2005, is currently causing significant economic and environmental losses to fig tree nurseries and orchards in Central Italy. Fig damages are due to the adults feeding on leaves and fruits, and to the galleries dug by the xylophagous larvae in the trunk, which lead the plants to death. To date, no chemical or biological control methods resulted to be effective against this invasive pest. In order to gain information about possible semiochemicals involved in mate recognition and choice, both the volatile organic compounds (VOCs) and the epicuticular lipids of male and female specimens were analysed. VOCs emissions of specimens were characterized essentially by monoterpenes, while epicuticular lipids contained long chained 2-ketones, alkanes, alkenes, including some methyl alkenes, and several fatty acid propyl esters. The attractiveness of reconstituted VOCs blends of the two sexes was tested in electrophysiological and behavioural assays in laboratory conditions. Both the male and the female reconstituted VOCs drove a significant response towards individuals of the opposite sex, thus demonstrating features of sexual attractants. Our results suggest a possible application of VOCs blends as pheromonic attractants in field monitoring and mass trapping of Aclees sp. cf. foveatus.

This work aimed to evaluate the inhibition of Candida rugosa lipase by five guanylhydrazone derivatives through biological, biophysical and theoretical studies simulating physiologic conditions. The compound LQM11 (IC 50  = 14.70 μM) presented the highest inhibition against the enzyme. Therefore, for a better understanding of the interaction process, spectroscopic and theoretical studies were performed. Fluorescence and UV-vis assays indicate a static quenching mechanism with non-fluorescent supramolecular complex formation and changing the native protein structure. The binding process was spontaneous (ΔG < 0) and electrostatic forces (ΔH < 0 and ΔS > 0) played a preferential role in stabilizing the complex ligand-lipase. The compounds were classified as non-competitive inhibitors using orlistat as a reference in competition studies. Based on the 1 H NMR assays it was possible to propose the sites of ligand (epitope) that bind preferentially to the enzyme and the theoretical studies were consistent with the experimental results. Finally, LQM11 was efficient as a lipase inhibitor of the crude intestinal extract of larvae of Rhynchophorus palmarum, an important agricultural plague, showing potential for control of this pest. Within this context, the real potential of this biotechnological application deserves further studies., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Insect-derived volatiles seem to provide reliable chemical cues that plants could employ to defend themselves. Here we investigated the effect of pheromone emission from a closely associated (Anthonomus grandis; boll weevil) and an unassociated (Tibraca limbativentris) herbivore on cotton volatile emission. Exposure to A. grandis aggregation pheromone induced cotton defence response by enhancing the emission of volatiles attractive to the natural enemy of A. grandis, the parasitic wasp Bracon vulgaris, but only when the pheromonal blend was complete (all four components). Individual components of A. grandis aggregation pheromone were not able to induce cotton plants to increase the release of volatiles. On the other hand, T. limbativentris sex pheromone did not induce any change in the cotton constitutive volatile profile. Our results support the hypothesis that plants are able to detect pheromones of tightly co-evolved herbivores. Moreover, A. grandis pheromone exposure induced similar volatile compounds to herbivore-induced cotton, such as linalool, (E)-ocimene, (E)-4,8-dimethylnona-1,3,7-triene (DMNT), and (E,E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene (TMTT). We also showed that the larval ectoparasitoid B. vulgaris relies on boll weevil's aggregation pheromone and pheromone-induced plant volatiles as kairomones to locate suitable hosts., (© The Author(s) 2019. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

The bearded weevil, Rhinostomus barbirostris (Coleoptera: Curculionidae: Dryophthorinae), attacks coconut trees, oil palms and other species of Arecaceae. Besides direct damage, R. barbirostris may be a vector of diseases in coconut and oil palms, such as stem bleeding (resinosis) and red ring disease. Currently, the only method to control this weevil is by visual observation of damage and removal of infected plants. Semiochemical-based trapping could improve the effectiveness of monitoring and management of R. barbirostris. In comparisons of volatiles released by R. barbirostris males and females by gas chromatography (GC) two male-specific compounds were observed. GC-mass spectrometry (MS) and GC-Fourier transform-infrared (FTIR) analyses of the natural compounds suggested these were diastereoisomers of 5-hydroxy-4-methylheptan-3-one, also known as sitophilure, a pheromone component of other dryophthorine species. Synthesis of the mixture of all four stereoisomers of sitophilure was performed in two steps, and the chemical structures were confirmed by comparing GC retention times and MS and FTIR spectra of natural and synthetic compounds. The absolute configurations of the two male-specific compounds were elucidated by enantioselective GC; the major component was the (4S,5R)-isomer, and the minor component (4S,5S)-sitophilure. In analyses by GC-electroantennography (EAG) the antennae of male and female R. barbirostris only responded to the (4S,5R)-isomer of the synthetic sitophilure. The stereoisomeric mixture of sitophilure was attractive to both sexes of R. barbirostris in laboratory experiments in the presence of sugar cane volatiles, and a similar result was obtained in a preliminary field trapping test.

Constitutive expression of Odorant-Binding Proteins (OBPs) in antennae and other body parts has been examined mainly to infer their involvement in insect olfaction, while their regulation in response to semiochemical stimuli has remained poorly known. Previous studies of semiochemical response were basically done using electrophysiology, which integrates the response of the set of OBPs present in an antenna or sensillum, without revealing the regulation of OBPs or which ones might be involved. In this study we used boll weevil as a model and mined its OBPs by RNA-Seq to study their simultaneous antennal expression by qPCR under controlled semiochemical stimuli with aggregation pheromone and plant volatiles. In the absence of a semiochemical stimulus, 23 of 24 OBPs were constitutively expressed in the antenna in both sexes. Semiochemicals changed systemically the expression of OBPs in both sexes. There were different patterns of up- and down-regulation in female antennae for each semiochemical stimulus, consistent with female chemical ecology. On the other hand, the only response in males was down-regulation of some OBPs. We suggest that these systemic changes in OBP expression might be related to enhancing detection of the semiochemical stimuli and/or priming the olfactory system to detect other environmental chemicals.

The coffee bean weevil (CBW), Araecerus fasciculatus (De Geer, 1775), is a cosmopolitan stored-product pest, especially in tropical and subtropical areas. Previous reports showed evidence for aggregation behavior of CBW and this study aimed to identify and evaluate the aggregation pheromone of this pest. Whole-body solvent extractions were analyzed by coupled gas chromatography-mass spectrometry and comparison of male and female extracts showed a male-specific compound which was identified as squalene, 2,6,10,15,19,23-hexamethyl-2,6,10,14,18,22-tetracosahexaene. This compound was shown to attract male and female CBW in Y-tube olfactometer and storage trap assays. The longevity of septum lures was also evaluated in a warehouse. Squalene could be useful in monitoring and controlling this pest.

We investigated the chemical composition of the weevil Rhynchophorus ferrugineus larvae, traditionally used as human food in Asia and known worldwide as one of the most significant pest for palm trees. Total fat content and fatty acid composition were analyzed using standard methodologies in (1) weevil larvae reared on apple fruit slices and wild specimens collected from attacked (2) Phoenix canariensis and (3) Syagrus romanzoffiana palm trees. Total fat content was extremely high in all the specimens (ranged between 57.62 and 60.03% based on dry weight). Despite sharing the same prevalent fatty acids (myristic acid, palmitic acid, stearic acid, palmitoleic acid, oleic acid, α-linoleic acid, and α-linolenic acid), fatty acid composition of the wild weevil larvae significantly differed from that of the specimens raised on apple fruit, due to the presence of other minor compounds. In general, a good balance between unsaturated fatty acids (∼53.68% of total fatty acids) and saturated fatty acids (∼43.41% of total fatty acids) and a low cholesterol content (74.61-152.32 mg/kg based on dry matter) were detected in all the specimens. Conversely, the weevil larvae did not represent a good source of α-tocopherol (14.17-26.22 mg/kg based on dry matter). The ability of the protein extracts obtained from the weevil larvae to inhibit in vitro the angiotensin-converting enzyme, the main enzyme involved in blood pressure regulation, was also investigated. To simulate gastrointestinal digestion process, protein extracts were hydrolyzed by the gastrointestinal enzymes. A significantly lower IC 50 (0.588-0.623 mg/ml) was measured in all the protein extracts after enzymatic hydrolysis versus the corresponding crude protein extracts (3.270-3.752 mg/ml). Given that the weevil larvae are able to provide interesting benefits for human health, this study supports their use as human food not just in the native countries where they are traditionally consumed and farmed but also throughout the world.

The polyphagous shot hole borer (PSHB), Euwallacea sp., was first detected in 2003 in Los Angeles County, California, USA. Recently, this invasive species has become a major pest of many hardwood trees in urban and wildland forests throughout southern California. PSHB is nearly identical in morphology and life history to the tea shot hole borer (TSHB), Euwallacea fornicatus, an invasive pest of hardwoods in Florida, USA and many other parts of the world. However, molecular studies have suggested that the taxa are different species. We conducted morphometric and chemical analyses of the phenotypes of Euwallacea sp. collected in southern California (Los Angeles County) and E. fornicatus collected in Florida (Miami-Dade County). Our analyses indicated that PSHB has 3 larval instars. The third larval instar was separated from the first 2 instars by head capsule width with 0 probability of misclassification. The body length, head width, and pronotal width of PSHB adult males were significantly less than those of females. Head width and pronotal width of female PSHB were significantly less than those of female TSHB. In contrast, body length, and ratio of body length to pronotal width of female PSHB were significantly greater than those of female TSHB. However, females of these 2 species could not be separated completely by these 4 measurements because of the overlapping ranges. Cuticular hydrocarbons detected in both species were exclusively alkanes (i.e., n-alkanes, monomethylalkanes, dimethylalkanes, and trimethylalkanes). Cuticular hydrocarbon profiles of PSHB males and females were similar, but they both differed from that of TSHB females. Cuticular hydrocarbons of PSHB were predominantly internally branched dimethylalkanes with backbones of 31 and 33 carbons, whereas cuticular hydrocarbons of TSHB females were dominated by internally branched monomethylalkanes and dimethylalkanes with backbones of 28 and 29 carbons. Multiple compounds within these classes appear to be diagnostic for PSHB and TSHB, respectively., (© 2016 Institute of Zoology, Chinese Academy of Sciences.)

Insect cuticular hydrocarbons (CHCs) play important roles in chemical communication, as well as having ecological and physiological roles. The use of CHCs for mate recognition has been shown in many insect genera, but little is known about their use in the tea weevil Myllocerinus aurolineatus. Here, we provide evidence that CHCs on the surface of sexually mature M. aurolineatus females act as contact sex pheromones, facilitating mate recognition and eliciting copulatory behavior in male weevils. Using gas chromatography-mass spectrometry, we identify n-pentacosane and n-heptacosane as two potential contact pheromone components. Results from arena bioassays showed that n-pentacosane is a component of a contact pheromone of M. aurolineatus. Further results from the Y-tube olfactometer bioassays showed that n-pentacosane also acts as a volatile attractant. Our results greatly improve our understanding of the chemical ecology of M. aurolineatus.

The four-spotted coconut weevil, Diocalandra frumenti Fabricius (Coleoptera: Dryophthoridae), is a small weevil found attacking economically important palm species, such as coconut, date, oil, and Canary palms. Given the scarcity of detection and management tools for this pest, the availability of a pheromone to be included in trapping protocols would be a crucial advantage. Previous laboratory experiments showed evidence for aggregation behavior; thus, our main goal was to identify the aggregation pheromone in this species. The volatile profile of D. frumenti individuals was studied by aeration and collection of effluvia in Porapak-Q and also by solid phase microextraction (SPME) techniques. Moreover, solvent extraction of previously frozen crushed individuals was also performed. All resulting extracts and SPME fibers were analyzed by gas chromatography coupled to mass spectrometry (GC-MS). The comparison of male and female samples provided the candidate compound, 5-ethyl-2,4-dimethyl-6,8-dioxabicyclo[3.2.1]octane (multistriatin), whose biological activity was evaluated in olfactometer and field assays.

The invasive red palm weevil, Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae), is considered one of the world's most devastating insect pests to palm trees. It was observed that larvae of this pest are able to inhibit microbial growth on the rearing media when they start feeding and this observation has led us to study the effect of red palm weevils on various microbial species. The antimicrobial effect of extracts from different parts of the alimentary canal on Gram positive bacteria ( Enterococcus faecalis and Staphylococcus aureus ), Gram negative bacteria ( Escherichia coli and Klebsiella spp.), Candida albicans, and Penicillium sp. was tested using the agar well diffusion method. All extracts inhibited the tested microbial species. Foregut extracts had the greatest zones of growth inhibition. Enterococcus faecalis , Staphylococcus aureus, and Penicillium sp. were significantly sensitive to the extracts and had the largest growth inhibition zones. It is concluded that the gut extracts contain potent antimicrobial activity and may provide a new source of antimicrobial peptides.

The sugarcane stem weevil, Acrotomopus atropunctellus (Boheman) (Curculionidae: Molytinae: Cholini) is an important economic pest from the Northwestern region of Argentina. Analyses of the headspace volatiles produced by separated males and females revealed one male-specific compound. Its structural identification is reported here in using gas chromatography coupled with mass spectroscopy analysis and chemical micro-reactions. Besides, two laboratory olfactometry assays allowed us to propose 6-methyl-5-hepten-2-one (sulcatone) as an aggregation pheromone for this insect, being attractive to both conspecific males and females. This compound is reported for the first time as involved in the Curculionidae family communication.

Eastern Palearctic conifers are subject to frequent bark beetle outbreaks. However, neither the species responsible nor the semiochemicals guiding these attacks are well understood. Two high-mountain Ips species on Qinghai spruce, Picea crassifolia, I. shangrila and I. nitidus, are typical in this regard. Six synthetic candidate pheromone components that we earlier identified from hindguts of unmated males of these two Ips species were tested for field activity in Qinghai province, P. R. China. For I. nitidus, racemic ipsdienol ((±)-Id) could replace the naturally-produced blend of enantiomers containing 74% (-)-(S)-Id (74:26 S:R), in attractive ternary or binary blends. In contrast, sympatric I. shangrila were attracted mainly to blends including Id of opposite chirality, 97%-(+)-(R)-Id. Of the verbenols, (-)-trans-verbenol was inactive for I. nitidus or inhibitory for I. shangrila, but (-)-cis-verbenol (cV) was a key component of the pheromone in both species. Two fully factorial experiments demonstrated that (±)-Id, cV, and 2-methyl-3-buten-2-ol (MB) are components of the aggregation pheromone of I. nitidus, whereas only (+)-Id and cV are essential components of the aggregation pheromone of I. shangrila. While MB is not necessary for attraction of I. shangrila, it is an active antagonist and likely functions in species isolation. A review of the pheromone production and responses in Palearctic Ips and Pseudoips showed that cV is more common than methylbutenols, and both elicit qualitatively variable responses. Ipsdienol is the most common component with variable chirality, and is a necessary, but often not sufficient, factor for determining pheromone specificity.

Despite the importance of data reduction as part of the processing of reflection-based classifications, this study represents one of the first in which the effects of both spatial and spectral data reductions on classification accuracies are quantified. Furthermore, the effects of approaches to data reduction were quantified for two separate classification methods, linear discriminant analysis (LDA) and support vector machine (SVM). As the model dataset, reflection data were acquired using a hyperspectral camera in 230 spectral channels from 401 to 879 nm (spectral resolution of 2.1 nm) from field pea (Pisum sativum) samples with and without internal pea weevil (Bruchus pisorum) infestation. We deployed five levels of spatial data reduction (binning) and eight levels of spectral data reduction (40 datasets). Forward stepwise LDA was used to select and include only spectral channels contributing the most to the separation of pixels from non-infested and infested field peas. Classification accuracies obtained with LDA and SVM were based on the classification of independent validation datasets. Overall, SVMs had significantly higher classification accuracies than LDAs (P < 0.01). There was a negative association between pixel resolution and classification accuracy, while spectral binning equivalent to up to 98% data reduction had negligible effect on classification accuracies. This study supports the potential use of reflection-based technologies in the quality control of food products with internal defects, and it highlights that spatial and spectral data reductions can (1) improve classification accuracies, (2) vastly decrease computer constraints, and (3) reduce analytical concerns associated with classifications of large and high-dimensional datasets.

Using samples from eastern China (c. 25 - 41° N and 99 - 123° E) and from a common garden experiment, we investigate how Mg concentration varies with climate across multiple trophic levels. In soils, plant tissue (Oriental oak leaves and acorns), and a specialist acorn predator (the weevil Curculio davidi), Mg concentration increased significantly with different slopes from south to north, and generally decreased with both mean annual temperature (MAT) and precipitation (MAP). In addition, soil, leaf, acorn and weevil Mg showed different strengths of association and sensitivity with climatic factors, suggesting that distinct mechanisms may drive patterns of Mg variation at different trophic levels. Our findings provide a first step toward determining whether anticipated changes in temperature and precipitation due to climate change will have important consequences for the bioavailability and distribution of Mg in food chain.

Attributing a season and a date to the volcanic eruption of Santorini in the Aegean has become possible by using preserved remains of the bean weevil, Bruchus rufipes, pests of pulses, from the storage jars of the West House, in the Bronze Age settlement at Akrotiri. We have applied an improved pre-treatment methodology for dating the charred insects, and this provides a date of 1744-1538 BC. This date is within the range of others obtained from pulses from the same context and confirms the utility of chitin as a dating material. Based on the nature of the insect material and the life cycle of the species involved, we argue for a summer eruption, which took place after harvest, shortly after this material was transported into the West House storeroom.

Bark beetles (Curculionidae: Scolytinae) are major cause of woody plants death in the world. They colonize the stem and other parts of trees recognizing host-produced specific compounds (kairomones) and insect pheromones. Bark beetle's antennae and alimentary canal participate in the host selection identifying chemical compounds produced by trees and insects, and also in the metabolism and detoxification of these compounds. The red turpentine beetle (RTB), Dendroctonus valens LeConte, is an unaggressive species that colonize > 40 pine species (Pinaceae) in North and Central America. Several studies suggest that bark beetle cytochrome P450 enzymes are involved in monoterpene oxidation. In this study we identified by means of PCR, cloning, sequencing, and bioinformatic analysis, eleven full-length genes: five CYP4, four CYP6, and two CYP9 in the antennae and gut region of RTB, after stimulation with vapors of monoterpenes: (±)-α-pinene, (R)-(+)-α-pinene, (S)-(-)-β-pinene, (S)-(-)-α-pinene and (+)-3-carene; pine trees volatiles used by RTB as kairomones. The recovered cDNA of these genes vary from 1.5 kb to 1.8 kb and the open frame encodes from 496 to 562 amino acid proteins. The bioinformatic analysis suggests that the majority of P450 proteins encoded by these genes are membrane anchored in the endoplasmic reticulum. RT-qPCR assays showed differential expression of all CYP genes between male and female. The gene expression was dependent of monoterpenes and exposure time, with some of them sex, antennae and gut region specific. Significant differences among monoterpenes, gut region, antennae and exposure time were found. Our results suggest that some of these genes may be involved in the detoxification process of these compounds during tree colonization., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

An investigation to identify a sex or aggregation pheromone of Sitona discoideus Gyllenhål (Coleoptera: Curculionidae) is presented. Antenna flicking and attraction behaviors evoked by conspecifics of both sexes were recorded in arena bioassays, where attraction of females to males was observed. Air entrainment of both males and females was conducted in separate chambers. Gas chromatographic-mass spectrometric analysis of headspace volatiles revealed that two male-specific compounds, 4-methyl-3,5-heptanedione (major) and (4S,5S)-5-hydroxy-4-methyl-3-heptanone (minor), were emitted during the autumnal post-aestivatory flight period. The stereoisomers of the minor component were separated by enantioselective gas chromatography and their absolute configurations assigned by NMR (diastereomers) and the known preference of enantioselective transesterification reactions catalyzed by Candida antarctica lipase B. Electroantennogram and single sensillum recording studies indicate that 4-methyl-3,5-heptanedione as well as all individual stereoisomers of 5-hydroxy-4-methyl-3-heptanone are detected by the antennae of male and female S. discoideus. Further, single sensillum recordings suggest that both sexes of S. discoideus have specialized olfactory receptor neurons (ORNs) for detecting 4-methyl-3,5-heptanedione and different populations of stereoselective ORNs for detecting the stereoisomers of 5-hydroxy-4-methyl-3-heptanone. Some of these stereoselective ORNs appear to be sex-specific in S. discoideus.

The coffee berry borer (CBB; Hypothenemus hampei) is a major pest of coffee responsible for significant crop losses worldwide. The entomopathogenic fungus Beauveria bassiana represents a natural means of controlling this insect pest; however, little is known concerning the molecular determinants that contribute to the virulence of the fungus towards the CBB. In order to examine genes involved in insect virulence, two expressed sequence tag (EST) libraries, representing germinating conidia and growing hyphae/mycelia of B. bassiana cells grown on cuticular extracts of the CBB were constructed and analysed. In total, 4186 cDNA transcripts were obtained, which included 2141 from the cuticle-germinated conidia and 2045 from the cuticle-grown mycelium libraries, respectively. The average sequence length obtained was 470 bp and transcript assembly resulted in a set of 1271 and 1305 unique gene sequences for the conidial and mycelia libraries, respectively. Around 50 % of the sequences in each library could be annotated by gene ontology terms. An analysis of the two generated libraries as well as a previously reported EST library of B. bassiana grown on chitin was performed. Between the cuticle-germinated conidia and the cuticle-grown mycelia libraries, 322 unique gene sequences were shared, of which 90 % could be annotated, leaving 949 unique cuticle-germinated conidial genes and 983 unique growing hyphae/mycelia genes of which around 65 % were annotated. ESTs shared between the libraries indicated a basic response pattern for B. bassiana against H. hampei, which included genes implicated in pathogenicity. The expression profiles of four genes were evaluated with a cyclophilin, an alkaline-like serine protease and a mitogen-activated protein kinase (MAPK), showing elevated expression during initial phases of infection, i.e. conidia germinating on insect extracts. These data provide clues and gene candidates for further exploration concerning the biology and molecular mechanisms of entomopathogenicity by this fungus.

Analyses of the headspace volatiles produced by males and females of Sternechus subsignatus Boheman (Coleoptera: Curculionidae) revealed seven male-specific compounds. The major component was (E)-2-(3,3-dimethylcyclohexylidene)-ethanol, and the minor components were 1-(2'-hydroxyethyl)-1-methyl-2-isopropenylcyclobutane (grandisol), 7-methyl-3-methyleneoct-6-en-1-ol, (Z)-2-(3,3-dimethylcyclohexylidene)-ethanol, (Z)- and (E)-2-(3,3-dimethylcyclohexylidene)-acetaldehyde, and (E)-2-(3,3-dimethylcyclohexylidene) acetic acid. The latter compound is described for the first time as a natural product. Only four of the seven identified compounds showed electrophysiological activity. Enantioselective gas chromatography showed that the natural grandisol is the (1R,2S)-stereoisomer. The major component, (E)-2-(3,3-dimethylcyclohexylidene)-ethanol, attracted S. subsignatus in olfactometer bioassays. Studies are in progress to evaluate the biological activity of the major component and the EAD-active mixture under field conditions.

Many herbivores are sensitive to the secondary chemistry of their host plants. However, the influence of pine secondary chemicals (monoterpenes) on bark beetle fitness is poorly understood. We tested the hypothesis that the monoterpene composition of the phloem oleoresin of ponderosa pine, Pinus ponderosa var scopulorum, mediates rates of host acceptance, oviposition behavior, and fecundity of the western pine beetle, Dendroctonus brevicomis. We performed reciprocal rearing experiments, controlling for the monoterpene composition (chemotype) of host material. We tested the effects of two geographically interspersed host chemotypes on beetles with unknown (wild) and known (reared F(1)) chemical histories. Host chemotype and insect chemical history did not affect rates of acceptance of host material by female beetles. Insect chemical history affected egg gallery construction, and beetles constructed egg galleries that were on average 24.3% longer when reared in host material that was chemically similar to their natal host material. However, mean egg gallery lengths did not differ between host chemotypes. Insect chemical history also influenced fecundity: F(1) beetles produced 52.7% more offspring on average when reared in host material that was chemically similar to their natal host. Our experiments demonstrate that the chemical history of bark beetles mediates egg gallery construction and fecundity, but not host acceptance. This implicates chemical history as a more important factor than host chemotype in the oviposition behavior and fecundity of D. brevicomis.

Sugarcane is an important crop that has recently become subject to attacks from the weevil Sphenophorus levis, which is not efficiently controlled with chemical insecticides. This demands the development of new control devices for which digestive physiology data are needed. In the present study, ion-exchange chromatography of S. levis whole midgut homogenates, together with enzyme assays with natural and synthetic substrates and specific inhibitors, demonstrated that a cysteine proteinase is a major proteinase, trypsin is a minor one and chymotrypsin is probably negligible. Amylase, maltase and the cysteine proteinase occur in the gut contents and decrease throughout the midgut; trypsin is constant in the entire midgut, whereas a membrane-bound aminopeptidase predominates in the posterior midgut. The cysteine proteinase was purified to homogeneity through ion-exchange chromatography. The purified enzyme had a mass of 37 kDa and was able to hydrolyze Z-Phe-Arg-MCA and Z-Leu-Arg-MCA with k(cat)/K(m) values of 20.0±1.1 μM(-1)s(-1) and 30.0±0.5 μM(-1)s(-1), respectively, but not Z-Arg-Arg-MCA. The combined results suggest that protein digestion starts in the anterior midgut under the action of a cathepsin L-like proteinase and ends on the surface of posterior midgut cells. All starch digestion takes place in anterior midgut. These data will be instrumental to developing S. levis-resistant sugarcane., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

The chemical properties of the African palm weevil, Rhychophorus phoenicis (F.) (Coleoptera: Curculionidae), larvae were evaluated using standard methodology. The chloroform-methanol extract yielded 37.12% on a dry basis. The oil was liquid at room temperature with a flash point of 36.0 °C. Analysis of the physical constants indicated values of 192.25 Wijs and 427.70 mg KOH/g as iodine and saponification, respectively. Fatty acid analysis of the extracted oil showed the presence of unsaturated fatty acids at low levels. Palmitic acid and stearic acid constituted 35.3 and 60.5% of the oil, respectively. The usual behaviour of the oil at room temperature, irrespective of the level of unsaturation of its constituent fatty acid was noted. The total protein content of the defatted palm weevil larva (dry basis) was estimated at 66.3%. The amino acid values compared favourably to FAO reference protein, except for tryptophan, which was limiting. All the other essential amino acids were adequate. Mineral analysis revealed high levels of potassium (1025 mg/100 g) and phosphorus (685 mg/100 g). The dried and defatted palm weevil lava represents a very good source of protein, and a good complement of essential amino acids.

Cephalonomia stephanoderis and Prorops nasuta are two bethylid wasps released into several Latin American countries for classical biological control of coffee berry borer, Hypothenemus hampei, the most serious insect pest of coffee worldwide. Recent studies on the host location behaviour of these parasitoids have shown that females of both species are attracted to volatile compounds released by immature stages and dust and frass of H. hampei. In this study, we investigated the role of the contact chemicals present in dust and frass of H. hampei on the behaviour of P. nasuta and C. stephanoderis females. Parasitoids remained longer on patches treated with methanol extracts than on acetone and hexane extracts. Females spent more time on the patch treated with the methanol extract of dust and frass than on the patches treated with the methanol extract of dry coffee and methanol control. The concentration of the methanol extracts from dust and frass influenced the locomotory activity of parasitoids of both species. The time that females spent in the patch tended to increase as the concentration of the methanol extracts increased. A further experiment aimed to identify other behavioural descriptors and gain a deeper understanding of the mechanisms underlying the response of parasitoids to methanol extracts was performed. Females of both species spent more time, covered more distance, turned more (per unit time and per unit distance), and decreased their speed when they contacted patches treated with methanol extracts in comparison to patches treated with methanol control.

The raspberry weevil, Aegorhinus superciliosus (Guérin) (Coleoptera: Curculionidae), is the most important pest in blueberry and raspberry fields in the south of Chile. In this study, we investigated the electroantennographic and behavioral responses of A. superciliosus to semiochemicals released from conspecific individual adults, with particular attention to male attraction to females. Odors released from females significantly attracted males in a Y-tube olfactometer. Gas chromatographic and mass spectral analysis of female volatile extracts revealed the presence of limonene and α-pinene. Electroantennogram recordings from both sexes indicated that males of A. superciliosus possess olfactory sensitivity for the R isomer of limonene and α-pinene, whereas females only perceived R-limonene. Behavioral assays using synthetic compounds showed that only R-limonene elicited an attraction response from male weevils. Field experiments confirmed the laboratory results, showing that R-limonene was attractive to weevils. This is the first report of intraspecific chemical communication in this weevil. We discuss the origin of these compounds, their possible role in the sexual behavior of this species, and their potential use in a pest control strategy.

The polyphagous insect Sitophilus oryzae L. (Coleoptera:Curculionidae) has a tremendous adaptability in feeding behaviour, making it a serious invasive pest of stored cereals. The present study identifies the metabolite composition of Sitophilus oryzae (S. oryzae) using Nuclear Magnetic Resonance (NMR) spectroscopy. Assignment of 1D-proton by NMR, 1H-1H COSY, 2D-TOCSY 1H-1H, had been done. Amongst the various biochemically important metabolites isoleucine, valine, leucine, beta-hydroxybutyrate, lysine, glutamate, glutamine, proline, lactate, alanine, di-methylamine, alpha-glucose, beta-glucose, choline, glycerophosphorylcholine and tyrosine are present in S. oryzae. In wheat-fed S. oryzae, the presence of threonine and the absence of lactate is observed. In rice-fed S. oryzae, however, the presence of lactate and the absence of threonine were observed. Barley-fed S. oryzae shows presence of both tyrosine and lactate. It is concluded that the pest S. oryzae has adaptability on different stored cereals and grains, depicting the presence of earlier reported metabolites. The present study aims to identify the key metabolic components and associated enzymes in Sitophilus oryzae fed on different cereals.

A couple of different members of the coleopteran genus Otiorhynchus (Coleoptera: Curculionidae) are becoming increasingly important as pests of nursery and ornamental plants in global horticulture. Although adult weevils are morphologically distinguishable by skilled personnel, high potential for misidentification is given for cryptic larval stages. For developing and applying efficient pest management strategies the determination of the respective species is however a prerequisite, because each species may have a different phenology or a varying susceptibility to pesticides. Here, we report on the development of a diagnostic polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method for differentiation among 16 Otiorhynchus and seven other weevil species independent of their developmental stage. An approximately 780-bp fragment of the mitochondrial cytochrome oxidase subunit II was amplified and subsequently digested with at most four restriction enzymes generating species-specific fragment patterns. The assay was validated on a total of 127 individuals and the obtained fragment patterns correctly identified 23 different weevil species. The PCR-RFLP method reported here is cost-effective, robust, and fast and could be used in the future by plant protection services for diagnostic purposes.

Scyphophorus acupuncatus Gyllenhal is considered to be the most significant pest of cultivated agaves in the world. Recent studies on the chemical ecology of this weevil have shown that males release a pheromone that attracts both sexes. In this study, we investigated the effect of feeding, aging, photoperiod, and time of day on pheromone release by S. acupuncatus males under laboratory conditions. The pheromone released by individual males was sampled using solid-phase microextraction and analyzed by gas chromatography-coupled mass spectrometry. Our results show that food is an important factor because weevils deprived of plant material did not release any pheromone. In addition, we found that males fed with apple, a nonhost plant, released less pheromone than weevils fed with agave. Host odor does not seem to be important in stimulating pheromone release. We found that males as young as 1 mo were able to release pheromone, although the numbers of individuals releasing pheromone increased with age. Older males released more pheromone than younger males. We found that S. acupuncatus males released pheromone during the photophase and scotophase; there was, however, no significant peak in pheromone release. Also, the pheromone released by S. acupunctatus was not affected by the length of the photoperiod.

We examined the genetic structure of populations of an ambrosia beetle, Xylosandrus brevis (Eichhoff) (Curculionidae: Scolytinae), to understand its colonization dynamics. We collected specimens from 20 sites in Japan and studied the genetic structure of these populations using portions of the mitochondrial cytochrome oxidase I gene (COI). A phylogenetic analysis showed three distinct lineages (clades A, B, and C) within X. brevis. Clade A had 65 haplotypes from all the populations, except for populations from Nagano (Chiisagata-gun) and the Ryukyu Islands (Ishigaki), whereas clade B had 14 haplotypes from nine populations (Yamagata, Saitama, Shimo-Minochi-gun, Chiisagata-gun, Toyota, Watarai-gun, Wakayama, Tottori, and Kochi), and clade C had 6 haplotypes from the Ryukyu Islands (Ishigaki) population (and nowhere else). Nested clade phylogeographic analysis showed 65 clade A haplotypes and 14 clade B haplotypes geographically structured in two clades, respectively. A contact zone was identified in the Chubu and Tokai areas. Our results suggest that gene flow and individual movement of X. brevis between the Ryukyu Islands and the other three main islands of Japan has been rare, and X. brevis may be divided into two populations, eastern-central and northern-western, with little gene flow between the four areas of western Japan (Kinki, Chugoku, Shikoku, and Kyushu).

Molting in insects is regulated by ecdysteroids and juvenile hormones. Several synthetic non-steroidal ecdysone agonists are on the market as insecticides. These ecdysone agonists are dibenzoylhydrazine (DBH) analogue compounds that manifest their toxicity via interaction with the ecdysone receptor (EcR). Of the four commercial available ecdysone agonists, three (tebufenozide, methoxyfenozide and chromafenozide) are highly lepidopteran specific, one (halofenozide) is used to control coleopteran and lepidopteran insects in turf and ornamentals. However, compared to the very high binding affinity of these DBH analogues to lepidopteran EcRs, halofenozide has a low binding affinity for coleopteran EcRs. For the discovery of ecdysone agonists that target non-lepidopteran insect groups, efficient screening systems that are based on the activation of the EcR are needed. We report here the development and evaluation of two coleopteran-specific reporter-based screening systems to discover and evaluate ecdysone agonists. The screening systems are based on the cell lines BRL-AG-3A and BRL-AG-3C that are derived from the weevil Anthonomus grandis, which can be efficiently transduced with an EcR reporter cassette for evaluation of induction of reporter activity by ecdysone agonists. We also cloned the almost full length coding sequence of EcR expressed in the cell line BRL-AG-3C and used it to make an initial in silico 3D-model of its ligand-binding pocket docked with ponasterone A and tebufenozide.

Volatiles from hindgut extracts of males of the Qinghai spruce bark beetle, Ips nitidus, from different attack phases (phase 1: unpaired males and phases 2-4: males joined with one to three females) and hindgut extracts of mated females were analyzed by gas chromatography-mass spectrometry (GC-MS)/flame ionization detection (FID) with both polar and enantioselective columns. The GC-MS/FID analyses demonstrated that unpaired males from attack phase 1 (nuptial chamber constructed) produced 2-methyl-3-buten-2-ol, approx. 74%-(-)-ipsdienol, and (-)-cis-verbenol as major hindgut components, and (-)-trans-verbenol, (-)-ipsenol, (-)-verbenone, myrtenol, and 2-phenylethanol as minor or trace components. The quantities of 2-methyl-3-buten-2-ol and especially ipsdienol decreased after mating during phases 2-4, whereas the quantities of (-)-cis- and (-)-trans-verbenol did not change. In contrast, the quantity of (-)-ipsenol seemed to increase as mating activity progressed. After mating with three females (harem size = 3; phase 4), only trace to small amounts of male-specific compounds were detected from I. nitidus male hindguts. Chemical analysis of the hindgut extracts of mated females showed only trace amounts of semiochemicals. A field-trapping bioassay in Qinghai, China showed that the four-component "full blend" containing the three major components, 2-methyl-3-buten-2-ol, (+/-)-ipsdienol, and (-)-cis-verbenol, plus a minor component, (-)-trans-verbenol, caught significantly more I. nitidus (male/female = 1:2.2) than did the unbaited control and two binary blends. The replacement of (+/-)-ipsdienol with nearly enantiomerically pure (-)-ipsdienol in the "full blend" significantly reduced trap catches, which suggests that both enantiomers are needed for attraction. On the other hand, removal of (-)-trans-verbenol from the active "full blend" had no significant effect on trap catches. Our results suggest that the three major components, 2-methyl-3-buten-2-ol, 74%-(-)-ipsdienol, and (-)-cis-verbenol (at 7:2:1), produced by unpaired fed males, are likely the aggregation pheromone components of I. nitidus, thus representing the first characterization of an aggregation pheromone system of a bark beetle native solely to China.

The grain weevil, an insect (pest) that infects grain, is a frequent contaminant of processed wheat, and its presence may contribute to respiratory abnormalities in grain workers. We studied the in vitro effects of an extract of grain weevil (GWE) on airway smooth muscle. Pharmacologic studies included in vitro challenge of guinea pig trachea with GWE, in parallel organ baths, pretreated with mediator-modifying agents or a control solution. Dose-related contractions of nonsensitized guinea pig trachea (GPT) were demonstrated using this extract. Pharmacologic studies were performed by pretreating guinea pig tracheal tissue with drugs known to modulate smooth muscle contraction: atropine, indomethacin, pyrilamine, acivicin, NDGA, BPB, TMB8, captopril, and capsaicin. Atropine, pyrilamine, BPB, and capsaicin significantly reduced the contractile effects of the extract at most of the challenge doses (p < 0.01 or p < 0.05). Inhibition of GWE-induced contraction by blocking of other mediators was less complete. We suggest that GWE causes dose-related airway smooth muscle constriction of the GPT by nonimmunologic mechanisms involving a variety of airway mediators and possibly cholinergic receptors.

Diaprepes abbreviatus (L.) (Coleoptera: Curculionidae) is a root weevil introduced into the United States from the Caribbean in 1964. It is associated with >300 plants, including citrus, sugarcane, and potatoes. D. abbreviatus is widespread in Florida, and it has recently been detected in limited areas of California and Texas. The purpose of this research is to evaluate the utility of 16S ribosomal (16S rRNA) and cytochrome oxidase I (COI) mitochondrial markers for the delineation of genetic populations of D. abbreviatus in Florida and for the characterization of patterns of dispersion among these populations. We also assessed these markers as genetic tools for the clarification of taxonomic uncertainties in specimens from Dominica (Lesser Antilles). We analyzed 111 weevils from six Florida populations and six specimens from Dominica. In Florida, we found three haplotypes with only one haplotype in each population. Florida haplotypes differed by one to three nucleotide substitutions, possibly the result of a recent divergence from one source population or three different introductions from closely related populations from the Caribbean. In contrast, specimens from Dominica showed a high genetic variability with three 16S haplotypes and six unique COI haplotypes, delineating two mitochondrial clades. We show that these mitochondrial markers are useful for phylogeographic studies of D. abbreviatus.

Subtle differences in pheromone components of sympatric species should be attractive only to the producing species and unattractive or repellent to the nonproducing species, and thereby maintain reproductive isolation and reduce competition between species. Bark beetles Dendroctonus brevicomis and D. frontalis (Coleoptera: Curculionidae) are known to have common pheromone components, except for exo-brevicomin, which is produced by D. brevicomis. We predicted that D. frontalis would not respond to exo-brevicomin outside of the zone of sympatry with D. brevicomis. We conducted a field experiment to determine the effect of exo-brevicomin on attraction of D. frontalis and associated species in Mississippi. We determined whether D. frontalis pheromone production differed inside and outside the sympatric zone and compared the pheromone profiles with D. brevicomis within the sympatric zone. Trapping studies revealed that D. frontalis can perceive and respond positively to exo-brevicomin, an aggregation pheromone of a sympatric congener (D. brevicomis), at locations hundreds of kilometers outside the sympatric zone. Qualitative pheromone profiles showed that both species emit similar pheromone components: frontalin, endo-brevicomin, exo-brevicomin, trans-verbenol, verbenone, and myrtenol. Although not previously reported, D. frontalis males from Arizona produced exo-brevicomin. The predator Thanasimus dubius did not discriminate traps baited with exo-brevicomin and was most attracted to traps with frontalin. Hylastes beetles were significantly attracted to traps baited with exo-brevicomin in combination with other compounds. Our results raise new practical and evolutionary questions on the role of exo-brevicomin in the behavioral ecology of D. frontalis. The addition of exo-brevicomin to the current lure might increase the efficiency of trapping programs in the southeastern United States.

Lipid transport in arthropods is achieved by highly specialized lipoproteins, which resemble those described in vertebrate blood. Here we describe purification and characterization of the lipid-apolipoprotein complex, lipophorin (Lp), from adults and larvae of the cowpea weevil Callosobruchus maculatus. We also describe the Lp-mediated lipid transfer to developing oocytes. Lps were isolated from homogenates of C. maculatus larvae and adults by potassio bromide gradient and characterized with respect to physicochemical properties and lipid content. The weevil Lp (465 kDa) and larval Lp (585 kDa), with hydrated densities of 1.22 and 1.14 g/mL, contained 34 and 56% lipids and 9 and 7% carbohydrates, respectively. In both Lps, mannose was the predominant monosaccharide detected by paper chromatography. SDS-PAGE revealed two apolipoproteins in each Lp with molecular masses of 225 kDa (apolipoprotein-I) and 79 kDa (apolipoprotein-II). The lipids were extracted and analyzed by thin-layer chromatography. The major phospholipids found were phosphatidylserine, phosphatidylcholine and phosphatidylethanolamine in adult Lp, and phosphatidylcholine, phosphatidylethanolamine and sphingomyelin in larval Lp. Hydrocarbons, fatty acids and triacylglycerol were the major neutral lipids found in both Lps. Lps labeled in the protein moiety with radioactive iodine (125I-iodine) or in the lipid moiety with fluorescent lipids revealed direct evidence of endocytic uptake of Lps in live oocytes of C. maculatus.

Heterotrophic organisms must obtain essential elements in sufficient quantities from their food. Because plants naturally exhibit extensive variation in their elemental content, it is important to quantify the within-species stoichiometric variation of consumers. If extensive stoichiometric variation exists, it may help explain consumer variation in life-history strategy and fitness. To date, however, research on stoichiometric variation has focused on interspecific differences and assumed minimal intraspecific differences. Here this assumption is tested. Natural variation is quantified in body stoichiometry of two terrestrial insects: the generalist field cricket, Gryllus texensis Cade and Otte (Orthoptera: Gryllidae) and a specialist curculionid weevil, Sabinia setosa (Le Conte) (Coleoptera: Curculionidae). Both species exhibited extensive intraspecific stoichiometric variation. Cricket body nitrogen content ranged from 8-12% and there was a four-fold difference in body phosphorus content, ranging from 0.32-1.27%. Body size explained half this stoichiometric variation, with larger individuals containing less nitrogen and phosphorus. Weevils exhibited an almost three-fold difference in body phosphorus content, ranging from 0.38-0.97%. Overall, the variation observed within each of these species is comparable to the variation previously observed across almost all terrestrial insect species.

Extrusion is used to produce crunchy expanded foods, such as snacks. The nutritional impact of this process has not been studied sufficiently. In this study, in vitro and in vivo protein and starch bioavailability was evaluated in both raw and extruded corn (Zea mays)(C) and lima bean (Phaseolus lunatus)(B) flour blends, prepared in 75C/25B and 50C/ 50B (p/p) proportions. These were processed with a Brabender extruder at 160 degrees C, 100 rpm and 15.5% moisture content. Proximate composition showed that in the extruded products protein and ash contents increased whereas the fat level decreased. In vitro protein digestibility was higher in the extrudates (82%) than in the raw flours (77%). Potentially available starch and resistant starch contents decreased with extrusion. The in vitro assays indicated that extrusion improved protein and starch availability in the studied blends. In vivo bioavailability was evaluated using the rice weevil (Sithophilus oryzae) as a biological model. The most descriptive biomarkers of the changes suggested by the in vivo tests were body protein content (increased by extrusion) and intestinal a-amylase activity (decreased by processing). Overall, results suggest that extrusion notably increases the nutritional quality of corn and lima bean flour blends.

Male Metamasius spinolae (Gylh.) produce several volatile compounds that are likely constituents of its aggregation pheromone. These compounds were identified by volatile collections and gas chromatography (GC), followed by coupled gas chromatography-mass spectrometry (GC-MS), as 2-methyl-4-heptanone [1], 6-methyl-2hepten-4-one [2], and 2-hydroxy-2-methyl-4-heptanone [3]. Preliminary field experiments using synthetic racemates of these compounds showed that significantly more adult cactus weevils were caught in traps baited with the major single compound three or the 2 + 3 binary combination than in unbaited control traps. However, highest trap efficacy occurred with the 1 + 2 binary combination and a blend of all three synthetic compounds plus prickly pear. Potential uses for the cactus weevil pheromone and possible ways to increase trap captures are discussed.

Eupelmus vuilleti (Hymenoptera; Eupelmidae) is a host feeding ectoparasitoid of fourth-instar larvae or pupae of Callosobruchus maculatus (Coleoptera; Bruchidae) infecting Vigna unguiculata seed and pods (Fabacae). Parasitoid females are synovigenic, i.e. they are born with immature eggs and need to feed from the host in order to sustain egg production. In this study, the role of sterols obtained through host feeding in parasitoid oogenesis are examined. Quantitative and qualitative analyses of the sterol contents in each partner of the tritrophic interaction show that a parasitoid female's larval sterol contents is sufficient to produce only 30% of the total number of eggs laid throughout a female's life cycle. In a second step, by manipulating the composition of the sterols hemolymph in the host, it is shown that cholesterol obtained through adult nutrition plays a crucial role in the eggs viability but does not affect the egg production quantitatively. This result has important implications for understanding both the nutrient allocation strategy in this species and the impact of cholesterol in parasitoid reproduction.