<Emphasis Type="Italic">Vitex agnus-castus</Emphasis> is a Preferred Host Plant for <Emphasis Type="Italic">Hyalesthes obsoletus</Emphasis>

Hyalesthes obsoletus Signoret (Homoptera: Cixiidae) is a polyphagous planthopper that transmits stolbur phytoplasma (a causative agent of yellows disease) to various weeds, members of the Solanaceae, and wine grapes (Vitis vinifera L.) in Europe and the Middle East. Planthoppers were collected by hand vacuuming eight native plant species. Vitex agnus-castus L., a shrub in the Verbenaceae, hosted the largest number of H. obsoletus, although Olea europaea L. also served as a host for adults. Using a Y-olfactometer, we compared the planthoppers relative preference for V. agnus-castus, Convolvulus arvensis, and V. vinifera. V. agnus-castus was more attractive to both male and female H. obsoletus than the other plants. H. obsoletus antennal response was stronger to volatiles collected from V. agnus-castus than from Cabernet Sauvignon variety of V. vinifera. To determine if V. agnus-castus would serve as a reservoir for the pathogen, H. obsoletus were collected from leaf and stem samples of native V. agnus-castus, and were tested by polymerase chain reaction (PCR) for the presence of phytoplasma DNA. While 14% and 25% (2003 and 2004, respectively) of the insects tested positive for phytoplasma DNA, none of the plant samples tested positive. To determine if V. agnus-castus could serve as a host plant for the development of the planthopper, we placed emergence cages beneath field shrubs and enclosed wild-caught H. obsoletus in a cage with a potted young shrub. We found adult H. obsoletus in the emergence cases and planthopper nymphs in the soil of the potted plant. We concluded that V. agnus-castus is attractive to H. obsoletus, which seems to be refractory to phytoplasma infections and warrants further testing as a trap plant near vineyards.     

20-Hydroxyecdysone Deters Oviposition and Larval Feeding in the European Grapevine Moth, Lobesia botrana

European grapevine moth females (Lobesia botrana, Lepidoptera Tortricidae) select an oviposition site by tasting the host plant surface and then gluing a single egg on berries from grapes or from several other host plant species. In doing so, females should avoid ovipositing on plants that are detrimental to their progeny. Do they sense the same deterrent compounds as larvae, despite the fact that they do not have access to the same compartments of the plants? We tested this hypothesis with 20-hydroxyecdysone (20E), purified from Leuzea carthamoides. Phytoecdysteroids are usually found inside plant tissues and accessible to larvae in an aqueous phase, while adults would access them only through the epicuticular wax. We first confirmed that larvae avoid feeding on 20E and that they taste 20E with their lateral sensilla styloconica, at a threshold of 10^?6 M. Then, we tested whether adult females avoid ovipositing on glass spheres sprayed with 20E. When given a choice, females avoided laying eggs on a treated surface, at a threshold of 8 ng/cm². In addition, they deposited significantly fewer eggs in the presence of 20E. Presuming that legs play an important role in assessing the oviposition substrate, we assessed the sensitivity of their taste receptors. In females, 14 taste sensilla are located on the ventral side of the last tarsus of the prothoracic leg. One group of these sensilla house one neuron that is sensitive to 20E, with a detection threshold of about 10^?7 M. The same molecule is thus sensed both in larvae and adults of L. botrana where it respectively inhibits feeding and oviposition.     

Innate Responses to Putative Ancestral Hosts: Is the Attraction of Western Flower Thrips to Pine Pollen a Result of Relict Olfactory Receptors?

Pollinophagy is widely documented in the order Thysanoptera, with representative individuals from six of the nine divergent families known to feed on pollen. Various pollens of the genus Pinus increase the development time, fecundity, longevity, and settling preference of Western Flower Thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). Certain species of flower thrips discriminate among pollen types, but no studies have elucidated the olfactory cues that play a role in their pollen preferences. In this study, the volatile organic compounds emitted by pollens of the genus Pinus were elucidated. Various chemicals from pollen headspace elicited electrophysiological responses from WFT antennae. The compound (S)-(-)-verbenone, identified in pollen headspace, attracted WFT in a 4-arm olfactometer. This compound has potential for use in integrated pest management programs against the pest. We present the hypothesis that this polyphagous insect may have retained ancestral ‘relict’ olfactory receptors through the course of evolution, to explain this attraction to pine pollen. This attraction has allowed the insect to find and exploit an unusual nutrient source that significantly increases its fitness. The study demonstrates how fossil record analysis and subsequent evolutionary knowledge can aid in explaining possibilities as to why some insects sense and respond to chemicals that would otherwise seem peculiar to their ecology, allowing insight into the evolutionary forces that may shape insect olfactory systems over time.     

Perception of Oviposition-Deterring Pheromone by Cabbage Seed Weevil (Ceutorhynchus assimilis)

Following oviposition into a pod of oilseed rape (Brassica napus), the female cabbage seed weevil (Ceutorhynchus assimilis) marks the pod with oviposition-deterring pheromone (ODP) by brushing it with her eighth abdominal tergite. On an unmarked pod, oviposition site selection was always accompanied by intensive antennation of the pod. Females approaching a freshly ODP-marked pod brought their antennae within 1 mm of the pod but usually did not antennate it before rejecting it for oviposition. Females with the clubs of their antennae amputated continued to discriminate pods from stems or petioles as oviposition sites but showed no behavioral response to ODP. Extracts of volatiles air-entrained from ovipositing weevils failed to inhibit oviposition. Air passed over a behaviorally active extract of ODP did not elicit a detectable electroantennogram response. By contrast, when presented as a gustatory stimulus to the sensilla chaetica of the antennal club, a behaviorally active extract of ODP from postdiapause, gravid females elicited a strong electrophysiological response. This response usually involved more than one cell and displayed a phasic–tonic time course over the recording period of 10 sec. Extract from prediapause (and hence sexually immature) females elicited neither behavioral nor electrophysiological (contact) responses. Thus the ODP of the cabbage seed weevil is sensed primarily by contact chemoreception at the sensilla chaetica of the antennae, and the electrophysiological responses recorded from these gustatory sensilla are of value as the basis of a bioassay to assist identification of the active constituent(s) of the pheromone.     

A chiral sex pheromone system in the pea midge, Contarinia pisi

The sex pheromone of the pea midge consists of 2-acetoxytridecane, (2S,11S)-diacetoxytridecane and (2S,12S)-diacetoxytridecane. The responses of male pea midges to the corresponding stereoisomers of (2S,11S)-diacetoxytridecane and (2S,12S)-diacetoxytridecane were tested in field trapping experiments and by electroantennographic recordings. When added at 20% of the pheromone component to the sex pheromone blend, the (2S,11R)- and (2R,11S)-stereoisomers of (2S,11S)-diacetoxytridecane, were shown to have a strong inhibitory effect on male attraction in the field. At the same dose, (2R,11R)-diacetoxytridecane, (2R,12R)-diacetoxytridecane, and meso-2,12-diacetoxytridecane, did not have a significant effect on male behavior. It was also shown that substitution of either (2S,11S)-diacetoxytridecane or (2S,12S)-diacetoxytridecane with the related stereoisomers reduced trap catches to the level of blank traps. The electroantennographic recordings showed similar dose–response curves for the pheromone components and the stereoisomers shown to have an inhibitory effect. It seems likely that male antennae have receptors for both pheromone components and for inhibitory stereoisomers. Scanning electron microscopy and transmission electron microscopy of the antennae revealed three types of sensilla involved in chemoreception: sensilla circumfila, sensilla trichodea, and sensilla coeloconica. The sensilla circumfila and trichodea are both innervated by two sensory cells, whereas the sensilla coeloconica are innervated by four to five cells.     

The Preferential Binding of a Sensory Organ Specific Odorant Binding Protein of the Alfalfa Plant Bug Adelphocoris lineolatus AlinOBP10 to Biologically Active Host Plant Volatiles

Semiochemicals such as sex pheromones and plant volatiles are crucial components of insect mating systems and host plant localization. In the olfactory signal transduction pathway, odorant-binding proteins (OBPs) are important elements that function in the first step of the pathway by carrying hydrophobic semiochemicals across the sensillum lymph to the olfactory receptors (ORs). In this study, we examined the binding affinities of semiochemicals to AlinOBP10, a putative OBP from the alfalfa plant bug, Adelphocoris lineolatus, that we demonstrate is expressed mainly in sensory organs. We then characterized the biological activities of the high affinity semiochemicals by measuring their electrophysiological activities in antennae and behavioral responses in the plant bug. AlinOBP10 displayed weak binding affinities to two major putative pheromone components, hexyl butyrate and (E)-2-hexenyl butyrate. In contrast, AlinOBP10 exhibited higher binding affinities to six host plant volatiles, namely myrcene, β-pinene, β-ionone, 3-hexanone, (E)-2-hexenal, and 1-hexanol. The biological activities of these six putative ligands were further studied in electroantennogram recordings and Y-tube olfactometer trials. The three compounds, (E)-2-hexenal, 1-hexanol, and 3-hexanone elicited strong electrophysiological responses, but elicited distinct behaviors. While 3-hexanone was attractive to female adults, (E)-2-hexenal and 1-hexanol were significant repellents. Although a weak electrophysiological response was elicited with β-pinene, it was a strong repellent. These results demonstrate that AlinOBP10 can interact with attractants, as well as repellents, with some specificity toward plant volatiles over sex pheromones.     

Antennal Olfactory Physiology and Behavior of Males of the Ponerine Ant <Emphasis Type="Italic">Harpegnathos saltator</Emphasis>

In comparison to the large amount of study on the communication abilities of females in ant societies and their associated chemical ecology and sensory physiology, such study of male ants has been largely ignored; accordingly, little is known about their olfactory sensory capabilities. To address this, we explored peripheral odor sensitivities in male Harpegnathos saltator by measuring the electrophysiological activity of olfactory sensory neurons within antennal trichoid and coeloconic sensilla using an extracellular recording technique. In an initial trial of 46 compounds, sensilla trichodea responded strongly to two alarm pheromone components, while a limited number of non-hydrocarbon odorants elicited strong responses in sensilla coeloconica. Both sensillar types responded indifferently to 31 cuticular hydrocarbons (CHCs) and synthetic long-chain hydrocarbons (HCs) typically found on insect cuticle. In a search for sensilla responding to CHCs and other compounds, we found some sensilla that responded to synthetic HCs and CHCs from virgin queen postpharyngeal glands that are potentially used in close range mate recognition. Olfactometer bioassays of male ants to 15 non-HCs correlated sensory responsiveness to the respective behavioral responses. Comparing olfactory responses between H. saltator males and females, we found that sensilla coeloconica and basiconica of workers showed greater responses and broader selectivity to all compounds. The rarity of CHC-responding trichoid sensilla in Harpegnathos males suggests a more specific role in sexual communication compared to that in females, which use CHCs in a broader communication context.     

Antennal Olfactory Sensilla Responses to Insect Chemical Repellents in the Common Bed Bug,Cimex lectularius

Populations of the common bed bug Cimex lectularius (Hemiptera; Cimicidae), a temporary ectoparasite on both humans and animals, have surged in many developed countries. Similar to other haematophagous arthropods, C. lectularius relies on its olfactory system to detect semiochemicals in the environment, including both attractants and repellents. To elucidate the olfactory responses of the common bed bug to commonly used insect chemical repellents, particularly haematophagous repellents, we investigated the neuronal responses of individual olfactory sensilla in C. lectularius’ antennae to 52 insect chemical repellents, both synthetic and botanic. Different types of sensilla displayed highly distinctive response profiles. While C sensilla did not respond to any of the insect chemical repellents, Dγ sensilla proved to be the most sensitive in response to terpene-derived insect chemical repellents. Different chemical repellents elicited neuronal responses with differing temporal characteristics, and the responses of the olfactory sensilla to the insect chemical repellents were dose-dependent, with an olfactory response to the terpene-derived chemical repellent, but not to the non-terpene-derived chemical repellents. Overall, this study furnishes a comprehensive map of the olfactory response of bed bugs to commonly used insect chemical repellents, providing useful information for those developing new agents (attractants or repellents) for bed bug control.     

A Female-Biased Odorant Receptor from Apolygus lucorum (Meyer-Dür) Tuned to Some Plant Odors

Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae) is a serious pest of cotton, jujube, grape and many other crops around the world. Understanding how olfactory information directs this insect to its host plants may provide environment-friendly approaches to the control of its population in agriculture. In our study, we cloned an odorant receptor gene, AlucOR46, that was specifically expressed in antennae and female-biased. Functional expression of AlucOR46 in Xenopus oocytes showed that it is tuned to six plant volatiles (S)-(−)-Limonene, (R)-(+)-Limonene, (E)-2-Hexenal, (E)-3-Hexenol, 1-Heptanol and (1R)-(−)-Myrtenol. Electroantennogram (EAG) recordings revealed that all six compounds could elicit electrophysiological responses from the antennae of A. lucorum, higher in females. Our results are in agreement with previous reports showing that (E)-2-Hexenal could attract female A. lucorum in behavior experiments. These results suggest that AlucOR46 might play an important role in locating the host plants of A. lucorum and therefore represents a suitable target for green pest control.     

A field study of chemotactic responses of the marine mud snail,Nassarius obsoletus

Chemotactic responses of the salt marsh mud snailNassarius obsoktus were tested in the field, to the introduction of a crushed conspecific and to the sympatric gastropodLittorina littorea and the bivalveModiolus demissus. The snails responded with burial and escape to the conspecific stimulus, with strong attraction and feeding toM. demissus, and with attraction and feeding toL. littorea. In blank tests, the numbers of snails fluctuated only slightly during half-hour observation periods. An alarm substance appears to be liberated from woundedN. obsoletus which causes rapid disappearance of conspecific snails in an area of up to 50 cm radius.     

Identification of the Aggregation-sex Pheromone of the Cerambycid Beetle <Emphasis Type="Italic">Phymatodes pusillus</Emphasis> ssp. <Emphasis Type="Italic">pusillus</Emphasis> and Evidence of a Synergistic Effect from a Heterospecific Pheromone Component

The longhorn beetle Phymatodes (Poecilium) pusillus ssp. pusillus is a rare, elusive species that is included on Red Lists of threatened species. Previously, 1-hexanol and 1-butanol were reported as putative components of the aggregation-sex pheromone of this species, but behavioral assays to confirm this have not been performed. In this study, we undertook a comprehensive examination of P. p. pusillus to verify the presence of a pheromone. Adult beetles were reared from colonized wood and used for headspace sampling. Analyses by gas chromatography-mass spectrometry revealed that two compounds were present in large quantities in the extracts of males, but absent in extracts from females. Male and female antennae showed repeatable responses to the two compounds in electrophysiological recordings. Using synthetic standards, we were able to identify the compounds as 1-hexanol and 2-methyl-1-butanol. A field bioassay demonstrated that the two compounds were unattractive when applied singly, but elicited significant attraction of female and male beetles when applied in blends of different ratios. We also found that the species exhibited significant attraction to a blend of 3-hydroxy-2-hexanone and 2-methyl-1-butanol, which is the aggregation-sex pheromone of at least two closely related and sympatric species. The presence of the heterospecific component 3-hydroxy-2-hexanone synergized a response to 2-methyl-1-butanol. The pheromone of these species may function as a host cue for P. p. pusillus as the three species have similar phenology and substrate demands. The aggregation-sex pheromone of P. p. pusillus can be used for population monitoring and as a tool to study the general ecology and conservation requirements of this rare species.     

The effect of extraction techniques on yield,extraction kinetics,and antioxidant activity of aqueous-methanolic extracts from nettle (Urtica dioica L.) leaves

Five extraction techniques, maceration, reflux, Soxhlet, Tillepape, and ultrasonic extraction, were used to obtain the extractive matter from nettle leaves. The antioxidant activity of extracts was assessed by DPPH, FRAP, and H₂O₂ test, while the total phenolic and total flavonoid content was determined according to the Folin–Ciocalteu and aluminium chloride methods, respectively. Model Ponomarev and a non-stationary diffusion model through the plant material were used for modelling extraction process. The extract obtained by Soxhlet extraction, containing higher amounts of extractive matter as well as phenolic and flavonoid compounds, showed better antioxidant activity than those obtained by other extraction techniques.     

<Emphasis Type="Italic">cis</Emphasis>-Jasmone Elicits Aphid-Induced Stress Signalling in Potatoes

Elicitation of plant defense signaling that results in altered emission of volatile organic compounds (VOCs) offers opportunities for protecting plants against arthropod pests. In this study, we treated potato, Solanum tuberosum L., with the plant defense elicitor cis-jasmone (CJ), which induces the emission of defense VOCs and thus affects the behavior of herbivores. Using chemical analysis, electrophysiological and behavioral assays with the potato-feeding aphid Macrosiphum euphorbiae, we showed that CJ treatment substantially increased the emission of defense VOCs from potatoes compared to no treatment. Coupled GC-electroantennogram (GC-EAG) recordings from the antennae of M. euphorbiae showed robust responses to 14 compounds present in induced VOCs, suggesting their behavioral role in potato/aphid interactions. Plants treated with CJ and then challenged with M. euphorbiae were most repellent to alate M. euphorbiae. Principal component analysis (PCA) of VOC collections suggested that (E)-2-hexenal, (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene (TMTT), (E)-β-farnesene, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), methyl salicylate (MeSA), CJ, and methyl benzoate (MeBA) were the main VOCs contributing to aphid behavioral responses, and that production of TMTT, (E)-β-farnesene, CJ, and DMNT correlated most strongly with aphid repellency. Our findings confirm that CJ can enhance potato defense against aphids by inducing production of VOCs involved in aphid-induced signalling.     

Olefinic acetates, Δ-9,11–14: OAc and Δ-7,9–12: OAc used as sex pheromone components in three geometrid moths,Idaea aversata,I. straminata,andI. biselata (Geometridae,Lepidoptera)

Pheromone compounds so far identified from most geometrid moths consist of all-Z diene, triene, or tetraene hydrocarbons with chain lengths of C₁₇ to C₂₁, and their monoepoxide derivatives biosynthesized from linoleic and linolenic acids. The present study reports the occurrence of olefinic acetates as sex pheromones in three species of Geometridae. (Z,Z)-9,11-tetradecadienyl acetate and (Z,Z)-7,9-dodecadienyl acetate found in female gland extracts ofIdaea aversata elicited significant responses from conspecific male antennae in gas chromatography with electroantennographic detection (GCEAD). In extracts ofI. straminata, (Z,Z)-7,9-dodecadienyl acetate, (E,Z)-7,9-dodecadienyl acetate, and (Z,Z)-7,9-dodecadienyl acetate were found, and the synthetic compounds elicited strong responses from conspecific male antennae. In the third species,I. biselata, only (Z,Z)-7,9-dodecadienyl acetate was found in the female extracts, and this compound elicited a strong EAD response from the conspecific male antenna. The identities of the pheromone components inI. aversata andI. straminata were further confirmed according to their characteristic ions after GC-MS analyses. Single sensillum recordings fromI. aversata showed two types of pheromone-detecting sensilla present on the male antenna. One type contained two receptor neurons, one of which was specifically tuned to (Z,Z)-9,11-tetradecadienyl acetate, the other to (Z,E)-9,11-tetradecadienyl acetate. A second type contained one neuron responding to (Z,Z)-7,9-dodecadienyl acetate. The two types were clearly different also with respect to external morphology, the former being considerably longer and having a larger base diameter. Also inI. straminata two physiological types of sensilla could be distinguished. One type contained two neurons, one of which responded to (Z,Z)-7,9-dodecadienyl acetate, the other to (Z,E)-9,11-tetradecadienyl acetate. The second type contained one neuron, responding to (Z,Z)-7,9-dodecadienyl acetate. No correlation between external morphology and physiological response of the investigated sensilla was observed inI. straminata. In field tests, a two-component blend containing (Z,Z)-9,11-tetradecadienyl acetate and (Z,Z)-7,9-dodecadienyl acetate in a ratio of 10:1 was attractive to males ofI. aversata. This two-component blend was also attractive to males ofI. straminata, but in a ratio of 1:1. High numbers of maleI. biselata were caught in traps baited with (Z,Z)-7,9-dodecadienyl acetate alone. The incorporation of deuterium labels into pheromone components after topical application of deuterium-labeled palmitic acid confirmed that the pheromone components ofI. aversata could be synthesized from this precursor, as has been previously observed for acetate pheromone components of many other moth species. Our results suggest that an evolutionary reversal back to the production of palmitic acid-derived pheromone components has occurred within the geometrid subfamily Sterrhinae.     

Pheromone reception in tobacco budworm moth,heliothis virescens

Eleclrophysiological recordings from single olfactory receptor cells were carried out in the male tobacco budworm moth,Heliothis virescens. Recordings were made primarily from the sensilla trichodea type 1, which are located in the characteristic circumferential rows on the antennae. They possess the longest sensilla hairs as revealed by scanning electron microscopy (SEM). The sensory cells of these sensilla responded specifically to pheromones. Only three types of receptor neurons were found, each tuned to one of the female-produced components. The majority (58%) of the neurons were tuned to the major component (Z)-11-hexadecenal (Z11-16:A1). Another large group (27%) responded specifically to stimulation with (Z)-9-tetradecenal (Z9-14: Al). These two compounds are the most important components of the pheromones as judged by their influence on the behavioral responses of the males. The third type of neurons responded specifically to (Z)-11-hexadecen-1-ol (Z11-16: OH), which may act either as a pheromone component or as an interspecific cue. None of the receptor neurons in the long sensilla trichodea responded specifically to the minor aldehyde components of the pheromone, which have subtle effects on behavior. Mixture experiments provided no evidence that minor components influence the receptor responses to the major components. Olfactory sensilla outside the crosswise rows were also characterized morphologically by SEM. Included in these were sensilla of different lengths, corresponding to a classification as s. basiconica and s. trichodea type 2. Electrophysiological recordings from these sensilla showed that they are involved primarily in host odor reception. However, a few of these neurons responded to pheromones.     

Caterpillar-Induced Plant Volatiles Attract Adult Tortricidae

Binary and ternary combinations of volatile organic compounds identified earlier from caterpillar-infested apple foliage caught more than one thousand individuals of both sexes of several adult tortricid leafroller species in several days of trials conducted in apple orchards in southern British Columbia. A series of combinations with phenylacetonitrile, benzyl alcohol, and/or 2-phenylethanol and acetic acid enabled substantial catches of both sexes of eye-spotted budmoth, Spilonota ocellana, oblique-banded leafroller, Choristoneura rosaceana and three-lined leafroller, Pandemis limitata. These findings suggest that new monitoring aides can be developed to seasonally track populations, enabling practical applications in surveillance of female leafroller populations for the first time. It may also be possible to develop suppression tools based on combinations of kairomone compounds originally identified from leafroller larval-damaged apple trees, given the level of attraction. The discovery of these adult tortricid attractants (aromatic compounds plus acetic acid) raises new ecological questions about evolved direct plant defences against herbivores. Larval feeding-induced attraction of adult herbivores produces signals that are potentially harmful to the plant by increasing herbivory in the same family and probably feeding guild, but evidence for effects on plant fitness is needed.     

Identification of Human-Derived Volatile Chemicals that Interfere with Attraction of <Emphasis Type="Italic">Aedes aegypti</Emphasis> Mosquitoes

It is known that human individuals show different levels of attractiveness to mosquitoes. In this study, we investigated the chemical basis for low attractiveness. We recorded behaviors of Aedes aegypti toward the hands of human volunteers and toward the volatile chemicals produced by their bodies. Some individuals, and their corresponding volatiles, elicited low upwind flight, relative attraction, and probing activity. Analyzing the components by gas chromatography coupled to electrophysiological recordings from the antennae of Aedes aegypti, enabled the location of 33 physiologically relevant compounds. The results indicated that higher levels of specific compounds may be responsible for decreased “attractiveness.” In behavioral experiments, five of the compounds caused a significant reduction in upwind flight of Aedes aegypti to attractive human hands. Thus, unattractiveness of individuals may result from a repellent, or attractant “masking,” mechanism.     

Odorant Binding Characteristics of Three Recombinant Odorant Binding Proteins in Microplitis mediator (Hymenoptera: Braconidae)

Odorant binding proteins (OBPs) are believed to be important for transporting semiochemicals through the aqueous sensillar lymph to the olfactory receptor cells within the insect antennal sensilla. In this study, three new putative OBP genes, MmedOBP8-10, were identified from a Microplitis mediator (Hymenoptera: Braconidae) antennal cDNA library. Quantitative real-time PCR (qRT-PCR) analysis revealed that all three of the OBP genes were expressed mainly in the antennae of adult wasps. The three OBPs were recombinantly expressed in Escherichia coli and purified by Ni ion affinity chromatography. Fluorescence competitive binding assays were performed using N-phenyl-naphthylamine as a fluorescent probe and 45 small organic compounds as competitors. These assays demonstrated that the three M. mediator OBPs can bind a broad range of odorant molecules with different binding affinities. They can bind the following ligands: nonane, farnesol, nerolidol, nonanal, β-ionone, acetic ether, and farnesene. In a Y-tube assay with these ligands as odor stimuli and paraffin oil as a control, all ligands, except nerolidol and acetic ether, were able to elicit behavioral responses in adult M. mediator. The wasps were significantly attracted to β-ionone, nonanal, and farnesene and repelled by nonane and farnesol. The results of this work provide insight into the chemosensory functions of the OBPs in M. mediator.     

Sex pheromone components ofEuxoa drewseni Chemical identification,electrophysiological evaluation,and field attractancy tests

Eleven compounds structurally similar to known lepidopterous pheromone components were identified in the extract from 18 calling female moths ofEuxoa drewseni (Staudinger). The identifications were done by gas chromatography-mass spectrometry and high-resolution gas chromatography with flame ionization and electroantennographic detectors simultaneously. Detector antennae were from five species of moths. In the field, male moths were specifically attracted to a three-component blend of dodecyl, (Z)-5-dodecenyl, and (Z)-7-tetradecenyl acetates in a ratio of 2∶6∶1. This blend at 1000 μg/rubber septum dispenser is recommended as a trap bait for monitoring purposes. Low concentrations of (Z)-7-dodecenyl acetate or (Z)-7-tetradecenol inhibited the attraction of moths to the three-component blend. (Z)-7-Pentadecenyl acetate functioned as a parapheromone in place of (Z)-7-tetradecenyl acetate in the pheromone blend, and they appear to react via the same antennal receptor.