星天牛对青皮垂柳挥发物的电生理及行为反应

【目的】考察星天牛Anoplophora chinensis对不同生理状态青皮垂柳Salix ohsidare挥发物的选择偏好性,深入探究星天牛对虫害青皮垂柳与健康青皮垂柳行为选择差异的原因。【方法】利用动态顶空吸附法,分别收集虫害和健康两种生理状态下的青皮垂柳枝条挥发物,通过气相色谱 质谱联用仪(GC-MS)对收集的挥发物样品进行鉴定与分析,采用触角电位仪(EAG)和Y型嗅觉仪分别分析星天牛对挥发物样品中鉴定的主要化合物的标准化合物的电生理以及行为反应,通过大笼行为实验和林间诱捕试验分析单一挥发性化合物及其双组分和三组分配方对星天牛成虫的诱捕效果。【结果】健康青皮垂柳枝条挥发物中共鉴定出3种主要化合物,包括α-蒎烯、3-蒈烯和樟脑,而虫害青皮垂柳枝条挥发物中鉴定出5种主要化合物包括α-蒎烯、β-蒎烯、3-蒈烯、β-罗勒烯和樟脑。另外虫害青皮垂柳枝条挥发物中的樟脑含量显著高于健康青皮垂柳枝条中的,3-蒈烯在两种挥发物中含量差异不显著,而健康青皮垂柳枝条挥发物中的α-蒎烯含量显著高于虫害青皮垂柳枝条中的。EAG实验表明,星天牛成虫对α-蒎烯、3-蒈烯和β-罗勒烯3种化合物的EAG反应相对值较高,并且随这3个化合物浓度的升高而逐渐增大;星天牛成虫对β-蒎烯和樟脑的EAG反应相对值差异不大,且这2个化合物浓度变化对EAG反应相对值无明显影响。Y型嗅觉仪实验表明,在1 mg/mL浓度下,α-蒎烯、3-蒈烯和β-罗勒烯吸引星天牛雄成虫数量均显著高于对照组（石蜡油）,β-罗勒烯吸引的星天牛雌成虫数量显著高于对照组;在10 mg/mL浓度下,3-蒈烯吸引的星天牛雄成虫数量显著高于对照组。大笼行为实验表明,三组分虫害配方D(α-蒎烯∶3-蒈烯∶β-罗勒烯=42∶30∶103)、α-蒎烯和β-罗勒烯吸引的星天牛成虫数量最多,显著高于双组分健康配方H(α-蒎烯∶3-蒈烯=105∶38)和3-蒈烯吸引的成虫数量。林间诱捕试验表明,α-蒎烯和虫害配方D对星天牛成虫的诱捕效果最好,诱捕的成虫数显著高于β-罗勒烯和健康配方H诱捕的成虫数,而3-蒈烯和空白对照组没有诱捕到星天牛成虫。【结论】虫害和健康青皮垂柳枝条挥发物中共有的α-蒎烯和虫害青皮垂柳枝条挥发物中特有的β-罗勒烯是对星天牛成虫具有引诱作用的两种重要寄主植物挥发性化合物,而3-蒈烯抑制了α-蒎烯对星天牛成虫的引诱作用。我们推测,虫害青皮垂柳挥发物中特有的β 罗勒烯是造成虫害青皮垂柳比健康青皮垂柳更容易受到星天牛危害的原因之一。     

松墨天牛成虫对幼虫虫粪挥发性物质的触角电位反应及林间驱避试验

为了研制松墨天牛Monochamus alternatus Hope驱避剂,本文利用触角电位技术和田间试验的方法研究了松墨天牛雌雄成虫对幼虫虫粪挥发性物质的触角电位反应及幼虫虫粪己烷提取物、合成化合物混合物的林间驱避作用。结果表明：α-蒎烯、β-蒎烯、3-蒈烯、柠檬烯和长叶烯均能引起松墨天牛雌雄成虫一定的触角电生理反应,而4-甲基-2,6-二叔丁基苯酚不能引起松墨天牛雌雄成虫的触角电生理反应。林间驱避试验结果说明,幼虫虫粪的己烷提取物处理过的树干上的刻槽数明显少于对照树干上的刻槽数,二者具有极显著差异;有合成化合物的混合物存在的诱捕器诱捕到的雌虫数（平均值3.80±1.02）与对照诱捕到的雌虫数（平均值16.80±1.16）差异极显著。结果显示α-蒎烯、β-蒎烯、3-蒈烯、柠檬烯、长叶烯和4-甲基-2,6-二叔丁基苯酚的混合物对松墨天牛雌虫具有驱避作用,有望开发出一类新的驱避剂。     

Pea aphid dropping behavior diminishes foraging efficiency of a predatory ladybeetle

Antipredator defensive behaviors are a well‐studied and often crucial part of prey life histories, but little has been done to quantify how such behaviors affect natural enemies, their foraging, and their effectiveness as biological control agents. We explored how the generalist predatory coccinellid Harmonia axyridis Pallas (Coleoptera: Coccinellidae) affects the dropping behavior of the pea aphid, Acyrthosiphon pisum (Harris) (Homoptera: Aphididae), and in turn, how that defensive behavior affects the foraging efficiency of the predator. Experimental arenas that allowed or prevented pea aphid dropping were compared to determine how dropping influences the foraging of multiple life stages of H. axyridis: second instars, fourth instars, and adults. Dropping reduced predation on aphids by all ladybeetle life stages. Despite older predators inducing more dropping, aphid dropping reduced predation by approximately 40% across all ladybeetle life stages. Aphid dropping and predator consumption of aphids were both correlated with how much the predator moved, which also increased with predator life stage. We suggest that the high rates of dropping induced by H. axyridis and the subsequent decrease in H. axyridis foraging efficiency may partially explain why H. axyridis is less effective at controlling pea aphids than it is at controlling other aphid species that do not drop.     

Callus in Rosmarinus officinalis L. (Lamiaceae): A morphoanatomical,histochemical and volatile analysis

This study aims to evaluate the anatomy of calli and their chemico-morphological characteristics after in vitro culture. Callus was induced from leaf explants of Rosmarinus officinalis derived from in vitro grown plants on media containing 2,4-dichlorophenoxyacetic acid (2,4D) and thidiazuron (TDZ) supplementation. Both capitate and peltate glandular trichomes were recognized in R. officinalis callus by light and electron microscopy. Histochemical tests showed positive reactions to lipophilic and terpenoid compounds for capitate trichomes and parenchyma or meristematic cells. Volatiles were isolated by simultaneous distillation–extraction and analysed by gas chromatography. Specifically, the use of 2,4D was shown to have a positive effect on the capacity of R. officinalis friable callus to produce volatile monoterpene compounds relative to TDZ. The main volatiles produced by callus were α-pinene, β-pinene and camphor produced in media containing 0.5 and 1.0 mg L^? 1 of 2,4D. Significant quantities of α-pinene, β-pinene and camphor were produced with 0.5 mg L^? 1 of 2,4D. On the basis of this accumulated evidence, it can be concluded that R. officinalis callus produces volatiles in developing glandular trichomes and that cellular aggregates and in vitro culture can be used for the production of volatiles under in vitro controlled conditions from selected plant material.     

Pseudotsuga menziesii (Pinaceae): Volatile Profiles,Antimicrobial Activity and Toxicological Evaluation of Its Essential Oil

The present article investigates the chemical composition of volatiles of essential oil (EO) and headspace (HS) fraction, as well as biological activities of EO obtained from needles with twigs of Pseudotsuga menziesii var. menziesii cultivated in Serbia. The major class of compounds was monoterpene hydrocarbons with α-terpinolene, sabinene and β-pinene (EO), and sabinene, α-terpinolene and β-pinene (HS) as the dominant volatiles. Tested EO exhibited mostly low antimicrobial potential against investigated strains (ATCC and respiratory isolates), where MICs ranged 1.25–20.00 mg/mL. Nevertheless, based on presented results, where antimicrobial testing was done for the first time on human respiratory system isolates, there is a potential of this EO to be used as an adjuvant in the treatment of human respiratory infections, especially those caused by Pseudomonas aeruginosa or Candida albicans strains. Regarding toxicological evaluation, EO showed moderate toxicity in Artemia salina toxicity bioassay (LC₅₀=347.41, after 24 h) as well as week toxicity against Drosophila melanogaster with the ability only to moderately delay larval and pupal development.     

Establishment of multicolored Asian lady beetle in Eastern North Carolina: Seasonal abundance and crop exploitation within an agricultural landscape

Seasonal abundance and cropexploitation of the multicolored Asian ladybeetle, Harmonia axyridis (Pallas)(Coccinellidae: Coleoptera), were identifiedduring its initial establishment in the easternNorth Carolina agroecosystem. Densities ofH. axyridis adults and larvae werecompared with densities of previouslyestablished predaceous coccinellids in wheat,potato, corn and soybean, which are thepredominant crops in this region. One-hundred-fifty whole plant samples werevisually inspected for coccinellid adults andlarvae in each crop on six farms every 7 to 14days. H. axyridis adults colonizedwheat, potato and corn, but reproduced only inwheat and potato. Soybean fields were notcolonized. The presence of H. axyridisin a crop was typically associated with anabundance of aphids, with the exception ofpotato, and no aphids were encountered insoybean. In addition to H. axyridis,four other lady beetle species, Coccinellaseptempunctata L., Coleomegilla maculata(DeGeer), Hippodamia convergens (Guerin)and Cycloneda munda L., were encounteredin the landscape. In wheat, potato and corn,densities of H. axyridis adults averagedthroughout the 1995 and 1996 seasons wereseven, ten and 28 times lower, respectively,than the season average density of the leastabundant species of previously established ladybeetle, whereas these densities averaged 82, 42and 356 times lower, respectively, than theaverage density of the most abundantestablished coccinellid species. H.axyridis is commonly encountered in theeastern North Carolina agricultural landscape,but its impact on the existing coccinellidassemblage cannot yet be determined. Theresults presented provide a baseline againstwhich the results of future studies can becompared to determine if H. axyridis isdisplacing established species.     

Effects of leaf conditions and flight activity on the behaviour of Platypus quercivorus (Murayama) (Coleoptera: Platypodidae)

The important role of semiochemicals in the interactions between plants and insects has been extensively investigated. The volatiles produced by oak trees are thought to attract the ambrosia beetle Platypus quercivorus (Murayama), which causes wilt disease in Quercus trees, resulting in widespread damage. In the present study, we hypothesized that (a) P. quercivorus is attracted to the leaf volatiles emitted by host trees and (b) the response of P. quercivorus to leaf volatiles is affected by flight. An experiment was performed to survey the preferences of both sexes of P. quercivorus for the leaf volatiles of Quercus crispula Blume at various stages of leaf deterioration, represented by different number of days after cutting. Additionally, the effect of flight on both sexes was evaluated by testing the beetle flight on a flight mill. The results showed that P. quercivorus was attracted to the volatiles emitted from fresh leaves and was not attracted to those emitted from dry leaves. This suggests that leaf volatiles from healthy hosts are primary attractants for P. quercivorus. Further, males exhibited increased olfactory responses to leaf volatiles as their flight duration increased, whereas the opposite pattern was observed in females. These results suggest that the different ecological roles of the sexes contribute to differences in olfactory responses.     

Volatile and Contact Chemicals Released by Nezara viridula (Heteroptera:Pentatomidae) Have a Kairomonal Effect on the Egg Parasitoid Trissolcus basalis (Hymenoptera: Scelionidae)

The responses of females of the egg parasitoid Trissolcus basalis (Wollaston) (Hymenoptera: Scelionidae) to volatile and contact chemicals from its host Nezara viridula (L.) (Heteroptera: Pentatomidae) were investigated in a Y-tube olfactometer and under open arena conditions. In the Y-tube tests, volatiles from virgin males and from females in a preovipositional state attracted T. basalis females, while volatiles from host virgin females did not. In an open arena, traces left by N. viridula adults in different physiological conditions function as contact cues inducing the wasps to remain longer in the arena and to change the pattern of their walking behavior. However, only contact kairomones from N. viridula mated females in a preovipositional condition induced an arrestment response characterized by an increase in patch searching time and turning rates and a reduction in linear speed. The chemical ecological implications of these results on this host–parasitoid association are discussed.     

Does application of methyl jasmonate to birch mimic herbivory and attract insectivorous birds in nature?

Earlier studies have suggested that insectivorous birds, similar to invertebrate predators and parasitoids, may be guided by herbivore-induced plant volatiles (HIPVs) to damaged, herbivore-rich trees. Recent studies have also shown that birds use olfaction more than previously thought, underlying the potential for HIPVs to be sensed by insectivorous birds and utilised during foraging for prey. The HIPV production in plants is mediated, at least partly, by the jasmonic acid signalling pathway, and similar HIPVs to those induced by herbivores can often be induced by exposing plants to methyl jasmonate (MeJa). We studied the effects of MeJa on volatile emission and bird attraction using mature mountain birches (Betula pubescens ssp. czerepanovii) under natural conditions in northern Finland. Experimental trees were assigned to four treatment groups: herbivore-damaged [autumnal moth (Epirrita autumnata)], higher dose of MeJa (30 mM), lower dose of MeJa (15 mM) and control. All trees had three branches covered with mesh bags, but there were larvae inside the bags only of the herbivore-damage treatment. Bird predation rate was monitored with artificial plasticine larvae which were checked daily for peck marks. Birds most often pecked the larvae in the herbivore-damaged trees, but the attractiveness of MeJa-treated trees did not differ from the control. High within-treatment variation in systemic HIPV emissions probably masked MeJa treatment effects. The bird predation rate was high in birches that emitted large amounts of α-pinene. Thus, α-pinene may be one cue used by birds to find herbivore-rich birches.     

Testing what we know about coffee volatiles affecting behaviour of Hypothenemus hampei

Coffee berry borer (CBB), Hypothenemus hampei (Ferrari) (Coleoptera: Scolytinae), is a major pest of coffee worldwide. CBB females use berry volatiles while searching for hosts. Coffee volatiles can be used for monitoring CBB populations. The main objective of this study was to test under laboratory and field conditions bioactive compounds for H. hampei. In the laboratory, CBB females were attracted to the methanol-ethanol blend (MEB), but not to methylcyclohexane, ethylbenzene, nonane, methyl salicylate, verbenone, α-pinene, farnesene, and frontalin compared to clean air. In contrast, CBB females preferred clean air over linalool. Females were attracted to most of the tested compounds combined with the MEB over clean air, except farnesene, α-pinene, and linalool. Females preferred clean air to α-pinene or linalool, and they showed no preference for clean air or farnesene. Females also preferred the MEB over linalool, verbenone, α-pinene, or farnesene when combined with MEB. The combination of tested compounds and the MEB did not increase the capture of CBB in the field. Interestingly, α-pinene and linalool alone, or combined, inhibited the capture of CBB females and non-target insects by trapping bait with the MEB. Thus, α-pinene or linalool can be used in a push-pull strategy considering the low impact over non-target insects.     

华山松木蠹象聚集信息素分离鉴定和引诱效果

为了研制华山松木蠹象Pissodes punctatus Langor et Zhang的引诱剂,对华山松木蠹象的虫粪和雄虫后肠挥发性物质进行了分析鉴定和室内外生物活性测试。经GC-MS测定,发现在华山松木蠹象的新鲜虫粪和雄虫后肠挥发性物质中,除了松树挥发性的单萜烯如α-蒎烯、β-蒎烯和3-蒈烯以外,还存在1-甲基-2-异丙烯基-环丁烷乙醇（grandisol）。室内Y-型嗅觉仪趋向实验表明,较低浓度的3-（+）-蒈烯、1-甲基-2-异丙烯基-环丁烷乙醇及其相应的醛1-甲基-2-异丙烯基-环丁烷2醛（grandisal）,引起华山松木蠹象的正趋向反应。林间引诱试验表明,1-甲基-2-异丙烯基-环丁烷乙醇和1-甲基2-异丙烯基-环丁烷2醛对华山松木蠹象具有一定的引诱作用。由此推断,1-甲基-2-异丙烯基-环丁烷乙醇可能是华山松木蠹象的集结信息素成分之一。     

马尾松树针叶挥发性化学物质对松毛虫赤眼蜂嗅觉及寄生行为的影响

应用Y型嗅觉仪测定松毛虫赤眼蜂Trichogramma dendrolimi Matsumura对9种马尾松树针叶挥发性物质对的嗅觉行为反应,确定了4种对于松毛虫赤眼蜂有影响活性的马尾松树针叶挥发性物质。它们分别是α-蒎烯,β-蒎烯,柠檬烯,α-萜品醇乙酸酯4种物质,其中尤以α-蒎烯和β-蒎烯2种物质作用最显著。产卵生测实验中,4种活性挥发性物质的混合物分别与它们的单一成分、α-蒎烯、β-蒎烯分别与除去它们后的混合物进行比较。结果显示,与对照相比,它们均能对松毛虫赤眼蜂的产卵寄生率产生显著影响,该结果也和Y型嗅觉仪下的实验结果基本一致。但在单一物质和混合物对松毛虫赤眼蜂的寄生率影响比较中,混合物并没有使松毛虫赤眼蜂产生最高的寄生率,这说明可能是某种单一物质在其寄生过程中起主导作用。     

Variation in the olfactory response of 13 populations of the predatory mite Amblyseius womersleyi to Tetranychus urticae-infested plant volatiles (Acari: Phytoseiidae, Tetranychidae)

We studied the response of the predatory mite Amblyseius womersleyi collected in 13 different sites in Japan toward Tetranychus urticae-infested kidney bean leaf volatiles in a Y-tube olfactometer. The predatory mites were collected from eight plant species infested by one of three tetranychid mite species. The predators' responses to the infested-leaf volatiles varied from 33% to 97% among the populations. The predators collected at 10 sites showed a significant preference for infested-leaf volatiles, whereas those collected at three tea plantations did not distinguish between the infested- and uninfested-leaf volatiles. We discussed the possible factors that affected the olfactory response of A. womersleyi towards the infested leaf volatiles.     

Mating and adult feeding behaviour influence pheromone production in female Asian longhorn beetle Anoplophora glabripennis (Coleoptera: Cerambycidae)

1. The Asian longhorn beetle (ALB) Anoplophora glabripennis Motschulsky is a destructive invasive species worldwide. Female ALB produce a pheromone component, α-longipinene, in the genitalia. However, the origin and factors, such as age, mating, adult feeding and host plant, influencing the production of this compound are unclear.
2. Our results showed that virgin female ALB consistently produced α-longipinene at various ages after feeding for several days post eclosion, but unfed adult females never produced this compound. Mating significantly reduced the amount of α-longipinene in female genitalia.
3. α-Longipinene was the most dominant compound in the volatiles emitted by females, but not in those emitted by males or host twigs (Acer pensylvanicum L.). The proportion of α-longipinene among the beetle-released sesquiterpenes that were known to be male antennally active was significantly greater than that emitted by ALB damaged, mechanically damaged or control twigs.
4. These results suggest that ALB females probably derive α-longipinene or a precursor from hosts via adult feeding, and release it at a significantly different ratio from that found in host volatiles. The various ratios of α-longipinene produced by beetles and host twigs may encode information pertaining to multiple purposes such as aggregation, mate and host location.

     

Response of Neoseiulus fallacis Garmen and Galendromus occidentalis Nesbitt (Acari: Phytoseiidae) to Tetranychus urticae Koch (Acari: Tetranychidae)-Damaged Hop Humulus lupulus (L.) (Urticales: Cannabaceae)

Abstract 1 The response of Neoseiulus fallacis Garmen and Galendromus occidentalis (Acari: Phytoseiidae) to Tetranychus urticae Koch (Acari: Tetranychidae)‐damaged and undamaged hop, Humulus lupulus (L.), plants was tested using a Y‐tube olfactometer. 2 Neoseiulus fallacis but not G. occidentalis was attracted to volatiles from T. urticae‐damaged hop plants when paired with undamaged plants. 3 The response of N. fallacis to these volatiles was stronger for plants severed at the soil surface than for intact plants. 4 There was no difference in the response of N. fallacis to severed or intact hop plants that had no spider mite damage, indicating that artificial wounding by severing alone does not elicit the production of attractive volatiles detectable to N. fallacis. These results are consistent with the existence of cross‐talk between signalling pathways initiated by feeding damage and artificial wounding that result in elevated levels of predator‐attracting volatiles.     

青杨脊虎天牛对植物源挥发物的EAG和行为反应

测定了青杨脊虎天牛Xylotrechus rusticus （L.）雌、雄成虫对其寄主杨树中的水杨醛（0.95 μmol/μL）和非寄主植物中0.3 μmol/μL的叶绿醇、0.4 μmol/μL的水芹烯和0.6 μmol/μL的 R 型α-蒎烯、S 型α-蒎烯、S型β-蒎烯、3-蒈烯、罗勒烯、香草烯和松节油等10种植物挥发性气味物质的触角电位（EAG）反应。结果表明,与对照相比,这10种植物挥发物多能引起成虫明显的EAG反应( P<0.05,P<0.01 ),其中雌虫对松节油、水杨醛、R 型α-蒎烯和 S 型α-蒎烯的EAG反应较强; 雄虫对 R 型α-蒎烯的EAG反应最强,松节油次之。根据雌虫对这10种挥发物EAG反应的强弱,进一步测定了雌虫对0.00006、0.0006、0.006、0.06、0.6、0.12 μmol/μL的松节油、R 型α-蒎烯、S 型α-蒎烯以及0.000095、0.00095、0.0095、0.095、0.95、0.19 μmol/μL的水杨醛的EAG和行为反应。结果表明,雌虫对松节油、水杨醛和 R 型α-蒎烯的EAG反应随气味物质浓度的增加而增加,水杨醛浓度增加到0.95 μmol/μL、松节油和 R 型α-蒎烯浓度增加到0.6 μmol/μL以后,EAG反应值趋于平稳;对 S 型α-蒎烯的反应随浓度的增加而呈线性增加。水杨醛浓度低于0.095时,对雌虫没有明显的定向作用( P>0.05 ),高于此浓度时表现为驱避作用( P<0.05 ); 松节油在浓度低于或等于0.6 μmol/μL时对雌虫表现为驱避作用,浓度为0.6时驱避效果最佳（ P<0.01 ）。雌虫对 R 型α-蒎烯和 S 型α-蒎烯没有明显的定向行为反应。     

Plant volatiles in the sexual communication of Melolontha hippocastani: response towards time-dependent bouquets and novel function of (Z)-3-hexen-1-ol as a sexual kairomone

1. Swarming males of Melolontha hippocastani are known to locate females that stay feeding within the host trees by orienting towards damage‐induced plant volatiles (green leaf volatiles) and a sex pheromone. Thus, volatiles emitted by freshly damaged leaves might indicate to a male the presence of currently feeding females. 2. The hypothesis was studied that volatiles from freshly damaged leaves are more attractive to males than volatiles from old damaged leaves. The odour bouquets of damaged leaves from three plant species that have been shown to attract male M. hippocastani in the field were analysed 10 min (fresh damage) and 1.5 h (old damage) after damaging, using coupled gas chromatography–mass spectrometry. The results showed clear differences between the bouquets: the bouquet of freshly damaged leaves of all species consisted of typical leaf aldehydes, i.e. hexanal, (Z)‐3‐hexenal, (Z)‐2‐hexenal, (E)‐2‐hexenal, the leaf alcohol (Z)‐3‐hexen‐1‐ol, and the corresponding acetate. One and a half hours after damage, aldehydes had almost vanished and (Z)‐3‐hexen‐1‐ol and (Z)‐3‐hexenyl acetate predominated; however males of M. hippocastani were equally attracted to traps baited with volatiles from old and freshly damaged leaves in field experiments. When traps were baited with synthetic volatile mixtures mimicking the bouquets of old and freshly damaged leaves, M. hippocastani males even preferred the old damage mixture. 3. Experiments addressing the role of individual green leaf volatiles revealed that only (Z)‐3‐hexen‐1‐ol was highly attractive while the other compounds tested individually were behaviourally inactive, however all tested compounds elicited comparable electrophysiological responses on male M. hippocastani antennae. 4. In analogy to the term aggregation kairomone used for feeding‐induced plant volatiles that attract both sexes of an insect, the term sexual kairomone is suggested to describe the novel function of (Z)‐3‐hexen‐1‐ol in the sexual communication of M. hippocastani.     

New metabolites of α-pinene produced by the mountain pine beetle,Dendroctonus ponderosae (Coleoptera: Scolytidae)

Emergent females of the mountain pine beetle, Dendroctonus ponderosae, contained five previously undetected volatiles: toluene, 4-methylene-6,6-dimethylbicyclohept-2-ene (verbenene), p-mentha-1,5,8-triene, o- and p-cymene. Exposure of wild or axenically reared beetles to protio- and deuterio-α-pinene or protio- and deuterio-trans-verbenol indicated that all compounds except toluene were produced from α-pinene, with trans-verbenol as a probable intermediate. The ratio between these α-pinene metabolites was insensitive to the level of α-pinene to which the beetles were exposed, suggesting a tightly regulated enzymatic and/or acid-catalyzed conversion of α-pinene. Exposure of females to either enantiomer of α-pinene or to the same amount of (±)-α-pinene indicated that female mountain pine beetles possess two enantiospecific enzyme systems for processing α-pinene. Production of p-cymene constitutes the first record in an insect of an aromatic volatile produced from a monoterpene hydrocarbon.     

Differential sensitivity of an invasive and an indigenous ladybeetle to two reduced‐risk insecticides

The invasive multicoloured Asian lady beetle, Harmonia axyridis (Pallas), and the indigenous twelve spotted lady beetle, Coleomegilla maculata DeGeer (Col., Coccinellidae), are two important generalist predators commonly found in apple orchards in Quebec, Canada. Both species are exposed to two reduced‐risk insecticides, recently adopted to control codling moth, Cydia pomonella (L.) (Lep., Tortricidae) in south‐eastern Canada. Chlorantraniliprole (Altacor^® 35 WG), an anthranilic diamide insecticide, causes paralyses of the muscle cells by interfering with the insect ryanodine receptors, whereas novaluron (Rimon^® EC 10), a benzoylphenyl urea, inhibits the chitin synthesis. The aim of this study was to compare the sensitivity of both the invasive ladybeetle H. axyridis and the indigenous C. maculata to reduced‐risk insecticides through the assessment of lethal effect on eggs and larvae following topical contact, ingestion of treated prey and exposure to fresh residues, at field rates (50.75 g a.i./ha chlorantraniliprole and 100 g a.i./ha novaluron) in laboratory conditions. Eggs of both species were not affected. Following 6 days of residual contact, chlorantraniliprole and novaluron caused more than 98% mortality to larvae of both ladybeetle species. In topical contact and ingestion trials, chlorantraniliprole caused less than 18% mortality to larvae of the two species after 6 days following exposure. Novaluron had a drastically different impact on the two predators. It did not affect the indigenous C. maculata, whereas it killed 91% and 96% of H. axyridis individuals after 6 days, respectively, following topical contact and ingestion. These results illustrate a differential sensitivity to novaluron between two relatively close species (subfamily Coccinellinae), a potential impact on the invasion process by H. axyridis, and consequently on the ladybeetle assemblage in the field.     

The influence of host plant species on parasitism of pollen beetles (Meligethes spp.) by Phradis morionellus

We investigated the response of the specialist insect predator Oligota kashmirica benefica (Coleoptera: Staphylinidae) to volatiles from lima bean leaves infested with the spider mite Tetranychus urticae (Acari: Tetranychidae), both in a Y-tube olfactometer and in a field in Kyoto, Japan. Adult male and female predators were significantly more attracted to T. urticae-infested leaves than to clean air. Adult male and female predators were not more attracted to uninfested leaves, artificially damaged leaves, or the spider mites and their visible products when compared to clean air. In a field trap experiment, 12 adult predators were caught in three traps containing T. urticae-infested lima bean plants over 13 days, whereas no adult predators were trapped in three traps containing uninfested lima bean plants during the same period. These results showed that O. kashmirica benefica adults responded to herbivore-induced plant volatiles from T. urticae-infested lima bean leaves under both laboratory and field conditions.