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1.
In Y-tube olfactometer bioassays, adult Apanteles carpatus (Say), were attracted to beaver or rabbit pelts infested with larvae of the casemaking clothes moth (CCM) Tinea pellionella L. Porapak Q-captured volatiles from a CCM-infested beaver pelt were also very attractive, whereas isolated CCM larvae or larval feces were not. Coupled gas chromatographic–electroantennographic detection (GC-EAD) analysis of the Porapak Q volatile extract revealed two compounds that elicited responses by A. carpatus antennae. Coupled GC–mass spectrometry (MS) in electron impact and chemical ionization modes of these compounds indicated, and GC-MS and GC-EAD of authentic standards confirmed, that they were nonanal and geranylacetone. While each compound singly did not attract A. carpatusa 1:1 blend of both compounds was as attractive as the volatile extract. Because these compounds are host habitat-derived A. carpatus must be a habitat rather than host specialist, responding to kairomonal indicators of localized and specific habitats such as animal hair or feather. The tritrophic interaction between A. carpatusits clothes moth hosts and their animal-derived habitats is similar to the well-studied relationship between parasitoids of insect herbivores and their host plant habitats. 相似文献
2.
We identified, synthesized, determined the diel periodicity of release, and tested the bioactivity of components of the male-produced
sex pheromone of Hedypathes betulinus (Coleoptera: Cerambycidae: Lamiinae). Gas chromatographic-mass spectrometric analysis of headspace volatiles from adult beetles
showed three male-specific compounds, which were identified as ( E)-6,10-dimethyl-5,9-undecadien-2-yl acetate (major component), ( E)-6,10-dimethyl-5,9-undecadien-2-one (geranylacetone), and ( E)-6,10-dimethyl-5,9-undecadien-2-ol. Release of these chemicals was dependent on time of the photoperiod and presence of the
host plant. Pheromone release took place primarily during the photophase, with maximum release occurring between 4 and 6 hr
after the onset of photophase. The amount of pheromone released by males was much greater when they were in the presence of
their host plant than when they were not. In Y-tube olfactometer tests, a ternary mixture of the compounds was attractive
to female beetles, although the individual compounds were not attractive by themselves. Addition of volatiles from the host
plant greatly increased the attractiveness of the ternary pheromone mixture and of the major pheromone component alone. 相似文献
3.
The odor produced by a plant under herbivore attack is often used by parasitic wasps to locate hosts. Any type of surface damage commonly causes plant leaves to release so-called green leaf volatiles, whereas blends of inducible compounds are more specific for herbivore attack and can vary considerably among plant genotypes. We compared the responses of naïve and experienced parasitoids of the species Cotesia marginiventris and Microplitis rufiventris to volatiles from maize leaves with fresh damage (mainly green leaf volatiles) vs. old damage (mainly terpenoids) in a six-arm olfactometer. These braconid wasps are both solitary endoparasitoids of lepidopteran larvae, but differ in geographical origin and host range. In choice experiments with odor blends from maize plants with fresh damage vs. blends from plants with old damage, inexperienced C. marginiventris showed a preference for the volatiles from freshly damaged leaves. No such preference was observed for inexperienced M. rufiventris. After an oviposition experience in hosts feeding on maize plants, C. marginiventris females were more attracted by a mixture of volatiles from fresh and old damage. Apparently, C. marginiventris has an innate preference for the odor of freshly damaged leaves, and this preference shifts in favor of a blend containing a mixture of green leaf volatiles plus terpenoids, after experiencing the latter blend in association with hosts. M. rufiventris responded poorly after experience and preferred fresh damage odors. Possibly, after associative learning, this species uses cues that are more directly related with the host presence, such as volatiles from host feces, which were not present in the odor sources offered in the olfactometer. The results demonstrate the complexity of the use of plant volatiles by parasitoids and show that different parasitoid species have evolved different strategies to exploit these signals. 相似文献
4.
The female parasitic wasp Cotesia kariyai discriminated between the volatiles of corn leaves infested by younger host larvae Pseudaletia separata (first to fourth instar) and uninfested leaves in a Y-tube olfactometer; the wasps were attracted to the infested leaves. In contrast, when corn plants were infested by the later stages (fifth and sixth instar) of the armyworm, the wasps did not distinguish between infested corn leaves and uninfested corn leaves in the olfactometer. Mechanically damaged leaves were no more attractive than undamaged leaves, and host larvae or their feces were not attractive to the parasitoid. Through chemical analysis, the herbivore-induced plant volatiles were identified in the headspace of infested corn leaves. The herbivore-induced volatiles (HIVs) constituted a larger proportion of the headspace of corn leaves infested by early instar armyworms than of corn leaves infested by late instar armyworms. Application of third-instar larval regurgitant onto artificially damaged sites of leaves resulted in emission of parasitoid attractants from the leaf, whereas leaves treated with sixth-instar regurgitant did not. The function of this herbivore-stage related specificity of herbivore-induced synomones is discussed in a tritrophic context. 相似文献
5.
Olfactory attraction of female diamondback moths ( Plutella xylostella) to odors of intact and homogenized host plants, as well as individual compounds characteristic of host plants, were investigated by behavioral and electrophysiological methods. Moths were attracted to odors of Brassica juncea and B. napus seedlings in a Y-tube bioassay. Solvent fractions of homogenized B. juncea leaves were attractive to moths whether or not isothiocyanates (IC) were present. Moths were attracted in Y-tube bioassays and to field traps baited with individual ICs. Volatiles from B. juncea and B. napus elicited an electroantennogram (EAG) response and were attractive in the Y-tube bioassay. Allyl IC was shown to be the attractive component in homogenized plant volatiles but was found to be virtually absent from intact plant volatiles. Gas chromatographic fractionation of intact plant volatiles revealed a terpene-containing fraction to be most attractive to the moths. We were unable to isolate individual attractive compounds from this fraction. Our results suggest that certain elements of this fraction, possibly in combination, are important olfactory cues for host-plant finding by the diamondback moth with mustard oils playing an important and possibly synergistic role, particularly when plants are damaged. 相似文献
6.
We determined that location of host ( Cydia pomonella) eggs by Ascogaster quadridentata is mediated by kairomones, investigated potential sources of the kairomones and identified a blend of kairomones from the source that was attractive to A. quadridentata. In Y-tube olfactometer bioassays, female A. quadridentata were attracted to Porapak Q-collected volatiles from female C. pomonella scales and eggs, but not to C. pomonella sex pheromone. Scales of C. pomonella were also attractive to male A. quadridentata. Coupled gas chromatographic–electroantennographic detection analysis of scale volatile extracts revealed numerous compounds that elicited responses from male or female A. quadridentata antennae, including heptanal, octanal, nonanal, decanal, undecan-2-one, dodecanal, pentadecan-2-one, ( Z)-6-pentadecen-2-one, ( Z)-9-hexadecenal, ( Z)-6-heptadecen-2-one, and 3,7,11-trimethyl-2 E,6 E,10-dodecatrien-1-ol acetate. A synthetic blend of these compounds at quantities and ratios equivalent to Porapak Q scale volatile extract was attractive to female A. quadridentata in a Y-tube olfactometer bioassay. 相似文献
7.
Parasitoids are known to exploit volatile cues emitted by plants after herbivore attack to locate their hosts. Feeding and oviposition of a polyphagous herbivore can induce the emission of odor blends that differ among distant plant species, and parasitoids have evolved an incredible ability to discriminate them and locate their hosts relying on olfactive cues. We evaluated the host searching behavior of the egg parasitoid Cosmocomoidea annulicornis (Ogloblin) (Hymenoptera: Mymaridae) in response to odors emitted by two taxonomically distant host plants, citrus and Johnson grass, after infestation by the sharpshooter Tapajosa rubromarginata (Signoret) (Hemiptera: Cicadellidae), vector of Citrus Variegated Chlorosis. Olfactory response of female parasitoids toward plants with no herbivore damage and plants with feeding damage, oviposition damage, and parasitized eggs was tested in a Y-tube olfactometer. In addition, volatiles released by the two host plant species constitutively and under herbivore attack were characterized. Females of C. annulicornis were able to detect and significantly preferred plants with host eggs, irrespectively of plant species. However, wasps were unable to discriminate between plants with healthy eggs and those with eggs previously parasitized by conspecifics. Analysis of plant volatiles induced after sharpshooter attack showed only two common volatiles between the two plant species, indole and β-caryophyllene. Our results suggest that this parasitoid wasp uses common chemical cues released by many different plants after herbivory at long range and, once on the plant, other more specific chemical cues could trigger the final decision to oviposit. 相似文献
8.
Anagrus nilaparvatae, an egg parasitoid of the rice brown planthopper Nilaparvata lugens, was attracted to volatiles released from N. lugens-infested plants, whereas there was no attraction to volatiles from undamaged plants, artificially damaged plants, or volatiles
from N. lugens nymphs, female adults, eggs, honeydew, and exuvia. There was no difference in attractiveness between plants infested by N. lugens nymphs or those infested by gravid females. Attraction was correlated with time after infestation and host density; attraction
was only evident between 6 and 24 hr after infestation by 10 adult females per plant, but not before or after. Similarly,
after 24 hr of infestation, wasps were attracted to plants with 10 to 20 female planthoppers, but not to plants with lower
or higher numbers of female planthoppers. The attractive time periods and densities may be correlated with the survival chances
of the wasps' offspring, which do not survive if the plants die before the wasps emerge. Wasps were also attracted to undamaged
mature leaves of a rice plant when one of the other mature leaves had been infested by 10 N. lugens for 1 d, implying that the volatile cues involved in host location by the parasitoid are systemically released. Collection
and analyses of volatiles revealed that 1 d of N. lugens infestation did not result in the emission of new compounds or an increase in the total amount of volatiles, but rather the
proportions among the compounds in the blend were altered. The total amounts and proportions of the chemicals were also affected
by infestation duration. These changes in volatile profiles might provide the wasps with specific information on host habitat
quality and thus could explain the observed behavioral responses of the parasitoid. 相似文献
9.
Olfactory responses of the cereal stemborer parasitoid Cotesia
sesamiae to volatiles emitted by gramineous host and nonhost plants of the stemborers were studied in a Y-tube olfactometer. The host plants were maize ( Zea mays) and sorghum ( Sorghum bicolor), while the nonhost plant was molasses grass ( Melinis minutiflora). In single-choice tests, females of C. sesamiae chose volatiles from infested and uninfested host plants and molasses grass over volatiles from the control (soil). In dual-choice tests, the wasp preferred volatiles from infested host plants to those from uninfested host plants. There was no discrimination between molasses grass volatiles and those of uninfested maize, uninfested sorghum, or infested maize. The wasp preferred sorghum volatiles over maize. Combining uninfested maize or sorghum with molasses grass did not make volatiles from the combination more attractive as compared to only uninfested host plants. Infested maize alone was as attractive as when combined with molasses grass. Infested sorghum was preferred over its combination with molasses grass. Local growth conditions of the molasses grasses influenced attractiveness to the parasitoids. Volatiles from Thika molasses grass were attractive, while those from Mbita molasses grass were not. Growing the Thika molasses grass in Mbita rendered it unattractive and vice versa with the Mbita molasses grass. This is a case of the same genotype expressing different phenotypes due to environmental factors. 相似文献
10.
The tea weevil, Myllocerinus aurolineatus (Voss) (Coleoptera: Curculionidae), is a leaf-feeding pest of Camellia sinensis (O.Ktze.) with aggregative behaviors that can seriously reduce tea yield and quality. Although herbivore-induced host plant
volatiles have been shown to attract conspecific individuals of some beetle pests, especially members of the Chrysomelidae
family, little is known about the volatiles emitted from tea plants infested by M. aurolineatus adults and their roles in mediating interactions between conspecifics. The results of behavioral bioassays revealed that
volatile compounds emitted from tea plants infested by M. aurolineatus were attractive to conspecific weevils. Volatile analyses showed that infestations dramatically increased the emission of
volatiles, ( Z)-3-hexenal, (Z)-3-hexenol, ( E)-β-ocimene, linalool, phenylethyl alcohol, benzyl nitrile, indole, ( E, E)-α-farnesene, ( E)-nerolidol, and 31 other compounds. Among the induced volatiles, 12 chemicals, including γ-terpinene, benzyl alcohol, ( Z)-3-hexenyl acetate, myrcene, benzaldehyde, ( Z)-3-hexenal, and ( E, E)-α-farnesene, elicited antennal responses from both sexes of the herbivore, whereas ( E)-β-ocimene elicited antennal responses only from males. Using a Y-tube olfactometer, we found that six of the 13 chemicals,
γ-terpinene, benzyl alcohol, ( Z)-3-hexenyl acetate, myrcene, benzaldehyde, and ( Z)-3-hexenal, were attractive to both males and females; two chemicals, ( E/Z)-β-ocimene and ( E, E)-α-farnesene, were attractive only to males; and four chemicals, ( E)-4,8-dimethyl-1,3,7-nonatriene, phenylethyl alcohol, linalool, and (Z)-3-hexenol, were attractive only to females. The findings
provide new insights into the interactions between tea plants and their herbivores, and may help scientists develop new strategies
for controlling the herbivore. 相似文献
11.
Plants infested with herbivorous arthropods emit complex blends of volatile compounds, which are used by several natural enemies
as foraging cues. Despite detailed knowledge on the composition and amount of the emitted volatiles in many plant-herbivore
systems, it remains largely unknown which compounds are essential for the attraction of natural enemies. In this study, we
used a combination of different fractionation methods and olfactometer bioassays in order to examine the attractiveness of
different compositions of volatile blends to females of the parasitoid Cotesia marginiventris. In a first step, we passed a volatile blend emitted by Spodoptera littoralis infested maize seedlings over a silica-containing filter tube and subsequently desorbed the volatiles that were retained
by the silica filter (silica extract). The volatiles that broke through the silica filter were collected on and subsequently
desorbed from a SuperQ filter (breakthrough). The silica extract was highly attractive to the wasps, whereas the breakthrough
volatiles were not attractive. The silica extract was even more attractive than the extract that contained all herbivore-induced
maize volatiles. Subsequently, we fractioned the silica extract by preparative gas-chromatography (GC) and by separating more
polar from less polar compounds. In general, C. marginiventris preferred polar over non-polar compounds, but several fractions were attractive to the wasp, including one that contained
compounds emitted in quantities below the detection threshold of the GC analysis. These results imply that the attractiveness
of the volatile blend emitted by Spodoptera-infested maize seedlings to C. marginiventris females is determined by a specific combination of attractive and repellent/masking compounds, including some that are emitted
in very small amounts. Manipulating the emission of such minor compounds has the potential to greatly improve the attraction
of certain parasitoids and enhance biological control of specific insect pests. 相似文献
12.
Trap cropping and biological control can provide a sustainable means of controlling insect pests. Insects in the genus Lygus (Hemiptera: Miridae) are major pests on cotton and horticultural crops throughout the United States, and pesticide resistance within Lygus populations necessitates more sustainable long-term management techniques. Here, we explore behavioral responses of Lygus bugs ( L. rubrosignatus Knight) and an introduced parasitoid, Peristenus relictus (Hymenoptera: Braconidae), to a common field edge plant, Erigeron annuus, which has the potential to serve as a trap host. Erigeron annuus is attractive to Lygus in the field, with Lygus preferentially moving to Erigeron patches compared to more abundant cotton plants. To determine the role of odor cues in mediating this attraction, we collected volatiles from E. annuus with and without Lygus damage, and then tested the attractiveness of these volatiles vs. those of cotton to Lygus females and female P. relictus wasps using Y-tube and wind tunnel bioassays. We found that undamaged E. annuus emits high concentrations of a complex volatile blend (60+ compounds), with novel compounds induced and constitutive compounds up-regulated in response to damage. Additionally, both female Lygus bugs and female P. relictus wasps are highly attracted to E. annuus volatiles over those of cotton in almost every combination of damage treatments. Our results suggest that Erigeron annuus would be an effective trap plant to control Lygus in cotton, since it is highly attractive to both the pest and its natural enemy. 相似文献
13.
The responses of female Aphidius ervi to odors from a host food plant ( Vicia faba), host aphids ( Acyrthosiphon pisum), nonhost aphids ( Aphis fabae), and aphid-plant complexes were investigated in a specially designed wind tunnel and a Y-tube olfactometer. In single-target (no-choice) and two-target (dual-choice) experiments, plant volatiles played a crucial role in the host foraging behavior of A. ervi. The odor from the A. pisum-plant complex elicited the strongest responses by A. ervi females, followed by the odor from plants previously damaged by the feeding of A. pisum. There was a significantly weaker response to odor from A. pisum in the absence of the plant and to undamaged plants. Similarly, mechanically damaged plants and plants infested with the nonhost aphid A. fabae did not elicit strong responses. A plant that had been damaged by A. pisum and subsequently washed with distilled water was as attractive as an unwashed, previously infested plant. Aphidius ervi probably overcomes the reliability-detectability problem by selectively responding to herbivore-induced, volatile, semiochemical cues emitted by the first trophic level and by distinguishing between the volatiles induced by host and nonhost aphids. 相似文献
14.
Y-tube olfactometer bioassays and combined gas chromatography–electroantennographic detector (GC-EAD) analyses were performed to investigate the specific odors utilized as host location cues by the bark beetle parasitoid, Roptrocerus xylophagorum, originating from the southeastern United States. R. xylophagorum parasitizes several economically important holarctic bark beetle species and females oviposit preferentially on late larval stages. Both female and male parasitoids were tested with volatiles derived from host infestations of either Dendroctonus frontalis, the southern pine beetle, or Ips grandicollis, the southern pine engraver. Tested volatiles were steam distillates from the bark of loblolly pine, Pinus taeda, infested with larvae of the respective bark beetle species. Combined gas chromatography–mass spectrometry (GC-MS) was employed for identification and quantification of the compounds in the steam distillates. To confirm the EAD activity of identified compounds, GC-EAD analyses were repeated with a synthetic blend composed predominantly of compounds in the crude extracts that had revealed apparent electrophysiological activity. In Y-olfactometer bioassays, female parasitoids were attracted to both of the above-mentioned distillates. Male parasitoids were tested with one of the distillates but failed to respond. In GC-EAD analyses, the sexes displayed similar relative sensitivities to the components of the blends. Males exhibited generally higher amplitudes of response to the tested compounds than females. Monoterpene hydrocarbons associated with the constitutive resin of the host tree did not elicit significant EAD responses. Compounds known to be associated specifically with the host–tree complex, such as certain oxygenated monoterpenes, generated the greatest EAD responses. Female parasitoids were attracted by a synthetic blend composed of several of the EAD active oxygenated monoterpenes. 相似文献
15.
We tested the hypotheses that host-searching behavior of the egg parasitoids Telenomus podisi and Trissolcus basalis may be differentially influenced by the different blends of volatiles released from the metathoracic glands of adult stink
bug host species. We further studied whether such a differential response is due to different individual components of these
glands and whether these responses reflect host preferences. Y-tube olfactometer bioassays were carried out with crude extracts
of metathoracic glands of five different host species of neotropical stink bugs. Additionally, we tested the parasitoids’
responses to synthetic standards of individual compounds identified in these stink bug glands. Results showed that females
of T. basalis and T. podisi responded differentially to crude gland extracts of the different species of host stink bugs and to the compounds tested.
The parasitoid T. basalis showed a positive taxic behavior to Nezara viridula methathoracxic gland extracts of a host species preferred in the field, i.e., N. viridula. Furthermore, T. basalis responded positively to 4-oxo-( E)-2-hexenal and ( E)-2-decenal, two components of N. viridula glandular secretion. Higher residence time, reduced linear velocity, and higher tortuosity in the arm of the olfactometer
supplied with 4-oxo-( E)-2-hexenal showed that this compound modifies the kinetics of some traits of T. basalis walking pattern and suggests that it might stimulate the searching behavior of this parasitoid. The parasitoid T. podisi was attracted to crude gland extracts of the preferred host ( Euschistus heros) and also to 4-oxo-( E)-2-hexenal. Additionally, this parasitoid responded positively to ( E)-2-hexenal and to the hydrocarbon tridecane, both of which are defensive compounds released from the metathoracic glands
by several stink bugs. The results indicate some degree of specialization in the response of two generalist parasitoid species
toward defensive secretions of stink bugs. 相似文献
16.
The annual bluegrass weevil (ABW), Listronotus maculicollis Kirby, is an economically important pest of short cut turfgrass. Annual bluegrass, Poa annua L., is the most preferred and suitable host for ABW oviposition, larval survival and development. We investigated the involvement of grass volatiles in ABW host plant preference under laboratory and field conditions. First, ovipositional and feeding preferences of ABW adults were studied in a sensory deprivation experiment. Clear evidence of involvement of olfaction in host recognition by ABW was demonstrated. Poa annua was preferred for oviposition over three bentgrasses, Agrostis spp., but weevils with blocked antennae did not exhibit significant preferences. ABW behavioral responses to volatiles emitted by Agrostis spp. and P. annua were examined in Y-tube olfactometer assays. Poa annua was attractive to ABW females and preferred to Agrostis spp. cultivars in Y-tube assays. Headspace volatiles emitted by P. annua and four cultivars of Agrostis stolonifera L. and two each of A. capillaris L. and A. canina L. were extracted, identified and compared. No P. annua specific volatiles were found, but Agrostis spp. tended to have larger quantities of terpenoids than P. annua. ( Z)-3-hexenyl acetate, phenyl ethyl alcohol and their combination were the most attractive compounds to ABW females in laboratory Y-tube assays. The combination of these compounds as a trap bait in field experiments attracted adults during the spring migration, but was ineffective once the adults were on the short-mown turfgrass. Hence, their usefulness for monitoring weevil populations needs further investigation. 相似文献
17.
Several studies have shown that herbivore-induced plant volatiles act directly on herbivores and indirectly on their natural
enemies. However, little is known about the effect of herbivore damage on resistant and susceptible plant cultivars and its
effect on their natural enemies. Thus, the aim of this study was to evaluate the attraction of the herbivorous pentatomid
bug Euschistus heros and its egg parasitoid Telenomus podisi to two resistant and one susceptible soybean cultivars with different types of damage (herbivory, herbivory+oviposition,
and oviposition). In a Y-tube olfactometer, the parasitoids were attracted to herbivory and herbivory+oviposition damaged
soybean plants when compared to undamaged soybean plants for the resistant cultivars, but did not show preference for the
susceptible cultivar Silvania in any of the damage treatments. The plant volatiles emitted by oviposition-damaged plants in
the three cultivars did not attract the egg parasitoid. In four-arm-olfactometer bioassays, E. heros females did not show preference for odors of damaged or undamaged soybean plants of the three cultivars studied. The Principal
Response Curves (PRC) analysis showed consistent variability over time in the chemical profile of volatiles between treatments
for the resistant cultivar Dowling. The compounds that most contributed to the divergence between damaged soybean plants compared
to undamaged plants were ( E,E)-α-farnesene, methyl salicylate, ( Z)-3-hexenyl acetate, and ( E)-2-octen-1-ol. 相似文献
18.
The origin of olfactory stimuli involved in the host microhabitat location in Cotesia flavipes, a parasitoid of stem-borer larvae, was investigated in a Y-tube olfactometer. The response of female C. flavipes towards different components of the plant-host complex, consisting of a maize plant infested with two or more larvae of the stem borer Chilo partellus, was tested in dualchoice tests. The concealed lifestyle of the stem-borer larvae did not limit the emission of volatiles attractive to a parasitoid. A major source of the attractive volatiles from the plant-host complex was the stem-borer-injured stem, including the frass produced by the feeding larvae. Moreover, the production of volatiles attractive to a parasitoid was not restricted to the infested stem part but occurs systemically throughout the plant. The uninfested leaves of a stem-borer-infested plant were found to emit volatiles that attract female C. flavipes. We further demonstrate that an exogenous elicitor of this systemic plant response is situated in the regurgitate of a stem-borer larva. When a minor amount of regurgitate is inoculated into the stem of an uninfested plant, the leaves of the treated plant emit volatiles that attract female C. flavipes. 相似文献
19.
Stressed woody plants represent an ephemeral and unpredictable resource for larvae of some species of longhorned beetles (Coleoptera: Cerambycidae) because prime subcortical tissues are rapidly degraded by a guild of xylophagous competitors. Selection favors efficient mechanisms of host and mate location to expedite colonization of hosts by larvae. Based on previous research, we hypothesize that mate location in some species of the subfamily Cerambycinae involves three sequential behavioral stages: (1) both sexes are attracted to larval hosts by plant volatiles; (2) males attract females over shorter distances with pheromones; and (3) males recognize females by contact pheromones in their epicuticular wax layer. We already have evidence of second-stage and third-stage behaviors in three species in this subfamily whose xylophagous larvae feed in hardwood trees: Xylotrechus colonus, Megacyllene caryae, and Neoclytus mucronatus mucronatus. In this report, we evaluate the first behavioral stage of mate location behavior (i.e., independent response of both sexes to host plant volatiles) for the same three species. Supporting our hypothesis, both males and females responded to volatiles emanating from hickory logs in Y-tube olfactometer bioassays. 相似文献
20.
Herbivore-induced plant volatiles are important host finding cues for larval parasitoids, and similarly, insect oviposition
might elicit the release of plant volatiles functioning as host finding cues for egg parasitoids. We hypothesized that egg
parasitoids also might utilize HIPVs of emerging larvae to locate plants with host eggs. We, therefore, assessed the olfactory
response of two egg parasitoids, a generalist, Trichogramma pretiosum (Tricogrammatidae), and a specialist, Telenomus remus (Scelionidae) to HIPVs. We used a Y-tube olfactometer to tests the wasps’ responses to volatiles released by young maize
plants that were treated with regurgitant from caterpillars of the moth Spodoptera frugiperda (Noctuidae) or were directly attacked by the caterpillars. The results show that the generalist egg parasitoid Tr. pretiosum is innately attracted by volatiles from freshly-damaged plants 0–1 and 2–3 h after regurgitant treatment. During this interval,
the volatile blend consisted of green leaf volatiles (GLVs) and a blend of aromatic compounds, mono- and homoterpenes, respectively.
Behavioral assays with synthetic GLVs confirmed their attractiveness to Tr. pretiosum. The generalist learned the more complex volatile blends released 6–7 h after induction, which consisted mainly of sesquiterpenes.
The specialist T. remus on the other hand was attracted only to volatiles emitted from fresh and old damage after associating these volatiles with
oviposition. Taken together, these results strengthen the emerging pattern that egg and larval parasitoids behave in a similar
way in that generalists can respond innately to HIPVs, while specialists seems to rely more on associative learning. 相似文献
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