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1.
The influence of different concentrations of ozone under different light intensities on young trees of European beech (Fagus sylvatica L.) is studied. Young beeches were exposed continuously for 5 months in fumigation chambers, located outdoors, with 131±30/μg/m3O3, and for 2 months in fumigation chambers, located in air‐conditioned greenhoouses, with 100±10, 200±20 and 300±30/μg/m3O3, respectively. The observed symptoms point towards an increased xeromorphism in beech leaves, positively influenced by high light intensities. Ozone‐induced water stress may be the cause of xeromorphic tissue changes. On the ultrastructural level chloroplasts have become senescent. 相似文献
2.
Nadia Scascighini Letizia Mattiacci Marco D’Alessandro Alan Hern Anja Sybille Rott Silvia Dorn 《Chemoecology》2005,15(2):97-104
Summary. It is well known that feeding by Pieris brassicae caterpillars on cabbage leaves triggers the release of volatiles that attract natural antagonists such as the parasitoid Cotesia glomerata. The temporal dynamics in the emissions of parasitoid attracting volatiles has never been elucidated in this system. In a time course experiment, caterpillar infested leaves attracted the parasitoid within one hour after infestation. At such an early stage of infestation, as much as fifty percent of the parasitoids flew towards the infested plant in a wind tunnel bioassay, while only five percent flew towards the non-infested control plant. Three hours after infestation and later, the response to the volatiles from the infested plant reached its maximum and then continued at a constantly high level for the remaining 14 hours of the experiment. Chemical analyses of volatiles collected from infested leaves at short time intervals during the first 24 hours identified a total of ten compounds, comprising green leaf volatiles, terpenoids, and a nitrile. Significant increase of emission within the first 5 hours following initial herbivory was detected for (Z)-3-hexen-1-ol, (Z)-3-hexen-1-yl acetate, cineole and benzylcyanide. Subsequently, a coupled bioassay-chemical analysis procedure was developed allowing for testing and analyzing the same sample for future identification of the bioactive compounds. This was achieved by using stir bar sorptive extraction for the analysis of solvent extracts of caterpillar-damaged leaves. 相似文献
3.
Summary Feeding by the homopteranPsylla pyricola on leaves of pear trees induces the production of volatile compounds, such as (E,E)--farnesene and methyl-salicylate, as well as the production of polyphenols. The inference on induction is based on GC-MS and HPLC chromatograms from the same samples ofPsylla infested leaves, leaves from the same pear tree beforePsylla infestation and uninfested leaves from other pear trees.Psylla infestation greatly enhanced the production of volatiles ((E,E)--farnesene, methyl-salicylate and others) and triggered the production of new polyphenols, characterized by much longer retention times.However, the responses to infestation depend critically on leaf age (defined by leaf distance to apex). With respect to the leaf volatiles it appears that infested, old leaves produce fewer compounds and lower amounts of the volatiles than infested, young leaves. Moreover, there seem to be differences in pattern. Relative to (E,E)--farnesene, methyl-salicylate was found in much lower amounts in heavily infested, old leaves. With respect to polyphenols it was found that infested old leaves collected in August have polyphenols with the same retention times, but more or less equal amounts as uninfested young leaves collected in May. This shows thatPsylla infestation causes the induced response mostly in young leaves.The induced leaf volatiles may act as synomones to heteropteran bugs. As shown elsewhere,Anthocoris nemoralis responds significantly to (E,E)--farnesene and methyl-salicylate when offered in pure form against clean air in a Y-tube olfactometer. The effect of polyphenols on the performance ofP. pyricola is not yet known. Hence, a role in direct defence is still to be investigated. 相似文献
4.
Paolo Lo Bue Stefano Colazza Lisa D. Forster Jocelyn G. Millar Robert F. Luck 《Chemoecology》2004,14(3-4):151-156
Summary. Metaphycus sp. nr.
flavus (Encyrtidae: Hymenoptera)
is a parasitoid species collected from the Mediterranean
region which lays its eggs in the immature stages of several
economically important soft scale insects (Hemiptera:
Coccidae), including brown soft scale, Coccus hesperidum
L. (= host insect). Preliminary tests suggested that the parasitoid
is most successful in producing offspring when it
oviposits in the younger stages of brown soft scale. In
Y-olfactometer bioassays measuring wasp choices and residence
times, naïve parasitoids were significantly more
attracted to yucca leaves infested with 26, 27, or 28 d-old
scale than to uninfested leaves, whereas leaves with older
(29-30 d-old) scale were no more attractive than uninfested
leaves. Parasitoids also spent significantly more time in the
arm with yucca leaves infested with 26 d-old scale than in
the arm with uninfested leaves. These results are consistent
with observations of the parasitoids reproductive success on
scale of different ages, whereby older scale are more likely
to encapsulate the developing eggs of M.
sp. nr. flavusfemales than are younger scale. Further bioassays determined
that yucca leaves that had been infested with 26 d-old
scale but from which the scale had been removed were as
attractive as infested leaves. In contrast, infested yucca
leaves from which scale had been removed and the leaves
subsequently washed with distilled water were less attractive
than infested leaves. Furthermore, the wash water
containing scale residues was attractive to female wasps. In
total, these results suggest that Metaphycussp. nr. flavus
females utilize volatile, water soluble compounds produced
by brown soft scale as cues to locate suitable hosts. 相似文献
5.
Summary. Ponderosa pine, Pinus ponderosa Laws. (Pinaceae), forests in Arizona have suffered from a nine-year period of drought and bark beetle, Ips lecontei Swaine (Coleoptera: Scolytidae), outbreaks. Abiotic and biotic stress in ponderosa pine results in the induced synthesis
of certain monoterpenes that may in turn affect bark beetle behavior and survival. In this study, we investigate whether induced
monoterpene production could result in a different monoterpene composition that remains stored in the needles or the trunk
resin of the tree. Needle and resin samples in addition to trunk cores were collected from ponderosa pines at three locations
in Arizona. Ungulate browsing induced a significant increase in limonene (P=0.010) and in chemodiversity (P=0.009), a measure
of the evenness of distribution among the monoterpenes present in needles. We compared the level of ‘stress’ of the trees
by measuring the thickness of annual rings in living trees and those that were killed by bark beetles. Where drought occurred,
the spacing of annual rings from the last 10 years of trees killed by bark beetles was significantly smaller (P=0.020) compared
to living trees. There was no difference in the monoterpene composition between the core sections of closest spacing of annual
rings (stressed years) compared to the sections of widest spacing, which indicates that monoterpenes are distributed evenly
throughout the extended resin system. In the area where the degree of drought was less overall, none of the individual monoterpenes
present in the resin was related to bark beetle killed trees. However, about half the living pines had resin in which one
of the major monoterpenes (α-pinene, Δ3-carene, and limonene) was absent, and these trees had a lower monoterpene chemodiversity compared to trees killed by bark
beetles. Trees with these three major monoterpenes, corresponding to the average relative proportion in living pines at that
location, may sustain higher selection and colonization by bark beetles. 相似文献
6.
Summary. Feeding by belowground herbivores may induce systemic changes in shoot defence levels that affect the performance of above
ground herbivores and higher trophic levels. In this paper two wild Brassica species, B. nigra and B. oleracea were experimentally infested with 10 larvae of the cabbage root fly, Delia radicum. Plant dry masses and glucosinolate levels in shoots, main roots, and fine roots were determined at 3, 7, 12 and 14 days
after infestation and compared to those of control plants.
The systemic response in the leaves differed between plant species. In B. nigra shoot glucosinolate levels in D. radicum infested plants steadily increased with time until they were almost twice those of controls 14 days after infestation. B. oleracea plants infested with D. radicum did not show significant changes in shoot glucosinolate levels within 14 days, which may be due to the unexpected poorer
performance of D. radicum on this species.
Both plant species showed a local increase in indole glucosinolates in the main roots, which are the preferred feeding site
of D. radicum larvae. B. oleracea plants however showed a stronger (1.9 – 4.7 times) increase in indole glucosinolate levels than B. nigra (1.5 – 2.6 times). The increase in indole glucosinolates in B. nigra main roots, was counterbalanced by a significant decrease in aromatic glucosinolate levels. These differences in local responses
to D. radicum feeding between the two species may have contributed to the slower growth rates of the larvae on B. oleracea. D. radicum feeding did not result in altered glucosinolate levels in the fine roots in either plant species. The differences in glucosinolate
induction patterns between the summer annual B. nigra and the perennial B. oleracea are discussed in the light of their different life histories. 相似文献
7.
Summary. Host selection in tree-killing bark beetles
(Coleoptera: Scolytidae) is mediated by a complex of semiochemical
cues. Using gas chromatographic-electroantennographic
detection (GC-EAD) and GC-mass spectrometric
analyses, we conducted a comparative study of the electrophysiological
responses of four species of tree-killing bark
beetles, the Douglas-fir beetle, Dendroctonus pseudotsugae,
Hopkins, the mountain pine beetle, D. ponderosae Hopkins,
the spruce beetle, D. rufipennis Kirby, and the western balsam
bark beetle, Dryocoetes confusus Swaine, to volatiles
captured by aeration of 1) bole and foliage of four sympatric
species of conifers, Douglas-fir, Pseudotsuga menziesii
(Mirb.) Franco, lodgepole pine, Pinus contorta var. latifolia
Engelm., interior spruce, Picea engelmannii x glauca, and
interior fir, Abies lasiocarpa x bifolia, and 2) con- and
heterospecific beetles at three stages of attack. We identified
13 monoterpenes in the conifers and nine compounds in the
volatiles of beetles that elicited antennal responses. There
was no qualitative difference in the terpene constitution of
the four species of conifers and very little difference across
beetle species in their antennal response to compounds from
conifers or beetles. The lack of species-specific major or
minor components in conifers suggests that beetles would
need to detect differences in the ratios of different compounds
in conifers to discriminate among them. Attraction to
hosts and avoidance of nonhost conifers may be accentuated
by perception of compounds emitted by con- and heterospecific
beetles, respectively. The 22 compounds identified
are candidate semiochemicals with potential behavioural
roles in host location and discrimination. 相似文献
8.
Bridging the gap between ecophysiological and genetic knowledge to assess the adaptive potential of European beech 总被引:1,自引:0,他引:1
K. Kramer J. Buiteveld M. Forstreuter T. Geburek S. Leonardi P. Menozzi F. Povillon M.J. Schelhaas E. Teissier du Cros G.G. Vendramin D.C. van der Werf 《Ecological modelling》2008,216(3-4):333-353
In this study we aimed to combine knowledge of the ecophysiology and genetics of European beech to assess the potential of this species to adapt to environmental change. Therefore, we performed field and experimental studies on the genetic and ecophysiological functioning of beech. This information was integrated through a coupled genetic–ecophysiological model for individual trees that was parameterized with information derived from our own studies or from the literature. Using the model, we evaluated the adaptive response of beech stands in two ways: firstly, through sensitivity analyses (of initial genetic diversity, pollen dispersal distance, heritability of selected phenotypic traits, and forest management, representing disturbances) and secondly, through the evaluation of the responses of phenotypic traits and their genetic diversity to four management regimes applied to 10 study plots distributed over Western Europe. The model results indicate that the interval between recruitment events strongly affects the rate of adaptive response, because selection is most severe during the early stages of forest development. Forest management regimes largely determine recruitment intervals and thereby the potential for adaptive responses. Forest management regimes also determine the number of mother trees that contribute to the next generation and thereby the genetic variation that is maintained. Consequently, undisturbed forests maintain the largest amount of genetic variation, as recruitment intervals approach the longevity of trees and many mother trees contribute to the next generation. However, undisturbed forests have the slowest adaptive response, for the same reasons.Gene flow through pollen dispersal may compensate for the loss in genetic diversity brought about by selection. The sensitivity analysis showed that the total genetic diversity of a 2 ha stand is not affected by gene flow if the pollen distance distribution is varied from highly left-skewed to almost flat. However, a stand with a prevailing short-distance gene flow has a more pronounced spatial genetic structure than stands with equal short- and long-distance gene flows. The build-up of a spatial genetic structure is also strongly determined by the recruitment interval. Overall, the modelling results indicate that European beech has high adaptive potential to environmental change if recruitment intervals are short and many mother trees contribute to the next generation.The findings have two implications for modelling studies on the impacts of climate change on forests. Firstly: it cannot be taken for granted that parameter values remain constant over a time horizon of even a few generations – this is particularly important for threshold values subject to strong selection, like budburst, frost hardiness, drought tolerance, as used in species area models. Secondly: forest management should be taken into account in future assessments, as management affects the rate of adaptive response and thereby the response on trees and forests to environmental change, and because few forests are unmanaged. We conclude that a coupled ecophysiological and quantitative genetic tree model is a useful tool for such studies. 相似文献
9.
Summary. The pollen beetle, Meligethes aeneus, is an important pest of oilseed rape, Brassica napus. Larvae of this species feed only in the buds and flowers of Brassicaceae. One important natural enemy of this beetle is
the parasitoid Phradis morionellus that attacks larvae in buds and flowers and also feeds on the flowers. The preferences for odours of non-infested and infested
rape were tested for both starved and fed parasitoids in Y-tube olfactometer experiments. The volatile blend released from
pollen beetle-infested and non-infested flowering rape and from pollen beetle larvae was identified and quantified. Gas chromatography-electroantennodetection
analyses were performed with female P. morionellus. Parasitoids in both treatment groups preferred infested rape, but the proportion of responding female P. morionellus was significantly lower for the group that was starved. Six of the 20 volatiles identified were released at higher rates
from infested rape than from non-infested. None of these compounds was found in pollen beetle larvae headspace. P. morionellus antennae detected both major and minor components in the volatile blend. The volatiles released at a significantly higher
rate from infested rape and detected by P. morionellus antennae were (Z)-3-hexenylacetate, (Z)-3-hexenol, 3-butenyl isothiocyanate and (E,E)-α-farnesene. 相似文献
10.
Variation in composition of predator-attracting allelochemicals emitted by herbivore-infested plants: Relative influence of plant and herbivore 总被引:9,自引:0,他引:9
Summary During foraging, natural enemies of herbivores may employ volatile allelochemicals that originate from an interaction of the herbivore and its host plant. The composition of allelochemical blends emitted by herbivore-infested plants is known to be affected by both the herbivore and the plant. Our chemical data add new evidence to the recent notion that the plants are more important than the herbivore in affecting the composition of the volatile blends. Blends emitted by apple leaves infested with spider mites of 2 different species,T. urticae andP. ulmi, differed less in composition (principally quantitative differences for some compounds) than blends emitted by leaves of two apple cultivars infested by the same spider-mite species,T. urticae (many quantitative and a few qualitative differences). Comparison between three plant species — apple, cucumber and Lima bean — reveals even larger differences between volatile blends emitted upon spider-mite damage (many quantitative differences and several qualitative differences). 相似文献
11.
The effect of beech bark disease on tree growth was tracked using paired resistant and susceptible American beech trees in
two locations in Maine. Within each site, the paired trees were chosen in close proximity and with similar morphological characteristics
(e.g. stem diameter and crown class) to minimize environment effects in subsequent analysis. A Kalman filter approach was
employed to analyse the yearly time-dependent mean differences between paired susceptible and resistant tree-ring widths using
simple structural time series models in state space form. On one site, under the influence of a moderate maritime climate,
stand dynamics is hypothesized to account for the 34 year difference in onset of decline of trees in codominant, versus those
in the intermediate crown classes. The harsher winter conditions associated with the second, more northerly site and known
to limit the insect component of the disease complex, are hypothesized to be more of a factor in the close (six year) difference
in decline onset between the two crown classes on this site. Some strengths and cautions in the Kalman filter approach are
discussed in relation to the analysis of time-dependent trends in tree-ring series. 相似文献
12.
Summary. Using Porapak Q traps, we collected the bark volatiles of six angiosperm trees native to British Columbia: black cottonwood,
Populus trichocarpa Torr. & A. Gray (Salicaceae), trembling aspen, P. tremuloides Michx. (Salicaceae), paper birch, Betula papyrifera Marsh. (Betulaceae), bigleaf maple, Acer macrophyllum Pursh (Aceraceae), red alder, Alnus rubra Bong. (Betulaceae), and Sitka alder, A. viridis ssp. sinuata (Regel) á. L?ve & D. L?ve (Betulaceae). Utilising coupled gas chromatographic-electroantennographic detection analysis, the
captured volatiles were assayed for antennal responses in five species of coniferophagous bark beetles (Coleoptera: Scolytidae),
sympatric with most or all of the angiosperm trees: the Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, the mountain pine beetle, D. ponderosae Hopkins, the spruce beetle, D. rufipennis (Kirby), the western balsam bark beetle, Dryocoetes confusus Swaine, and the pine engraver, Ips pini (Say). The identities of 25 antennally-active compounds were determined by coupled gas chromatographic-mass spectroscopic
analysis, and co-chromatographic comparisons with authentic chemicals. The compounds identified were: hexanal, (E)-2-hexenal, (Z)-3-hexen-1-ol, 1-hexanol, heptanal, α-pinene, frontalin, benzaldehyde, β-pinene, 2-hydroxycyclohexanone, 3-carene, limonene,
β-phellandrene, benzyl alcohol, (E)-ocimene, salicylaldehyde, conophthorin, guaiacol, nonanal, methyl salicylate, 4-allylanisole, decanal, thymol methyl ether,
(E)-nerolidol, and dendrolasin. A number of these compounds are known semiochemicals that are active in the behaviour of other
organisms, including bark beetles, suggesting a high degree of semiochemical parsimony. Antennally-active compounds ranged
from seven in A. viridis to 17 in P. trichocarpa. The fewest number of compounds (9) were detected by I. pini and the largest number (24) were detected by D. pseudotsugae. Six compounds excited the antennae of all five species of bark beetles. The large number of antennally-active compounds
detected in common by numerous bark beetles and present in common in numerous nonhost trees supports the hypothesis of olfaction-based
recognition and avoidance of nonhost angiosperm trees during the process of host selection by coniferophagous bark beetles.
Received 13 December 1999; accepted 14 March 2000 相似文献
13.
John H. Borden Ian M. Wilson Regine Gries Leslie J. Chong Harold D. Pierce Jr. Gerhard Gries 《Chemoecology》1998,8(2):69-75
Summary. Coupled gas chromatographic-electroantennographic detection (GC-EAD) analysis of the Porapak Q-captured volatiles from the
bark of trembling aspen, Populus tremuloides Michx., revealed four compounds that consistently elicited antennal responses by mountain pine beetles (MPBs), Dendroctonus ponderosae Hopkins. One of these, 1-hexanol, disrupted the capture of MPBs in multiple-funnel traps baited with the aggregation pheromones
trans-verbenol and exo-brevicomin and the host kairomone myrcene, a blend of semiochemicals that mediates the secondary attraction response in which
beetles mass attack and kill living pines. The other three EAD-active aspen bark volatiles, benzyl alcohol, benzaldehyde and
nonanal, were inactive alone, but in binary and ternary combinations contributed to a disruptive effect in an additive and
redundant manner when all four aspen bark volatiles were tested in all possible binary and ternary blends. The best ternary
blend and the quarternary blend achieved ≥ 80% disruption. The quarternary blend enhanced the disruptive effect of the antiaggregation
pheromone verbenone in traps, raising the disruptive effect to 98%, and also enhanced the inhibition of attack on attractant-baited
lodgepole pines. This is the first demonstration of specific compounds from the bark of angiosperm trees that disrupt the
secondary attraction response of sympatric coniferophagous bark beetles. The results support the hypothesis that such bark
beetles are adapted to recognize and avoid non-host angiosperm trees by responding to a broad spectrum of volatiles that can
act in various blends with equal effect.
Received 27 October 1997; accepted 20 February 1998. 相似文献
14.
The impact of a parasitic infestation may be influenced by nutritional state, in both individuals and colonies. This study
examined the interaction between pollen storage and the effects of an infestation by the mite, Varroa jacobsoni Oudemans, in colonies of the honey bee, Apis mellifera L. We manipulated the pollen storage and mite infestation levels of colonies, and measured pollen foraging and brood rearing.
Increased pollen stores decreased both the number of pollen foragers and pollen load size, while initially at least foragers
from colonies with moderate infestations carried smaller pollen loads than those from lightly infested colonies. Over the
course of the experiment, all colonies significantly increased pollen-foraging rates and pollen consumption, which was presumably
a seasonal effect. Lightly infested colonies exhibited a larger increase in pollen forager number than moderately infested
colonies, suggesting that more intense mite infestations compromised forager recruitment. Brood production was not affected
by the addition of pollen, but moderately infested colonies were rearing significantly less brood by the end of the experiment
than lightly infested colonies. Furthermore, the efficiency with which colonies converted pollen to brood decreased as the
pollen storage level decreased and the infestation level increased. The results of this study may indicate that honey bee
colonies adaptively alter brood-production efficiency in response to parasitic infestations and seasonal changes.
Received: 3 May 1999 / Received in revised form: 14 September 1999 / Accepted: 25 September 1999 相似文献
15.
Jorma Tahvanainen Riitta Julkunen-Tiitto Matti Rousi Paul B. Reichardt 《Chemoecology》1991,2(1):49-54
Summary A sample of one-year-old seedlings of European white birch (Betula pendula) was analyzed to determine the content of sugars, phenolics and terpenoid compounds. Two vertical segments of each seedling were analyzed separately. The number of resin droplets, which correlates strongly and negatively with feeding by the mountain hare, was also counted on the bark of experimental seedlings. The variation in the palatability of birch seedlings to mountain hare was determined primarily by the most abundant terpenoid, papyriferic acid. On the other hand, the resistance to hare feeding at the seedling bases, which are frequently attacked by voles, appeared to be dependent on other components, apparently phenolic substances. Sugars did not affect the resistance of the tested seedlings. The variation among experimental seedlings was much greater for secondary substances, especially terpenoid compounds, than for sugars. It is suggested that this high variation in protective compounds may be an adaptive trait selected for by the feeding of generalist herbivores. 相似文献
16.
David Wainhouse Tristram Wyatt Alun Phillips David R. Kelly Mehrdad Barghian Paul Beech-Garwood David Cross Rex S. Howell 《Chemoecology》1991,2(1):55-63
Summary Adults of the predatory beetleRhizophagus grandis are strongly attracted to both adult and larval frass of its specific prey,Dendroctonus micans, in walking bioassays. Spruce bark and resin are relatively unattractive. Solvent extracts of larval frass that were attractive toR. grandis adults in a flight wind tunnel contained a mixture of monoterpenes of host plant origin. A synthetic mixture of these monoterpenes, (+)—-pinene, (–)—-pinene, -phellandrene,dl limonene and 3-carene, was responsible for 70–80% of the activity of the most attractive extract. We suggest that a blend of monoterpenes in frass acts as a kairomone forR. grandis but that attraction to monoterpenes is only the first of a sequence of behavioural responses that ensures successful host location and identification. 相似文献
17.
Juan Camilo Marín Loaiza Carlos L. Céspedes Till Beuerle Claudine Theuring Thomas Hartmann 《Chemoecology》2007,17(2):109-115
Summary. The occurrence of pyrrolizidine alkaloids (PAs) in Pittocaulon (ex Senecio) praecox (Asteraceae) a species endemic to Mexico was established. The aboveground plant organs contain the 1,2-saturated monoester
7-angeloyl-dihydroxyheliotridane together with a small proportion of its 9-angeloyl isomer as major alkaloid. The monoesters
are accompanied by the macrocyclic otonecine derivative senkirkine. Roots contain only related macrocyclic PAs with senecionine,
senkirkine and platyphylline as major components; monoesters are absent. The broom-like succulent stems of P. praecox are infested by the scale insect Ceroplastes albolineatus conspicuously visible by its huge wax cover. All life-history stages, i.e. females, eggs, first instar nymphs (crawlers)
and the wax cover were found associated with PAs. The measured PA concentrations clearly indicate sequestration. The highest
PA concentrations (mg / g dry weight) reached are: mature females, 0.44; eggs, 0.58; crawlers, 0.37; wax cover, 0.08. The
host plant as well as in the infesting scale insect contain the PAs exclusively as free bases. As a phloem-feeder C. albolineatus must acquire the PAs with the ingested phloem sap. This appears plausible since in Senecio species PA are transmitted and circulated through the phloem path. It is suggested that PAs may protect particularly the
crawlers as the most endangered stage in the life-cycle of the scale insect. 相似文献
18.
Summary. Qualitative and quantitative differences among pear cultivars were found
in constitutive and Cacopsylla-induced volatiles, depending on
experimental treatment of the trees (i.e., uninfested and partly or
completely infested by psyllids). Blend differences were also found
between pear cultivars and wild-type pear, alder and hawthorn–the
latter trees are frequently present in pear orchard
hedgerows. ?Interesting differences were found in the presence of methyl
salicylate and (E,E)-α-farnesene, two compounds previously found to
mediate attraction of predatory bugs towards psyllid-infested pear
trees. Methyl salicylate is expressed constitutively and is induced
systemically by infestation in the whole plant of all four cultivars.
(E,E)-α-farnesene on the other hand showed also systemic induction in
Bartlett, NY10355 and Beurré Hardy, but in partially infested Conference
trees it was induced locally, only in herbivore-damaged leaves. No
methyl salicylate or (E,E)-α-farnesene were identified in honeydew. In
field collected headspace samples of alder leaves infested by aphids and
leaf beetles we found methyl salicylate but no (E,E)-α-farnesene,
whereas in uninfested hawthorn neither were identified. Insight in the
variability of damage-related pear volatiles will have important
implications for integrated pest management in the field.
Received 27 August 2002; accepted 28 November 2002
R1D="
Correspondence to: Petru Scutareanu, e-mail:scuterea@science.uva.nl 相似文献
19.
We studied the role of echolocation and other sensory cues in two small frugivorous New World leaf-nosed bats (Phyllostomidae: Artibeus watsoni and Vampyressa pusilla) feeding on different types of fig fruit. To test which cues the bats need to find these fruit, we conducted behavioral experiments in a flight cage with ripe and similar-sized figs where we selectively excluded vision, olfaction, and echolocation cues from the bats. In another series of experiments, we tested the discrimination abilities of the bats and presented sets of fruits that differed in ripeness (ripe, unripe), size (small, large), and quality (intact(infested with caterpillars). We monitored the bats' foraging and echolocation behavior simultaneously. In flight, both bat species continuously emitted short (<2 ms), multi-harmonic, and steep frequency-modulated (FM) calls of high frequencies, large bandwidth, and very low amplitude. Foraging behavior of bats was composed of two distinct stages: search or orienting flight followed by approach behavior consisting of exploration flights, multiple approaches of a selected fruit, and final acquisition of ripe figs in flight or in a brief landing. Both bat species continuously emitted echolocation calls. Structure and pattern of signals changed predictably when the bats switched from search or orienting calls to approach calls. We did not record a terminal phase before final acquisition of a fruit, as it is typical for aerial insectivorous bats prior to capture. Both bat species selected ripe over unripe fruit and non-infested over infested fruit. Artibeus watsoni preferred larger over smaller fruit. We conclude from our experiments, that the bats used a combination of odor-guided detection together with echolocation for localization in order to find ripe fruit and to discriminate among them. 相似文献
20.
New repellent semiochemicals for three species of
<Emphasis Type="Italic">Dendroctonus</Emphasis> (Coleoptera: Scolytidae) 总被引:1,自引:0,他引:1
Summary. Nine compounds identified from captured
volatiles of the Douglas-fir beetle, Dendroctonus pseudotsugae,
the mountain pine beetle, D. ponderosae, and the
spruce beetle, D. rufipennis, that elicited antennal responses
in males and females of one or more of these species were
tested in the field to determine behavioural activity.
1-Octen-3-ol, found in the volatiles of females of all three
species decreased the response of male and female coastal
and male interior D. pseudotsugae and both sexes of D. ponderosae
to their aggregation pheromones. Acetophenone,
identified in the volatiles of females of all three species,
significantly decreased the response of interior female
D. pseudotsugae. trans-Verbenol, a potent aggregation
pheromone of D. ponderosae, decreased the response of both
sexes of D. pseudotsugae, while 3-methyl-2-cyclohexen-1-
one (MCH), the antiaggregation pheromone of D. pseudotsugae
and D. rufipennis decreased the response of both sexes
of D. ponderosae. While it has been demonstrated that semiochemical
mediated interspecific communication occurs
among bark beetles infesting the same host, this study
demonstrates that beetles can perceive signals emitted by
heterospecifics attacking nonhosts and can potentially use
them to avoid attacking the wrong species of conifer. 相似文献