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1.
Summary. In earlier investigations on host plant discrimination of leaf beetles glucosinolates were described as feeding stimulants
for the Brassicaceae specialist Phaedon cochleariae F. (Coleoptera: Chrysomelidae). However, since these findings could not be confirmed in later studies offering 2-propenylglucosinolate
in concentrations corresponding to those detected in host plant leaf material, the identification of feeding stimulants of
this leaf beetle species remained unclear. In order to investigate which compounds of the host plant Sinapis alba (Brassicaceae) are involved in feeding stimulation, leaf extracts of different polarities were tested in bioassays with adults
of P. cochleariae. Number of feeding beetles and net consumption rates were highest on pea leaves painted with methanol extracts of S. alba, whereas weak feeding responses were also detectable for hexane extracts. In subsequent bioassay-guided fractionations of
methanol extracts with semi-preparative high performance liquid chromatography, two distinct fractions, one containing glucosinolates
and another containing flavonoids, were found to stimulate beetles to feed to variable degrees. Other collected fractions
had zero activity. The combination of both active fractions evoked significantly higher consumption rates and stimulated more
beetles to feed than fractions tested individually. At least one compound of each fraction, among these the main glucosinolate
of S. alba, 4-hydroxybenzylglucosinolate, act additively. Effects of two different naturally-occurring ratios of glucosinolates and
flavonoids on the strength of feeding responses were investigated by use of extracts of two sets of host plants differently
exposed to radiation. One set was outdoors-exposed, whereas the second set was kept in the greenhouse. However, the feeding
behaviour of P. cochleariae was not affected by the significantly different relative compositions of both compound classes in the host material. In conclusion,
mustard leaf beetles need a combination of distinct plant metabolites acting in concert for feeding stimulation, whereby the
mere presence of these stimulants, but probably not the ratio of involved compounds, determines their feeding response. 相似文献
2.
Summary The attraction of Old World leaf beetles in the genusAulacophora to kairomones and parakairomones which are effective lures for New WorldDiabrotica andAcalymma were investigated. Beetles captured on sticky traps baited with single and multicomponent lures were no different from the control traps for two species ofAulacophora. Yellow colored traps and squash blossoms are attractive toAulacophora beetles which detect sub-microgram quantities of cucurbitacins on silica gel. Leaf feeding behavior and flight activity data are correlated with varietal preference of threeAulacophora species. The common response byDiabrotica andAulacophora to cucurbitacins reinforces the two groups' coevolutionary association with the Cucurbitaceae. The apparent lack of a common response toCucurbita blossom volatiles suggests recent evolutionary pathways are substantially different for these two groups of beetles. 相似文献
3.
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
4.
Thomas Eisner Jeffrey Conner James E. Carrel John P. McCormick Amy J. Slagle Carl Gans James C. O'Reilly 《Chemoecology》1990,1(2):57-62
Summary Frogs(Rana pipiens) fed on blister beetles (Meloidae) or cantharidin, retain cantharidin systemically. After cessation of feeding, they void the compound relatively quickly. Systemic cantharidin does not protect frogs against ectoparasitic feeding by leeches(Hirudo medicinalis) or predation by snakes(Nerodia sipedon). As suggested by our data, and from reports in the early literature, ingestion of cantharidin-containing frogs can pose a health threat to humans.Paper no. 95 of the seriesDefense Mechanisms of Arthropods; no. 94 is LaMunyon & Eisner, Psyche (in press) 相似文献
5.
Alexandra Bottcher Jorge Paulo Zolin Flávia Nogueira-de-Sá José Roberto Trigo 《Chemoecology》2009,19(1):63-66
The most frequently investigated defence mechanism among larvae of tortoise beetles is protection by faecal shields, which
generally present chemicals that are directly sequestered and/or modified from larval host-plants. In the present work we
investigate the tortoise beetle Chelymorpha reimoseri that feeds on the leaves of Ipomoea carnea fistulosa (Convolvulaceae), seeking for the importance of this mechanism to their larvae. We show that 4th instar larvae suffer low
predation regardless of the presence of shields in field and laboratory bioassays with ants and chicks. Chloroform extract
from larvae without shields provided high protection against predation as shown in bioassays in the field, as well as against
chicks, suggesting that C. reimoseri does not rely on the shield for protection. The aqueous extract of the shields did not show activity in such bioassays. The
compounds responsible for this protection have yet to be identified, and it remains an open question as to whether they are
sequestered from the host plant or de novo biosynthesized. This is the first record of chemical defence in cassidine beetles
without the need for faecal shields. These findings indicate that more attention should be paid to chemicals present in the
tissues of larvae and/or adults of tortoise beetles; the protective compounds sequestered from host plants or de novo biosynthesized
can provide an alternative or complementary strategy against predation in these insects. 相似文献
6.
Martine Rowell-Rahier Ludger Witte Adelheid Ehmke Thomas Hartmann Jacques M. Pasteels 《Chemoecology》1991,2(1):41-48
Summary
Oreina cacaliae andO. speciosissima (Coleoptera, Chrysomelidae) sequester in their elytral and pronotal defensive secretions pyrrolizidine alkaloids (PAs) as Noxides (PA N-oxides). The PA N-oxide patterns found in the beetles and their host plants were evaluated qualitatively and quantitatively by capillary gas chromatography/mass spectrometry (GC-MS). Of the three host plantsAdenostyles alliariae (Asteraceae) is the exclusive source for PA N-oxide sequestration in the defensive secretions of the beetles. With the exception of O-acetylseneciphylline the N-oxides of all PAs ofA. alliariae, i.e. senecionine, seneciphylline, spartioidine, integerrimine, platyphylline and neoplatyphylline were identified in the secretion. PA N-oxides typical ofSenecio fuchsii (Asteraceae) were detected in the bodies of the beetles but not in their secretion. No PAs were found in the leaves of the third host plant,Petasites paradoxus (Asteraceae). The results suggest the existence of two distinctive storage compartments for PA N-oxides in the beetle: (1) the defensive secretion, containing specifically PA N-oxides acquired fromA. alliariae; (2) the body of the beetle, sequestering additionally but less selectively PA N-oxides from other sources,e.g. S. fuchsii or monocrotaline N-oxide fed in the laboratory. The concentration of PA N-oxides in the defensive secretion is in the range of 0.1 to 0.3 mol/1, which is more than 2.5 orders of magnitude higher than that found in the body of the beetle. No significant differences exist in the ability of the two species of beetles to sequester PA N-oxides fromA. alliariae, althoughO. speciosissima, but notO. cacaliae, produces autogenous cardenolides. A negative correlation seems to exist between the concentrations of plant-derived PA N-oxides andde novo synthesized cardenolides in the defensive secretion ofO. speciosissima. 相似文献
7.
The curculionid beetle Naupactus
bipes (Germar, 1824) (Coleoptera: Curculionidae: Brachycerinae) has shown feeding preference for leaves of Piper gaudichaudianum, demonstrating an unexpected specificity for an insect considered to be a generalist. The leaves of P. gaudichaudianum contain the prenylated chromenes gaudichaudianic acid (4, major compound) and its methyl ester (5) in addition to a chromene (3) lacking one prenyl residue. In addition to 4, roots contain the chromone methyl ester (1) and methyl taboganate (2, major compound). Feeding on roots, larvae of N. bipes sequester exclusively the root-specific compounds 1 and 2. Adult beetles sequester the leaf-specific chromenes 3 and 4, but were found to also contain compounds 1 and 2 that are absent in leaves. Therefore, it is suggested that 1 and 2 are sequestered by larvae and can be found in the body of adult insects after long-term storage. In addition, 3 and 4, the major compounds in leaves were found to be associated with the eggs. 相似文献
8.
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
9.
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
10.
Anne Lyytinen Leena Lindström Johanna Mappes Riitta Julkunen–Tiitto Sergey R. Fasulati Kari Tiilikkala 《Chemoecology》2007,17(1):51-56
Summary. Many studies investigating effects of plant chemicals on herbivore performance have reported contradictory results, perhaps
because of possible interaction between different chemicals. Also, a herbivore’s performance is not necessarily consistent
with its food or oviposition preference. Our aim was to investigate simultaneously antibiosis (larval growth and survival)
and antixenosis (oviposition and feeding preferences) responses in herbivore to three plant chemicals, of which one is expected
to have positive and two are expected to have negative effects. Antibiosis was measured by correlating the nitrogen and glycoalkaloid
levels in host plants to the survival and adult size of Leptinotarsa decemlineata, by rearing larvae on whole plants of three potato varieties. Although host plants differed in their glycoalkaloid levels,
survival rate and adult body size did not differ among beetles reared on different potato varieties. This suggests that beetles
are quite robust for differences in both foliar α-chaconine and foliar α-solanine content. However, differences in antixenosis
were found although they could not be directly predicted from the leaf chemistry. Females preferred to lay their eggs on the
variety with high α-solanine content (Nevsky) towards which males showed a tendency to feeding preference. Overall, our results
confirm that beetles are well adapted to the chemical defences of potato plants as potato varieties did not significantly
affect beetle performance, but differences in oviposition preference may still result in major differences in the amount of
damage inflicted on plants in the fields. 相似文献
11.
Summary. Oviposition site selection of herbivorous insects depends primarily on host plant presence which is essential for offspring
survival. However, parasitoids can exploit host plant cues for host location. In this study, we hypothesised that herbivores
can solve this dilemma by ovipositing within high plant diversity. A diverse plant species composition might represent an
‘infochemical shelter’, as a potentially complex volatile blend can negatively affect the host location ability of parasitoids.
We examined this exemplarily for the egg-laying response of the generalist leaf beetle, Galeruca tanaceti, in relation to (1) host plant availability and (2) plant species diversity in the field. Further, we investigated the effect
of odours from mixed plant species compositions on (3) leaf beetle oviposition site selection and on (4) the orientation of
its specialised egg parasitoid, Oomyzus galerucivorus. In the field, egg clutch occurrence was positively related to the presence and quantity of two major host plants, Achillea millefolium (yarrow) and Centaurea jacea, and to the number of herbaceous plant species. In two-choice bioassays, female beetles oviposited more frequently on sites
surrounded by an odour blend from a diverse plant species composition (including yarrow) than on sites with a pure grass odour
blend. In the presence of yarrow odour and an odour blend from a diverse plant mixture (including yarrow) no difference in
the oviposition response was recorded. Experienced parasitoid females were attracted to yarrow odours, but showed no response
when yarrow odours were offered simultaneously with odours of a non-host plant. In conclusion, it could be shown in laboratory
bioassays that the parasitoid responds only to pure host plant odours but not to complex odour blends. In contrast, the herbivore
prefers to oviposit within diverse vegetation in the field and in the laboratory. However, the laboratory results also point
to a priority of host plant availability over the selection of a potential ‘infochemical shelter’ for oviposition due to high
plant diversity. 相似文献
12.
Leaf surface chemicals stimulating oviposition byPieris rapae (Lepidoptera: Pieridae) on cabbage 总被引:3,自引:0,他引:3
Summary The chemical stimulation of oviposition byPieris rapae on cabbage was investigated by leaf washing and extraction. Isolation of the stimulant by various chromatographic techniques was monitored by a bioassay using Sieva bean as a surrogate host plant. Cold water, chloroform, or chloroform followed by cold water washes failed to release the stimulant from leaf surfaces. Boiling water or chloroform followed by methanol was required. The most active stimulatory compound was identified as 3-indolylmethyl glucosinolate (glucobrassicin). Other glucosinolates were identified as sinigrin, which was only slightly active, and glucoiberin, which was completely inactive as a stimulant. The significance of the selective response ofP. rapae andP. brassicae to different glucosinolates and the implications of the binding of polar allelochemicals to leaf surfaces is discussed with respect to host utilization and perception mechanisms of pierids. 相似文献
13.
加拿大一枝黄花和小飞蓬叶浸提液对大豆幼苗生长的复合化感效应 总被引:1,自引:0,他引:1
加拿大一枝黄花(Solidago canadensis)和小飞蓬(Conyza canadensis)常共同入侵至同一农田生态系统。探究了两者对大豆幼苗生长的复合化感作用。加拿大一枝黄花叶浸提液显著抑制大豆幼苗地上生物量。而小飞蓬叶浸提液也明显抑制大豆幼苗地上生物量(未达到显著水平)。与对照处理相比,两者复合叶浸提液处理未显著影响大豆幼苗地上生物量。两者复合叶浸提液处理下大豆幼苗地上生物量显著大于加拿大一枝黄花叶浸提液单一处理,同时也大于小飞蓬叶浸提液单一处理(未达到显著水平)。两者叶浸提液单一处理均明显降低大豆幼苗株高(未达到显著水平)。与对照处理相比,两者复合叶浸提液处理未显著影响大豆幼苗株高。两者复合叶浸提液处理下大豆幼苗株高明显大于两者叶浸提液单一处理(未达到显著水平)。因此,两者叶浸提液对大豆幼苗的生长均具有一定程度的抑制效应,且加拿大一枝黄花叶浸提液对大豆幼苗产生的化感作用(尤其是地上生物量)明显大于小飞蓬。两者复合化感作用明显低于两者单一化感作用,尤其是两者对大豆幼苗地上生物量的复合化感作用显著低于加拿大一枝黄花的单一化感作用。所以,化感效应可能在两者共同入侵(即两者复合作用)进程中所起的贡献低于在两者单一入侵进程中所起的作用。 相似文献
14.
Competition with flies promotes communal breeding in the burying beetle,Nicrophorus tomentosus 总被引:3,自引:0,他引:3
Michelle Pellissier Scott 《Behavioral ecology and sociobiology》1994,34(5):367-373
Communal breeding through nest-sharing may benefit cooperating individuals indirectly, in increased inclusive fitness, or directly, when environmental constraints reduce the fitness of solitary breeders. Burying beetles provide extensive parental care and can breed either in pairs or in larger groups of unrelated males and females. Parentage of communally-reared broods is usually shared but is skewed in favor of the individuals of each sex that provide longer care. Females provide care longer than males, and two females are more likely to remain together in the brood chamber than two males are. Flies and other burying beetles are the major competitors for carcasses and this study suggests that it is competition with flies that promotes communal breeding inNicrophorus tomentosus On medium-size carcasses (35–40 g) the presence or absence of oviposition by flies had a significant effect on the size of the brood reared, and on large carcasses (55–60 g) the number of beetles present, two or four, had a significant effect on brood size. On both medium and large carcasses, pairs rearing broods on flyblown carcasses had fewer young than pairs on clean carcasses or foursomes on flyblown carcasses. There was a strong trend for an interaction effect between number of beetles and competition with flies (Table 1). Duration of parental care was not affected by competition with flies except for that of the first male to depart, which provided care longer on flyblown carcasses (Table 2). Pairs and foursomes were equally able to defend the carcass and brood from conspecific intruders and from larger intrudingNicrophorus orbicollis (Table 3). 相似文献
15.
Thomas Eisner Kevin D. McCormick Makoto Sakaino Maria Eisner Scott R. Smedley Daniel J. Aneshansley Mark Deyrup Ronald L. Myers Jerrold Meinwald 《Chemoecology》1990,1(1):30-37
Summary Analyses of leaf extracts ofDicerandra frutescens, a highly aromatic mint plant from central Florida listed as an endangered species, revealed presence of 12 closely related monoterpenes. The principal of these, (+)—trans-pulegol, is a new natural product, the synthesis of which is described. The terpenes are produced in glandular capsules that release their contents upon injury of the leaf. Data from bioassays with ants and cockroaches indicate that the terpenes serve for defense against insects.Dicerandra does, however, have a leaf-eating enemy, the caterpillar of a pyralid moth,Pyrausta panopealis. The discovery of a new natural product from an endangered species raises questions about the chemical implications of species extinction. 相似文献
16.
Liisa Huttunen Pekka Niemelä Riitta Julkunen-Tiitto Susanne Heiska Riitta Tegelberg Matti Rousi Seppo Kellomäki 《Chemoecology》2008,18(2):85-98
Summary. We examined the effects of defoliation con-currently with elevated temperature and CO2 on some chemical and morphological characteristics in the leaves of silver birch seedlings (Betula pendula). We also analyzed the consequent changes in the palatability of leaves for adult blue alder leaf beetles (Agelastica alni). Under the different climatic treatments, the seedlings were subjected to three fertilizer treatments (0 kg, 130 kg and
270 kg N ha−1) and defoliation treatments (0%, 25% and 50% of the total leaf area). In each climatic treatment, fertilization increased
the nitrogen content in the leaves, but decreased total concentrations of soluble phenolics, detected by high-performance
liquid chromatography (HPLC), and insoluble condensed tannins. Defoliation, both independently and in combination with elevated
temperature and CO2, decreased the concentrations of the phenolics. Compared to the intact controls, the leaves of the defoliated seedlings were
smaller and tougher. Under elevated temperature, the beetles consumed a smaller amount of the leaves of plants subjected to
the high fertilization, while under ambient climatic conditions, fertilization increased the feeding. The total leaf consumption
was higher under the ambient climatic conditions than under elevated temperature, elevated CO2 or the combination of elevated temperature and CO2. 相似文献
17.
Summary. Larvae of the turnip sawfly, Athalia rosae L. (Hymenoptera: Tenthredinidae), sequester glucosinolates of their host plants, namely members of the Brassicaceae family,
in their haemolymph. Therefore, they need to circumvent myrosinase activities of the plant tissue which normally hydrolyse
the glucosinolates after plant damage. Effects of varying levels of glucosinolates and myrosinases on the performance of A. rosae were investigated using homozygous lines of Brassica juncea (L.) with either (1) low glucosinolate (lowGS) and low myrosinase (lowMR), (2) high glucosinolate (highGS) and high myrosinase (highMR), or (3) high glucosinolate (highGS) and low myrosinase (lowMR) levels. To insure that the given quantities remained as constant as possible, newly hatched larvae were enclosed on the
second-youngest leaf of a plant, and were offered a new plant of comparable physiological age (6-leaf-stage) every day. The
performance of A. rosae was little affected by leaf quality. Body masses of eonymphs and adults were on average lowest on the highGS/highMR-line, but these differences were rarely significant. The pupal developmental times of females and males were longest on
the highGS/lowMR-line in only one of two replicate experiments. All other performance traits (developmental times of larvae, egg numbers,
adult longevity) were not significantly different. Glucosinolates, sequestered by the larvae, are carried through the pupal
stage. The glucosinolate concentration measured in adult insects reflected the level of the host plant line, without showing
any obvious costs for sequestration. Obviously, A. rosae is highly tolerant to variation in the glucosinolate-myrosinase system of its host.
In addition, induced changes of glucosinolate concentrations and myrosinase activities caused by 24 h-feeding of groups of
three small larvae were analysed in the second-youngest leaves. In contrast to the patterns most herbivores evoke on Brassicaceae,
namely an increase of both glucosinolate concentration and myrosinase activity, we detected a significant decrease of both
traits in all three lines where the respective trait was originally high in the plants. Although glucosinolate levels dropped in the highGS lines about 50%, these still contained higher concentrations than the lowGS line. Whereas the activity of soluble myrosinases remained highest in the highMR line, even after a decrease to almost 30% due to feeding, the levels of insoluble myrosinases converged after feeding in
lowMR and highMR lines. Levels of the signalling molecule salicylic acid slightly decreased on average after feeding, whereas jasmonic acid
was below the detection threshold in almost all samples. The concentration of several molecules varies strongly in plant tissue
with age and can change due to induction by herbivore feeding. Therefore, if performance of an insect species is measured
on plants with specific traits, the variability in these traits needs to be carefully controlled in experiments. 相似文献
18.
Summary. Late instar larvae of the monarch butterfly (Danaus plexippus L., Lepidoptera: Nymphalidae) deactivate the latex defense of milkweeds by chewing a furrow in the leaf midrib or petiole. The larva then feeds beyond the cut where latex outflow is minimal. If a larva does encounter latex exudate during feeding, it often returns to its initial cut to damage the midrib or petiole more extensively before resuming feeding. We used this response to latex as an assay for testing what cue triggers vein cutting. A sticky solution of polyethylene glycol and a mixture of cardenolides both were ineffective; drops applied to the mouthparts of feeding monarchs failed to elicit renewed vein cutting. Activity resided instead within a methanol extract of the supernatant obtained from centrifuged latex of the milkweed, Asclepias curassavica L. (Asclepiadaceae). Treatment with proteinase K did not eliminate activity documenting that the active compound is unlikely to be proteinaceous. Our results indicate that latex adhesiveness and low polarity cardenolides are relatively unimportant releasers of vein cutting. We propose that milkweeds contain noncardenolide stimulants of vein cutting; these compounds presumably serve a defensive role for milkweeds. Over 50 species of insects are known to employ vein-cutting before feeding on plants with canal-borne exudates; most of these species are dietary specialists like the monarch. Our behavioral assay provides a novel approach for identifying ecologically-significant compounds in the exudates of their diverse host plants. 相似文献
19.
Eisner T Schroeder FC Snyder N Grant JB Aneshansley DJ Utterback D Meinwald J Eisner M 《Chemoecology》2008,18(2):109-119
Summary. Beetles of the family Lycidae have long been known to be chemically protected. We present evidence that North American species
of the lycid genera Calopteron and Lycus are rejected by thrushes, wolf spiders, and orb-weaving spiders, and that they contain a systemic compound that could account,
at least in part, for this unacceptability. This compound, a novel acetylenic acid that we named lycidic acid, proved actively
deterrent in feeding tests with wolf spiders and coccinellid beetles. Species of Lycuscommonly figure as models of mimetic associations. Among their mimics are species of the cerambycid beetle genus Elytroleptus, remarkable because they prey upon the model lycids. We postulated that by doing so Elytroleptus might incorporate the lycidic acid from their prey for their own defense. However, judging from analytical data, the beetles
practice no such sequestration, explaining why they remain relatively palatable (in tests with wolf spiders) even after having
fed on lycids. Chemical analyses also showed the lycids to contain pyrazines, such as were already known from other Lycidae,
potent odorants that could serve in an aposematic capacity to forestall predatory attacks.
David Utterback: Deceased 相似文献
20.
Sandra Steiger Klaus Peschke Josef K. Müller 《Behavioral ecology and sociobiology》2008,62(7):1053-1060
Nestmate recognition in eusocial insects has received a lot of attention in the last decades. Recognition in subsocial species,
in contrast, has been ignored almost completely and consequently, and little is known about proximate mechanisms of recognition
in subsocial systems. We studied one subsocial species, the biparental brood caring burying beetle Nicrophorus vespilloides, an interesting model organism for studies of recognition because of its ability to discriminate between breeding partners
and conspecific competitors. Recognition appears to be based on a chemical cue closely linked to the breeding status of individuals.
Breeding and non-breeding beetles consistently differ in their relative proportions of polyunsaturated cuticular hydrocarbons.
To investigate the function of these polyenes in the burying beetles’ recognition system, we quantified their concentration
on the cuticle during the early state of a breeding attempt and tested the response of breeding beetles in corresponding behavioural
experiments. We observed a rapid increase in the proportion of polyunsaturated hydrocarbons of both males and females after
they were provided with a carcass suitable for reproduction. Furthermore, we found that the relative amount of polyenes on
an individual’s surface was closely correlated with its chance of being accepted as breeding partner. Our results support
the idea that polyunsaturated hydrocarbons are involved in breeding partner recognition in N. vespilloides, functioning as a signal that conveys information about the individual’s breeding status. Breeding females have greater amount
of polyenes than breeding males, and females ingest more carrion during the first days on the carcass, which supports our
hypothesis that precursors for the respective polyenes are derived from ingested carrion. 相似文献