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1.
Alkaloid tolerance in Manduca sexta and phylogenetically related sphingids (Lepidoptera: Sphingidae) 总被引:2,自引:0,他引:2
Summary. Nicotine tolerance is well known for Manduca sexta. It also occurs in several other sphingids of the subfamilies Macroglossinae and Sphinginae. Only members of the subfamily
Smerinthinae appear to be more susceptible to nicotine intoxication. Phylogenetic trees have been reconstructed from mitochondrial
16S rDNA and nuclear DNA to map nicotine tolerance.?The nicotine binding site of both α-subunits of nicotinic acetylcholine receptors (nAChR) have been amplified and sequenced. No apparent amino acid substitution
can be seen in the putative nicotine binding site of the α-subunits of nAChR from nicotine tolerant and nicotine sensitive sphingids. Thus, a simple target-site modification can be
ruled out as a cause for nicotine tolerance. This finding agrees with feeding experiments: larvae of M. sexta and other sphingids of the Macroglossinae and Sphinginae not only tolerated nicotine, but also many other alkaloids that
affect neuroreceptors other than acetylcholine receptors (nAChR, mAChR).?Only 10 to 20% of nicotine injected into larvae of
nicotine-tolerant taxa could be recovered later as free nicotine, nicotine N-oxide or cotinine, i.e., 80 to 90% must have been converted to polar conjugates or degradation products which are not detectable with the methods
applied. Usually more than 98% of the recoverable alkaloids were found in the faeces. Excretion reached a maximum 6 h after
injection in tolerant taxa. Larvae of Manduca sexta, which were reared on a nicotine-rich diet, showed higher nicotine degradation and faster nicotine elimination than na?ve
larvae. Application of the cytochrome P450 inhibitor SKF 525A (proadifen) reduced the formation of nicotine N-oxide and the rate of alkaloid degradation. Thus, an
inducible detoxification mechanism, coupled with a rapid and inducible excretion, appear to be a strategy in Sphingidae that
helps them to live on host plants rich in otherwise toxic secondary metabolites.
Received 23 March 2001; accepted 4 August 2001. 相似文献
2.
Preferences of six leaf beetle species among qualitatively different leaf age classes of three Salicaceous host species 总被引:2,自引:0,他引:2
Arsi Ikonen 《Chemoecology》2002,12(1):23-28
Summary. As Salicaceous plants produce new leaves for a prolonged period of time, they expose a wide range of differentially aged
leaves to herbivores during the growing season. In this work, I show that young leaves of three Salicaceous species, Populus tremula L., Salix phylicifolia L. and S. pentandra L., contain more nitrogen than conspecific old leaves. In P. tremula and S. pentandra young leaves also contained more low-molecular weight secondary compounds, phenolic glucosides. Leaves of S. phylicifolia did not contain phenolic glucosides in detectable amounts. Furthermore, in P. tremula and S. pentandra young leaves contained less polymeric digestability-reducing phenolics, condensed tannins, than old leaves. In S. phylicifolia, higher concentrations of condensed tannins were found in young leaves. In laboratory feeding trials with six leaf beetle
species, young leaves of the studied plants were invariably preferred in all tested herbivore × host species combinations.
In particular, it is remarkable that three leaf beetle species with known different overall relationships to phenolic glucosides
equally preferred more glucoside-containing young S. pentandra leaves over conspecific old ones. Four beetle species were found to prefer young leaves of S. phylicifolia despite the higher content of condensed tannins in young leaves. These results indicate that the general preference of leaf
beetles for young leaves of Salicaceous plants probably does not primarily result from variable distribution of secondary
compounds. Apparently, the preference for young leaves is fundamentally due to variation in leaf nutritive traits, such as
nitrogen content.
Received 9 February 2001. 相似文献
3.
Summary. In the past decades, several studies have focused on the identification of feeding stimulants for specialists that feed on
solanaceous plants, especially potato (Solanum tuberosum). In the 1950's, a phagostimulant was isolated from potato and tomato for Manduca sexta and characterised as a glycoside. It was suggested that the phagostimulant for M. sexta and Leptinotarsa decemlineata is identical. We tested whether these insects indeed share the same recognition factor. Previous bioassays for L. decemlineata larvae and adults were found to be unsatisfactory, so a new assay system was developed, using starch and wheat flour-based
wafers as a neutral substrate. An aqueous extract of potato foliage that was highly active as a stimulant was fractionated
by reverse phase medium pressure liquid chromatography (MPLC). Both insects were stimulated by a MPLC fraction that eluted
with 25% methanol in water. Further separation of this and the following fraction (35% methanol, stimulatory for the beetle
only) by semi-preparative high performance liquid chromatography (HPLC), using gradients of water and acetonitrile, resulted
in the isolation of two distinct fractions that stimulated feeding by L. decemlineata. None of the HPLC fractions was active for M. sexta. However, fractions of the flash chromatography with less polarity (45–75% methanol) had a stimulatory effect only on M. sexta. Thus, the two insects do not use a common feeding stimulant, and for both at least two compounds of different polarity are
active.
Received 3 July 2000; accepted 24 October 2000 相似文献
4.
Induction of host specificity in larvae of Manduca sexta: chemical dependence controlling host recognition and developmental rate 总被引:2,自引:0,他引:2
Summary. The tobacco hornworm, Manduca sexta L. (Lepidoptera: Sphingidae) is a specialist on Solanaceae. This host specificity is induced as the larva feeds on solanaceous
foliage, so that solanaceous-reared larvae will refuse to feed on other plants. Experiments were designed to determine the
role of dietary constituents on the induction of host specificity and the effects of these on development of M. sexta. Choice assays using leaf discs of cowpea, Vigna sinensis (Fabaceae), were used to monitor the isolation of relevant chemical cues from foliage of potato. An aqueous extract of potato
foliage strongly stimulated feeding. This extract was partitioned with n-butanol under alkaline conditions to obtain a highly active butanol extract. Reversed phase flash chromatography with a water-methanol
gradient gave an active fraction that was used as a supplement for wheat germ-based artificial diet. Larvae reared on this
s-diet became dependent on potato allelochemicals for initiation and continuation of feeding activity. These larvae also developed
faster than larvae reared on the control p-diet, but no effect on adult mass was detected. Further flash chromatography of
the active fraction under alkaline conditions provided a highly active sub-fraction, and semi-preparative HPLC using gradients
of water and acetonitrile resulted in the isolation of a single compound. Bioassays indicated that this compound alone can
account for host recognition by solanaceous-reared larvae. The results suggest that the mechanism of induced host specificity
in M. sexta involves development of dependence on this compound.
Received 21 December 1999; accepted 14 March 2000 相似文献
5.
Jacques M. Pasteels Claudine Theuring Donald M. Windsor Thomas Hartmann 《Chemoecology》2003,13(1):55-62
Summary. Sequestration and processing of pyrrolizidine alkaloids
(PAs) by leaf beetles of the genus Platyphora were investigated. Tracer
experiments with labeled alkaloids were performed with P. eucosma
feeding on Koanophyllon panamense (Asteraceae, tribe Eupatorieae). P.
eucosma catalyzes the same reactions previously demonstrated for P.
boucardi specialized to Prestonia portobellensis (Apocynaceae): (i)
epimerization of rinderine to intermedine; (ii) esterification of
retronecine yielding insect-specific PAs; (iii) efficient transport of
the PAs as free bases into the defensive secretions. P. bella feeding on
Tournefortia cuspidata (Boraginaceae) shows the same sequestration
behavior and ability to synthesize the specific retronecine esters. P.
ligata, a species phylogenetically closely related to the PA adapted
species and clustering in the same clade, but feeding on a host plant
devoid of PAs, feeds easily on PA treated host-plant leaves, but does
not sequester or metabolize PAs. P. kollari a species clustering outside
the PA clade refused to feed on its food-plant leaves painted with PAs.
The results are discussed in relation to host-plant selection of the PA
adapted species and the role of PAs in chemical defense.
Received 20 September 2002; accepted 18 November 2002. 相似文献
6.
Letizia Mattiacci Sara Rudelli Bettina Ambühl Rocca Sem Genini Silvia Dorn 《Chemoecology》2001,11(4):167-173
Summary. Plant responses to herbivory might directly affect the herbivore (“direct” defences) or might benefit the plant by promoting
the effectiveness of natural antagonists of the herbivores (“indirect” defences). Brussels sprouts attacked by Pieris brassicae larvae release volatiles that attract a natural antagonist of the herbivores, the parasitoid Cotesia glomerata, to the damaged plant. In a previous study, we observed that feeding by caterpillars on the lower leaves of the plant triggers
the systemic release of volatiles detectable by the parasitoids from upper leaves of the same plant.?The role of these systemically
induced volatiles as indirect defence and the dynamics of their emission were investigated in wind-tunnel dual choice tests
with C. glomerata. The systemically induced emission of volatiles varied depending on leaf age and on plant age. Systemic induction affected
parasitoid effectiveness, as induced plants could be more easily located by parasitoids than non-induced ones.?The role of
the systemic induction as a direct defence was investigated through behavioural and feeding tests with P. brassicae. In dual choice assays, 1st instar larvae preferred to feed and fed more on systemically induced than on non-induced leaves.
In single choice assays, the leaf area consumed by caterpillars was larger on systemically induced leaves than on non-induced
control leaves. However, caterpillars fed on systemically induced leaves attained the same weight as those feeding on non-induced
controls. In addition, P. brassicae pupae whose larvae were fed on systemically induced leaves had longer developmental times than those of larvae fed on non-induced
leaves. Adult oviposition behavior was not influenced by systemic induction.?We conclude that systemically induced responses
in cabbage might reduce P. brassicae fitness both directly, by affecting their development and feeding behavior and indirectly by making caterpillars and pupae
more vulnerable to attack by carnivores. The occurrence of a possible relationship between direct and indirect defence is
discussed.
Received 24 January 2001; accepted 3 May 2001. 相似文献
7.
J. W. Chapman Trevor Williams Ana M. Martínez Juan Cisneros Primitivo Caballero Ronald D. Cave Dave Goulson 《Behavioral ecology and sociobiology》2000,48(4):321-327
The incidence of cannibalism of larval Spodoptera frugiperda (Lepidoptera: Noctuidae) on maize under field conditions was investigated using field cages. Cannibalism was found to account
for approximately 40% mortality when maize plants were infested with two or four fourth-instar larvae over a 3-day period.
Field trials examined the effect of larval density on the prevalence of natural enemies of S. frugiperda. The abundance of predators (earwigs, staphylinids, other predatory beetles, and Chrysoperla spp.) was significantly greater on maize plants with higher levels of larval feeding damage, while the relationship between
predator abundance and number of S. frugiperda larvae per plant was less clear. As larval damage is probably a more reliable indicator of previous larval density than numbers
collected at an evaluation, this indicates that predation risk will be greater for larvae living in large groups. Parasitism
accounted for 7.1% mortality of larvae in sorghum, and involved six species of Hymenoptera and Tachinidae. There was no effect
of larval density or within-plant distribution on the probability of larval attack by parasitoids. The selective benefits
of cannibalism, in relation to the risk of predation and parasitism, are discussed.
Received: 23 March 2000 / Accepted: 24 June 2000 相似文献
8.
Summary. The ontogeny of pyrrolizidine alkaloid (PA) synthesis
and constraints on defence level during the seedling stage were examined
in the annual Senecio vulgaris and the monocarpic perennial
Senecio jacobaea. In both species, PAs were actively
synthesized from the onset of seedling growth so that juvenile stages
did not go through an undefended stage. Roots are known to be the
exclusive sites where PAs are produced. Root biomass was the single most
important biomass parameter explaining variation in total PAs per
seedling. All correlation coefficients between—relative growth
rate and PA concentration were negative, but none was significant.
However, a significant negative—correlation was found between
shoot to root ratio and PA concentration in S. jacobaeaseedlings, suggesting a dilution effect of the PAs. Earlier studies have
shown that the shoot to root ratio is positively correlated with
relative growth—rate of established S. jacobaea plants.
It is therefore suggested that young S. jacobaea plants
with a high shoot to root ratio and hence a high growth capacity
necessarily have lower PA defence levels than plants with a low
shoot to root ratio.
Received 10 July 2002; accepted 16 November 2002. 相似文献
9.
Claudia Voelckel Tamara Krügel Klaus Gase Nadja Heidrich Nicole M. van Dam Robert Winz Ian T. Baldwin 《Chemoecology》2001,11(3):121-126
10.
Effects of hydrolysable tannins on a herbivorous insect: fate of individual tannins in insect digestive tract 总被引:2,自引:0,他引:2
Summary. We investigated the effects of four chemically characterised galloylglucoses (GGs, a subgroup of hydrolysable tannins) and
their hydrolysis product, gallic acid (GA), on consumption and performance of larvae of the autumnal moth Epirrita autumnata. Larvae were fed with birch (Betula pubescens) leaves that had been painted individually with each of the compounds at two levels, 5 and 20 mg/g. In addition, we investigated
the fates of the leaf-painted GGs and GA in the E. autumnata digestive tract by comparing phenolics in leaves consumed and in faeces. In general, GGs reduced leaf consumption by E. autumnata during the second and fourth instars, although there was high compound- and instar-specific variation. However, GGs did not
affect the leaf consumption rates by the most voracious fifth instar larvae. This resulted in approximately the same loss
of total biomass by the experimental tree, regardless of the nature and level of GGs enriched to its foliage. The characteristic
fate of hydrolysable tannins, i.e. hydrolysis, was evidenced in the larval digestive tract for three of the four leaf-painted
GGs. In addition to hydrolysis, the almost total absence of GGs in larval faeces was presumably related to the oxidation of
GGs. The dose-dependent excretion percentage of ingested GA showed that it's faecal content should not be used, although it
commonly is, to calculate the level of GG hydrolysis. Moreover, by comparing the non-uniform appearance of faecal tetragalloylglucoses,
whether ingested as such or hydrolysed from pentagalloylglucose, we concluded that a major part of oxidation of GGs occurs
before their hydrolysis in the digestive tract of E. autumnata. Criticism against the common use of tannic acid, a heterogeneous mixture of GA and GGs, in ecological studies is presented.
Received 15 May 2002; accepted 16 July 2002 相似文献
11.
Summary. Sequestration of plant toxins in herbivores is often
correlated with aposematic coloration and gregarious behaviour. Larvae
of Pieris brassicae show these conspicuous morphological and behavioural
characteristics and were thus suggested to sequester glucosinolates that
are characteristic secondary metabolites of their host plants. P. rapaeare camouflaged and solitary, and are thus not expected to sequester. To
test this hypothesis and to check the repeatabi-lity of a study that did
report the presence of the glucosinolate sinigrin in P. brassicae,
larvae were reared on three species of Brassicaceae (Sinapis alba,
Brassica nigra and Barbarea stricta), and different leaf and insect
samples were taken for glucosinolate analysis. The major host plant
glucosinolates could only be found in traces or not at all in larval
haemolymph, bled or starved larvae, faeces or pupae of both species or
P. brassicae regurgitant. Haemolymph of both Pieris spp. was not
rejected by the ant Myrmica rubra in dual-choice assays; the regurgitant
of P. brassicae was rejected. This suggests the presence of compounds
other than glucosinolates that might be sequestered in or produced by P.
brassicae only. In faeces of both Pieris spp. a compound which yielded
4-hydroxybenzylcyanide (HBC) upon incubation with sulfatase was detected
in high concentrations when larvae had been reared on S. alba. This
compound may be derived from hydrolysis of sinalbin, the main
glucosinolate of that plant. The unidentified HBC progenitor was
apparently not sequestered in the two Pieris spp., and was not detected
in faeces of larvae reared on B. nigra or B. stricta.
Received 18 July 2002; accepted 11 September 2002. 相似文献
12.
Summary. We investigated the hypothesis that aggregation signals produced by male webbing clothes moths (WCM), Tineola bisselliella (Hum.) (Lepidoptera: Tineidae), and close-range male attractant signals produced by females have a pheromonal basis, at least
in part. Gas chromatographic-electroantennographic detection (GC-EAD) and GC-mass spectrometric analyses of bioactive methanolic
extracts of male WCM disclosed three candidate pheromone components: hexadecanoic acid methyl ester (16:Ester), (Z)-9-hexadecenoic acid methyl ester (Z9—16:Ester), and octadecanoic acid methyl ester (18:Ester). In bioassay experiments in a large Plexiglas™ arena, a blend of
synthetic 16:Ester plus Z9—16:Ester was attractive to male and virgin (but not mated) female WCM; the 18:Ester was inactive.
GC-EAD analyses of pheromone gland extracts from female WCM revealed (E,Z)-2,13-octadecadienal (E2Z13—18:Ald) and (E,Z)-2,13-octadecadienol (E2Z13—18:OH) as candidate sex pheromone components. In arena bioassay experiments, 1—5 female equivalents of synthetic E2Z13—18:Ald (0.2 ng) and E2Z13—18:OH (0.1 ng) were more attractive to male WCM than were two virgin female WCM. We anticipate that the combination of
aggregation and sex pheromones, male-produced sonic aggregation signals, and habitat-derived semiochemicals will be highly
effective in attracting male and female WCM to commercial traps.
Received 12 January 2001; accepted 8 June 2001. 相似文献
13.
Susanna Andersson 《Chemoecology》2003,13(1):1-11
Summary. For butterflies to be efficient foragers, they need to
be able to recognize rewarding flowers. Flower signals such as colours
and scents assist this recognition process. For plant species to attract
and keep butterflies as pollinators, species-specific floral signals are
crucial. The aim of this study is to investigate foraging responses to
floral scents in three temperate butterfly species, Inachis io L.
(Nymphalidae), Aglais urticae L. (Nymphalidae), and
Gonepteryx rhamni L. (Pieridae), in behavioural choice
bioassays. The butterflies were allowed to choose bet-ween flower models
varying in scent and colour (mauve or green). Flowers or vegetative
parts from the plants Centaurea scabiosa L. (Asteraceae),
Cirsium arvense (L.) (Asteraceae), Knautia arvensis (L.)
(Dipsacaceae), Buddleja davidii Franchet (Loganicaeae), Origanum vulgareL. (Lamiaceae), Achillea millefolium L. (Asteraceae), and
Philadelphus coronarius L. (Hydrangiaceae) were used as scent
sources. All visits to the models — those that included probing and
those that did not — were counted, as was the duration of these
behaviours. Both flower-naive and flower-experienced (conditioned to
sugar-water rewards, the colour mauve, and specific floral scents)
butterflies were tested for their preference for floral versus
vegetative scents, and to floral scent versus colour. The butterflies
were also tested for their ability to switch floral scent preferences in
response to rewards. Flower-naive butterflies demonstrated a preference
for the floral scent of the butterfly-favourable plants C.
arvense and K. arvensis over the floral scent of the non-favourable
plants Achillea millefolium (Asteraceae), and Philadelphus
coronarius cv. (Hydrangiaceae). Most of the butterflies that were
conditioned to floral scents of either C. arvense, K. arvensis,
or B. davidii readily switched theirfloral scent preferences to
the one most recently associated with reward, thus demonstrating that
floral scent constancy is a result from learning. These findings suggest
that these butterflies use floral scent as an important cue signal to
initially identify and subsequently recognize and distinguish among
rewarding plants.
Received 2 September 2001; accepted 9 September 2002. 相似文献
14.
Summary. The ability to perceive and respond to phytochemicals that reliably indicate poor suitability of a potential host plant confers
a selective advantage to ovipositing female swallowtail butterflies. Papilio glaucus females are generalists that nonetheless do not oviposit on red bay (Persea borbonia: Lauraceae). Red bay is toxic to P. glaucus neonates but is commonly found in habitats alongside their principal host plant, Magnolia virginiana, in central Florida. The hypothesis that deterrent compounds present in the leaves of red bay mediate its rejection by P. glaucus was evaluated in our study. Florida populations of P. glaucus did not oviposit on host leaves sprayed with the methanol extract of red bay foliage, although they accepted solvent-treated
and untreated tulip tree leaves in 3 choice bioassays. Additionally, tulip tree leaves sprayed with methanolic extracts of
red bay also deterred oviposition by P. glaucus females from Ohio, Kentucky and Pennsylvania, although these populations do
not naturally encounter red bay. Clearly, deterrent compounds found within this non-host are the basis of its rejection by
populations of P. glaucus and such recognition is fundamental to the species, not just a reflection of local adaptations.
Received 2 April 1999; accepted 11 June 1999. 相似文献
15.
Tamara Krügel Michelle Lim Klaus Gase Rayko Halitschke Ian T. Baldwin 《Chemoecology》2002,12(4):177-183
Summary. Research into the genetic basis of the ecological sophistication of plants is hampered by the availability of transformable
systems with a wealth of well-described ecological interactions. We present an Agrobacterium-mediated transformation system for the model ecological expression system, Nicotiana attenuata, a native tobacco that occupies the post-fire niche in the Great Basin Desert of North America. We describe a transformation
vector and a transformation procedure that differs from the standard cultivated tobacco transformation protocols in its use
of selectable markers, explants, media and cultivation conditions. We illustrate its utility in the transformations with genes
coding for key enzymes in the oxylipin cascade (lipoxygenase, allene oxide synthase, hydroperoxide lyase) in antisense orientations
and present high-throughput screens useful for the detection of altered phenotypes for the oxylipin cascade (green leaf volatiles
and jasmonic acid after wounding).
Received 14 March 2002; accepted 10 May 2002 相似文献
16.
17.
Summary. The among-leaves allocation of DIBOA, a hydroxamic acid associated with plant resistance, in the shoot of rye (Secale cereale) was evaluated over the vegetative development of the plant. The appropriateness of using the concentration of secondary
metabolites, DIBOA in this case, as the parameter to evaluate defense allocation in plants is discussed. Both biological and
statistical arguments are put forward to suggest that allocation of chemical defenses should refer to absolute content and
not to concentration. Results showed that leaf age was significantly linked to leaf concentration of DIBOA, young leaves having
higher concentrations. In contrast, leaf content of DIBOA, our proposed currency of allocation, was not significantly higher
in younger leaves. Furthermore, a regression analysis showed that the DIBOA content of leaves was better explained by the
leaf relative biomass (proportion of shoot biomass) than by leaf biomass itself. It is suggested that, rather than leaf age,
leaf relative biomass is the major factor determining DIBOA allocation in rye shoots. It is proposed that studies addressing
within-plant defense allocation should use chemical defense content as the currency, emphasizing the major factors driving
this process and its underlying mechanisms. Likewise, it is proposed that studies aiming at characterizing optimal patterns
of plant defense should use chemical defense concentration as the currency, and be accompanied by evaluations of the actual
resistance against herbivores of the plant parts analyzed, together with the effect on plant fitness.
Received 19 February 1999; accepted 28 April 1999. 相似文献
18.
Little has been done to compare the relative importance of various mechanisms through which prey assess the potential risk
from natural enemies. We used predator-naive spider mites (Tetranychus urticae, Tetranychidae) to (1) compare the responses of prey to chemical cues from enemy and non-enemy species and (2) investigate
the source of these cues. In the laboratory, we observed the distribution of T. urticae in response to cues from nine mite species, including (1) predators of spider mites, (2) predators/parasites of other animals,
and (3) fungivores/pollen-feeders. When given a choice over 24 h, spider mites foraged and oviposited in fewer numbers on
leaf discs that were previously exposed to predatory or parasitic mites (including species incapable of attacking spider mites)
than on clean leaf discs (unexposed to mites). Interestingly, previous exposure of leaf arenas to fungivores and pollen-feeders
had no significant effect on spider mite distribution. We then observed the response of T. urticae to cues from two species of predator that had been reared on a diet of either spider mites or pollen. T. urticae showed stronger avoidance of leaf discs that were previously exposed to spider-mite-fed predators than of discs exposed to
pollen-fed predators. Nevertheless, for one predator species (Amblyseius andersoni), T. urticae still preferred to forage and oviposit on clean (unexposed) discs than on discs exposed to pollen-fed predators. Protein-derived
metabolic wastes of predatory or parasitic mites may provide a general cue about potential predation risk for T. urticae. However, T. urticae also avoided areas exposed to pollen-fed predators, suggesting there may be other sources of enemy recognition by the spider
mites. We discuss the ecological and evolutionary mechanisms that may influence the scope of information through which animals
assess predation risk.
Received: 11 January 1999 / Received in revised form: 25 October 1999 / Accepted: 20 November 1999 相似文献
19.
Jacques M. Pasteels Arnaud Termonia Donald M. Windsor Ludger Witte Claudine Theuring Thomas Hartmann 《Chemoecology》2001,11(3):113-120
Summary. Field collected exocrine defensive secretions of nine neotropical Platyphora species were analyzed for the presence of plant acquired pyrrolizidine alkaloids (PAs) and pentacyclic triterpene saponins.
All species secrete saponins. In addition, five species feeding on Tournefortia (Boraginaceae), Koanophyllon (Asteraceae, tribe Eupatorieae) and Prestonia (Apocynaceae) were shown to sequester PAs of the lycopsamine type, which are characteristic for species of the three plant
families. The PA sequestering species commonly store intermedine, lycopsamine and their O3′-acetyl or propionyl esters as well as O7- and O9-hydroxyisovaleryl esters of retronecine. The latter as well as the O3′-acyl esters were not found in the beetles’ host plants, suggesting the ability of the beetles to esterify plant derived retronecine
and intermedine or its stereoisomers. Despite the conformity of the beetles’ PA patterns, considerable inconsistencies exist
regarding the PA patterns of the respective host plants. One host plant was devoid of PAs, while another contained only simple
necines. Since the previous history of the field collected beetles was unknown this discrepancy remains obscure. In contrast
to the Palearctic chrysomeline leaf beetles, e.g. some Oreina species which ingest and store PAs as their non-toxic N-oxides, Platyphora leaf beetles absorb and store PAs as the toxic free base (tertiary PA), but apparently avoid to accumulate PAs in the haemolymph.
This suggests that Chrysolina and Platyphora leaf beetles developed different lines of adaptations in their parallel evolution of PA mediated chemical defense.
Received 30 November 2000; accepted 5 February 2001 相似文献
20.
Summary. Sensitivities to methyl eugenol of three sibling species in the Bactrocera dorsalis complex were compared. The degree of species sensitivity to methyl eugenol, i.e. B. dorsalis > B. papayae > B. carambolae (in decreasing order), was concomitant with the species age-related response to methyl eugenol as previously reported. The
ability to consume methyl eugenol by the three sibling species showed similar trend - the average ME consumption per male
was 0.70 ml for B. dorsalis, 0.58 ml B. papayae and 0.18 μl B. carambolae. Results obtained were discussed in relation to area-wide control of fruit fly.
Received 21 April 2002; accepted 9 July 2002 相似文献