| foraging in nature by larvae of manduca sexta-influenced by an endogenous oscillation. | foraging by larvae of the moth manduca sexta was studied in the field on the native host plant datura wrightii. continuous observation of individuals revealed that larvae moved very little, but fed for approximately one third of the time, independent of temperature or photoperiod, although the larger ones fed for the longest times. they were indiscriminate with respect to the part of plant fed upon, and analysis of feeding bouts and interbouts indicated that the pattern of feeding was not strong ... | 2000 | 10742532 |
| absorption and storage of phosphorus by larval manduca sexta. | the role of phosphorus (p) in numerous important biological structures, coupled with the observation that p-content of many insect foods is disproportionately low, suggests that p may be a critical nutrient for growing insects - however, the few studies examining the effects of dietary p on insect performance have generally found only weak relationships. this mismatch may be reconciled by understanding the physiological mechanisms by which insects handle p. here we describe p processing by larva ... | 2002 | 12770083 |
| costs of glandular trichomes in datura wrightii: a three-year study. | models accounting for genetic variation for resistance to herbivores within plant populations often postulate a balance between the costs of that resistance and its benefits. the production of glandular trichomes by datura wrightii was shown to be costly in a previous one-year study because plants producing glandular trichomes (sticky plants), a factor conferring resistance to some insect herbivores, also produced 45% fewer seeds than plants producing nonglandular trichomes (velvety plants) when ... | 2003 | 12778549 |
| electroantennographic and behavioral responses of the sphinx moth manduca sexta to host plant headspace volatiles. | coupled gas chromatography with electroantennographic detection (gc-ead) using antennae of adult female manduca sexta was employed to screen for olfactory stimulants present in headspace collections from four species of larval host plants belonging to two families: solanaceae--lycopersicon esculentum (tomato), capiscum annuum (bell pepper), and datura wrightii; and martyniaceae--pronboscideaparviflora. headspace volatiles were collected from undamaged foliage of potted, living plants. gc-ead rev ... | 2003 | 12956509 |
| dietary phosphorus affects the growth of larval manduca sexta. | although phosphorus has long been considered an important factor in the growth of diverse biota such as bacteria, algae, and zooplankton, insect nutrition has classically focused on dietary protein and energy content. however, research in elemental stoichiometry has suggested that primary producer biomass has similar n:p ratios in aquatic and terrestrial systems, and phosphorus-rich herbivores in freshwater systems frequently face phosphorus-limited nutritional conditions. therefore, herbivorous ... | 2004 | 14981659 |
| floral co(2) emission may indicate food abundance to nectar-feeding moths. | as part of a study of the roles of the sensory subsystem devoted to co(2) in the nectar-feeding moth manduca sexta, we investigated co(2) release and nectar secretion by flowers of datura wrightii, a preferred hostplant of manduca. datura flowers open at dusk and wilt by the following noon. during the first hours after dusk, when manduca feeds, the flowers produce considerable amounts of nectar and emit levels of co(2) that should be detectable by moths nearby. by midnight, however, both nectar ... | 2004 | 15257387 |
| floral co2 reveals flower profitability to moths. | the hawkmoth manduca sexta (lepidoptera: sphingidae), an experimentally favorable lepidopteran that is highly sensitive to carbon dioxide (co2), feeds on the nectar of a range of flowering plants, such as datura wrightii (solanaceae). newly opened datura flowers give off dramatically elevated levels of co2 and offer ample nectar. thus, floral co2 emission could indicate food-source profitability. this study documents that foraging manduca moths prefer surrogate flowers that emit high levels of c ... | 2004 | 15303329 |
| biological activity of acyl glucose esters from datura wrightii glandular trichomes against three native insect herbivores. | datura wrightii is dimorphic for leaf trichome type in southern california. "sticky" plants produce glandular trichomes that secrete acylsugars, whereas velvety plants produce nonglandular trichomes. glandular trichomes confer resistance to some potential insect herbivores and are associated with reduced feeding in the field by two native coleopteran herbivores: the tobacco flea beetle, epitrix hirtipennis, and a weevil, trichobaris compacta. in contrast, another native beetle, lema daturaphila, ... | 2005 | 16222787 |
| positive selection for single amino acid change promotes substrate discrimination of a plant volatile-producing enzyme. | we used a combined evolutionary and experimental approach to better understand enzyme functional divergence within the sabath gene family of methyltransferases (mts). these enzymes catalyze the formation of a variety of secondary metabolites in plants, many of which are volatiles that contribute to floral scent and plant defense such as methyl salicylate and methyl jasmonate. a phylogenetic analysis of functionally characterized members of this family showed that salicylic acid methyltransferase ... | 2007 | 17374877 |
| context- and scale-dependent effects of floral co2 on nectar foraging by manduca sexta. | typically, animal pollinators are attracted to flowers by sensory stimuli in the form of pigments, volatiles, and cuticular substances (hairs, waxes) derived from plant secondary metabolism. few studies have addressed the extent to which primary plant metabolites, such as respiratory carbon dioxide (co(2)), may function as pollinator attractants. night-blooming flowers of datura wrightii show transient emissions of up to 200 ppm above-ambient co(2) at anthesis, when nectar rewards are richest. t ... | 2008 | 18212123 |
| behavioral consequences of innate preferences and olfactory learning in hawkmoth-flower interactions. | spatiotemporal variability in floral resources can have ecological and evolutionary consequences for both plants and the pollinators on which they depend. seldom, however, can patterns of flower abundance and visitation in the field be linked with the behavioral mechanisms that allow floral visitors to persist when a preferred resource is scarce. to explore these mechanisms better, we examined factors controlling floral preference in the hawkmoth manduca sexta in the semiarid grassland of arizon ... | 2008 | 18305169 |
| characterization and coding of behaviorally significant odor mixtures. | for animals to execute odor-driven behaviors, the olfactory system must process complex odor signals and maintain stimulus identity in the face of constantly changing odor intensities [1-5]. surprisingly, how the olfactory system maintains identity of complex odors is unclear [6-10]. we took advantage of the plant-pollinator relationship between the sacred datura (datura wrightii) and the moth manduca sexta[11, 12] to determine how olfactory networks in this insect's brain represent odor mixture ... | 2009 | 19230669 |
| reproductive biology of datura wrightii: the benefits of a herbivorous pollinator. | a deeper understanding of mutualism can be reached by studying systems with measurable costs and benefits. most studies of this type focus on an unusual class of obligate, species-specific pollination mutualisms. the interaction between datura wrightii (solanaceae) and the hawkmoth manduca sexta offers similar advantages but greater generality. adult moths both nectar at and deposit eggs on the same plant; larvae are herbivorous. the antagonistic component of this interaction has been well studi ... | 2009 | 19287014 |
| the breath of a flower: co(2) adds another channel-and then some-to plant-pollinator interactions. | in this article i comment on our findings that floral carbon dioxide (co(2)) can be used by manduca sexta hawkmoths in a scale- and context-dependent fashion. we firstly found, in wind tunnel assays, that diffusing floral co(2) is used as long-distance cue (e.g., meters). moths track co(2) plumes up-wind in the same manner they track floral odors. nevertheless, co(2) did not appear to function as a local stimulus for flower probing, evidencing a scale-dependent role in nectar foraging. these res ... | 2008 | 19513201 |
| floral trait associations in hawkmoth-specialized and mixed pollination systems: datura wrightii and agave spp. in the sonoran desert. | variation in floral traits including odor, color and morphology, demonstrate the selective pressures imposed by specific pollinator taxa, such as insects and birds. in southern arizona, manduca sexta (sphingidae) hawkmoths are associated with datura wrightii (solanaceae) at both the larval (herbivore) and adult (nectar feeding) stages. however during most of the summer manduca feeds on "bat-adapted" agave spp. (agaveacea) flowers, and only use datura when it is at peak bloom. manduca's nectar-ho ... | 2008 | 19704447 |
| insect eggs protected from high temperatures by limited homeothermy of plant leaves. | virtually all aspects of insect biology are affected by body temperature, and many taxa have evolved sophisticated temperature-control mechanisms. all insects, however, begin life as eggs and lack the ability to thermoregulate. eggs laid on leaves experience a thermal environment, and thus a body temperature, that is strongly influenced by the leaves themselves. because plants can maintain leaf temperatures that differ from ambient, e.g. by evapotranspiration, plant hosts may protect eggs from e ... | 2009 | 19837886 |
| neural correlates of behavior in the moth manduca sexta in response to complex odors. | with manduca sexta as a model system, we analyzed how natural odor mixtures that are most effective in eliciting flight and foraging behaviors are encoded in the primary olfactory center in the brain, the antennal lobe. we used gas chromatography coupled with multiunit neural-ensemble recording to identify key odorants from flowers of two important nectar resources, the desert plants datura wrightii and agave palmeri, that elicited responses from individual antennal-lobe neurons. neural-ensemble ... | 2009 | 19907000 |
| antagonistic effects of floral scent in an insect-plant interaction. | in southwestern usa, the jimsonweed datura wrightii and the nocturnal moth manduca sexta form a pollinator-plant and herbivore-plant association. because the floral scent is probably important in mediating this interaction, we investigated the floral volatiles that might attract m. sexta for feeding and oviposition. we found that flower volatiles increase oviposition and include small amounts of both enantiomers of linalool, a common component of the scent of hawkmoth-pollinated flowers. because ... | 2010 | 20335210 |
| production of induced volatiles by datura wrightii in response to damage by insects: effect of herbivore species and time. | natural enemies of herbivorous insects utilize numerous chemical cues to locate and identify their prey. among these, volatile plant compounds produced after attack by herbivores may play a significant role (hereafter herbivore-induced plant volatiles or hipvs). one unresolved question is whether the composition of the volatile cue blends induced by different herbivore species differ consistently enough to indicate not only that the plants are damaged by herbivores but also the identity of the h ... | 2011 | 21691808 |
| species-specific effects of herbivory on the oviposition behavior of the moth manduca sexta. | in southwestern usa, the jimsonweed datura wrightii and the nocturnal sphinx moth manduca sexta form a pollinator-plant and herbivore-plant association. while certain plant volatile organic compounds (vocs) attract moths for oviposition, it is likely that other host-derived olfactory cues, such as herbivore-induced vocs, repel moths for oviposition. here, we studied the oviposition preference of female m. sexta towards intact and damaged host plants of three species: d. wrightii, d. discolor (a ... | 2012 | 23274850 |
| intraspecific combinations of flower and leaf volatiles act together in attracting hawkmoth pollinators. | insects pinpoint mates, food and oviposition sites by olfactory cues. recognizing and localizing a suitable target by olfaction is demanding. odor sources emit characteristic blends of compounds that have to be identified against an environmentally derived olfactory background. this background, however, does not necessarily disturb the localization of a source. rather, the contrary. sex pheromones become more attractive to male moths when being presented against a relevant plant background. here ... | 2013 | 24069159 |
| growth and the uptake of sucrose and mineral ions by transformed root cultures of datura stramonium, datura candida x aurea, datura wrightii, hyoscyamus muticus and atropa belladonna. | growth and the uptake of sucrose, anions (cl(-), no3(-), po4(3-), and so4(2-)), and cations (k(+), na(+), mg(2+), ca(2+), and nh4(+)) by transformed roots of datura stramonium, datura wrightii. datura candida x datura aurea hybrid, hyoscyamus muticus, and atropa belladonna were examined during batch culture over 28 days in modified 14 litre stirred tank reactors containing gamborg's b5 salts medium. all cultures completely removed nh4(+) and po4(3-) from the medium, and mg(2+) was totally remove ... | 1995 | 17238087 |
| chromosomal characteristics and occurrence of main alkaloids in datura stramonium and datura wrightii. | the population of datura stramonium l. var. tatula torr and datura wrightii regel was heterogenous in the numerical and structural composition of karyotypes. datura wrightii regel contained, as well as aneuploid sets, a 35% karyotype with a diploid set of chromosomes (2n = 24); there were no chromosomes with satellites and there were 1-2 microchromosomes in 29.6% of the metaphases. datura stramonium l. var. tatula torr included biotypes with a chromosome number of 21-25; in 88.5% of the metaphas ... | 1981 | 17401857 |
| innate and learned olfactory responses in a wild population of the egg parasitoid trichogramma (hymenoptera: trichogrammatidae). | parasitoid insects face the fundamental problem of finding a suitable host in environments filled with competing stimuli. many are deft sensors of olfactory cues emitted by other insects and the plants they live on, and use these cues to find hosts. using olfactory cues from host-plants is effective because plants release volatile organic compounds (vocs), in response to herbivory or oviposition, that contain information about the presence of hosts. however, plant-produced cues can also be misle ... | 2016 | 27965403 |
| trichobaris weevils distinguish amongst toxic host plants by sensing volatiles that do not affect larval performance. | herbivorous insects use plant metabolites to inform their host plant selection for oviposition. these host-selection behaviours are often consistent with the preference-performance hypothesis; females oviposit on hosts that maximize the performance of their offspring. however, the metabolites used for these oviposition choices and those responsible for differences in offspring performance remain unknown for ecologically relevant interactions. here, we examined the host-selection behaviours of tw ... | 2016 | 27146082 |
| protection via parasitism: datura odors attract parasitoid flies, which inhibit manduca larvae from feeding and growing but may not help plants. | insect carnivores frequently use olfactory cues from plants to find prey or hosts. for plants, the benefits of attracting parasitoids have been controversial, partly because parasitoids often do not kill their host insect immediately. furthermore, most research has focused on the effects of solitary parasitoids on growth and feeding of hosts, even though many parasitoids are gregarious (multiple siblings inhabit the same host). here, we examine how a gregarious parasitoid, the tachinid fly drino ... | 2015 | 26298191 |
| sensory biology. flower discrimination by pollinators in a dynamic chemical environment. | pollinators use their sense of smell to locate flowers from long distances, but little is known about how they are able to discriminate their target odor from a mélange of other natural and anthropogenic odors. here, we measured the plume from datura wrightii flowers, a nectar resource for manduca sexta moths, and show that the scent was dynamic and rapidly embedded among background odors. the moth's ability to track the odor was dependent on the background and odor frequency. by influencing the ... | 2014 | 24970087 |
| antiproliferative withanolides from several solanaceous species. | to date, our work on solanaceous species (datura wrightii, jaborosa caulescens, physalis hispida, physalis longifolia, vassobia breviflora and withania somnifera) has resulted in the isolation of 65 withanolides, 31 of which were new, as well as the semi-synthesis of a further 30 withanolides. structure identification and mts assay-based antiproliferative evaluation of these 95 compounds revealed that a δ(2)-1-oxo functionality in ring a, in conjunction with either a 5β,6β-epoxy or 5α-chloro-6β- ... | 2014 | 24871278 |
| host plant odors represent immiscible information entities - blend composition and concentration matter in hawkmoths. | host plant choice is of vital importance for egg laying herbivorous insects that do not exhibit brood care. several aspects, including palatability, nutritional quality and predation risk, have been found to modulate host preference. olfactory cues are thought to enable host location. however, experimental data on odor features that allow choosing among alternative hosts while still in flight are not available. it has previously been shown that m. sexta females prefer datura wrightii compared to ... | 2013 | 24116211 |
| multimodal floral signals and moth foraging decisions. | combinations of floral traits - which operate as attractive signals to pollinators - act on multiple sensory modalities. for manduca sexta hawkmoths, how learning modifies foraging decisions in response to those traits remains untested, and the contribution of visual and olfactory floral displays on behavior remains unclear. | 2013 | 23991154 |
| feeding-induced rearrangement of green leaf volatiles reduces moth oviposition. | the ability to decrypt volatile plant signals is essential if herbivorous insects are to optimize their choice of host plants for their offspring. green leaf volatiles (glvs) constitute a widespread group of defensive plant volatiles that convey a herbivory-specific message via their isomeric composition: feeding of the tobacco hornworm manduca sexta converts (z)-3- to (e)-2-glvs thereby attracting predatory insects. here we show that this isomer-coded message is monitored by ovipositing m. sext ... | 2013 | 23682312 |
| antiproliferative withanolides from datura wrightii. | a new withanolide, named withawrightolide (1), and four known withanolides (2-5) were isolated from the aerial parts of datura wrightii. the structure of compound 1 was elucidated through 2d nmr and other spectroscopic techniques. in addition, the structure of withametelin l (2) was confirmed by x-ray crystallographic analysis. using mts viability assays, withanolides 1-5 showed antiproliferative activities against human glioblastoma (u251 and u87), head and neck squamous cell carcinoma (mda-198 ... | 2013 | 23252848 |
| abiotic induction affects the costs and benefits of inducible herbivore defenses in datura wrightii. | we evaluated the costs and benefits of continuous high-level expression of defenses relative to naturally-induced defenses in field-grown datura wrightii in the presence and absence of herbivores. we induced d. wrightii plants with monthly applications of the plant hormone methyl jasmonate (meja) and assessed levels of inducible proteinase inhibitors (pins). meja application increased pin production by 124 %, whereas the increase in pins due to herbivory was more modest (36 %). pin induction was ... | 2012 | 22932865 |
| herbivory of wild manduca sexta causes fast down-regulation of photosynthetic efficiency in datura wrightii: an early signaling cascade visualized by chlorophyll fluorescence. | plants experiencing herbivory suffer indirect costs beyond direct loss of leaf area, but differentially so based on the herbivore involved. we used a combination of chlorophyll fluorescence imaging and gas exchange techniques to quantify photosynthetic performance, the efficiency of photochemistry, and heat dissipation to examine immediate and longer-term physiological responses in the desert perennial datura wrightii to herbivory by tobacco hornworm, manduca sexta. herbivory by colony-reared la ... | 2012 | 22576017 |
| production of herbivore-induced plant volatiles is constrained seasonally in the field but predation on herbivores is not. | natural enemies of herbivorous insects utilize numerous cues to locate and identify their prey. one class of such cues is volatile organic compounds (vocs) often produced by plants after attack by herbivores (hereafter herbivore-induced plant volatiles or hipvs). under simplified laboratory conditions, natural enemies often make clear choices between different hipv blends, but such clear choices may be more difficult in more complex field environments. we studied the impact of voc production by ... | 2011 | 21484445 |
| ontogeny and season constrain the production of herbivore-inducible plant volatiles in the field. | herbivores may induce plants to produce an array of volatile organic compounds (herbivore-induced plant volatiles, or hipvs) after damage, and some natural enemies of herbivores are attracted by those hipvs. the production of hipvs by the undomesticated species datura wrightii was quantified in response to damage by its natural community of herbivores or the plant hormone methyl jasmonate (meja) over plant's 6-month growing season. patterns of hipv production were compared to the seasonal abunda ... | 2010 | 21058044 |
| variation in herbivore and methyl jasmonate-induced volatiles among genetic lines of datura wrightii. | many plant species produce volatile organic compounds after being damaged by herbivores. the production of volatiles also may be induced by exposing plants to the plant hormone, jasmonic acid, or its volatile ester, methyl jasmonate. this study addresses the induction of the production volatile organic compounds among genetic lines of datura wrightii. within populations, some plants produce glandular trichomes, whereas others produce nonglandular trichomes, and trichome phenotype is controlled b ... | 2007 | 17960462 |
| constitutive and jasmonate-inducible traits of datura wrightii. | plants in the family solanaceae possess numerous traits that are induced from damage from herbivores. many of these also can be induced by exposing plants to the plant hormone jasmonic acid or its volatile ester methyl jasmonate. datura wrightii (solanaceae) is dimorphic for leaf trichome morphology in most southern california populations. trichome phenotype is governed by a single gene, and the glandular trichome condition is dominant and under developmental control. this study addressed two ma ... | 2006 | 16525868 |
| indirect cost of a defensive trait: variation in trichome type affects the natural enemies of herbivorous insects on datura wrightii. | the costs and benefits of defensive traits in plants can have an ecological component that arises from the effect of defenses on the natural enemies of herbivores. we tested if glandular trichomes in datura wrightii, a trait that confers resistance to several species of herbivorous insects, impose an ecological cost by decreasing rates of predation by the natural enemies of herbivores. for two common herbivores of d. wrightii, lema daturaphila and tupiocoris notatus, several generalized species ... | 2005 | 15800744 |
| no benefit of glandular trichome production in natural populations of datura wrightii? | populations of datura wrightii vary in the frequency of plants that produce glandular trichomes, a resistance trait under the control of a single gene. such variation may be maintained if the production of glandular trichomes is costly in the absence of herbivory, and if selection imposed by herbivore communities varies spatially or temporally. here, we document costs in the presence of herbivory for established glandular plants relative to established non-glandular plants growing in natural pop ... | 2000 | 28308744 |
| mydriasis from datura wrightii. | a 4-year-old girl had painless, uniocular mydriasis after picking flowers. pharmacologic testing with 1% pilocarpine confirmed the probability that an atropine-like agent had been instilled in the affected eye. the flowers were identified as datura wrightii and contained scopolamine, hyoscyamine, and atropine on thin-layer chromatography. | 1977 | 888896 |