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Host Plant Species (host + plant_species)
Kinds of Host Plant Species Selected AbstractsPatterns of interspecific associations of stem gallers on willowsDIVERSITY AND DISTRIBUTIONS, Issue 6 2003Jens-Peter Kopelke Abstract., The pattern of interspecific associations of three stem-galling sawfly species (Euura atra, E. elaeagnos, E. purpureae) and three stem-galling gallmidge species (Rabdophaga sp. 3,5) was investigated on five willow taxa (Salix alba, S. fragilis, S. × rubens, S. elaeagnos, S. purpurea) at five natural sites in Central Europe. The willow species harboured specific species associations of two stem gallers, each pair consisting of one Euura and one Rabdophaga species. The stem gallers were patchily distributed and their densities varied significantly among willow host plant species, host plant individuals, and host plant sexes. Four of the six species showed a significant increase in galling rate with shoot length. The other two species were the sawfly and cecidomyiid pair that induce galls on S. purpurea. The preference of stem gallers to longer shoots was generally not related to higher larval performance in terms of survival. Only one species, Rabdophaga sp. 5, was found to be more abundant on male plants. The correlation of densities of the species pairs of stem gallers was independent of willow sexes. Species pairs of stem gallers co-occurring on the same willow species tended to attack different shoots within the same host plant individual. When species pairs co-occurred on shoots they were usually found in similar densities as when occurring alone on shoots. The stem-galling sawflies usually formed galls at the basal part of a shoot, whereas the gallmidge R. sp. 5 (R. sp. 3 and R. sp. 4 showed no clear tendency) preferred the middle or distal part of a shoot. This is interpreted with differences of their phenology and oviposition period. [source] Feeding and breeding across host plants within a locality by the widespread thrips Frankliniella schultzei, and the invasive potential of polyphagous herbivoresDIVERSITY AND DISTRIBUTIONS, Issue 5 2000M. Milne Abstract. Polyphagous insect herbivores could be expected to perform relatively well in new areas because of their ability to exploit alternative resources. We investigated relative abundance patterns of the polyphagous thrips species Frankliniella schultzei, which is characteristically found on plants from many different families, to establish the role of different host plant species in a single locality where the species is not indigenous (Brisbane, south-eastern Queensland, Australia). F. schultzei females and larvae were always present in flowers (where oviposition takes place) and never on leaves of the eight plant species that we surveyed regularly over one year. They were present in flowers of Malvaviscus arboreus in much higher densities than for any other host. F. schultzei females were more fecund and larvae developed faster on floral tissue diets of M. arboreus than on those of other hosts. M. arboreus is therefore regarded as the ,primary' host plant of F. schultzei in the locality that we investigated. The other species are regarded as ,minor' hosts. Available evidence indicates a common geographical origin of F. schultzei and M. arboreus. F. schultzei may therefore be primarily adapted to M. arboreus. The flowers of the minor species on which F. schultzei is also found may coincidentally share some features of the primary host. Adult thrips may therefore accumulate on minor hosts and breed there, but to a lesser extent than on the primary host. The general implications for investigating polyphagous host relationships and interpreting the ecology of these species as generalist invaders are spelt out. [source] Thrips see red , flower colour and the host relationships of a polyphagous anthophilic thripsECOLOGICAL ENTOMOLOGY, Issue 5 2007A. YAKU Abstract 1.,The common blossom thrips, Frankliniella schultzei, is a polyphagous anthophilic species that colonises a wide range of host-plant species across different plant taxa. The environmental cues used by these polyphagous insects to recognise and locate host plants are not known. We therefore determined if colour is an important environmental signal used by F. schultzei to recognise flowers of eight of its more significant host-plant species. 2.,The effect of flower colour on the colonisation of different host plant species by F. schultzei was investigated by collecting and analysing the following: (a) numbers of thrips from different heights and aspects of the primary host plant Malvaviscus arboreus, (b) thrips distribution within flowers of Hibiscus rosasinensis, (c) colour reflectance from flowers of eight different host-plant species, and (d) reflectance from different coloured sticky traps and the number of thrips trapped on them at different times of the day and on different dates. 3.,The results indicate that: (a) the thrips (both sexes) concentrate towards the top of the primary host plant M. arboreus and are not distributed differentially according to sunny or shady aspect of the plant, (b) the number of female thrips on H. rosasinensis was higher in anthers compared to petals (corolla) and the basal parts of the flower, and males were as numerous on the petals as were females, and (c) there is a common floral reflectance pattern (but with different intensities) across the eight host plant species, mainly in the red part of the spectrum (600,700 nm). 4.,Results of colour sticky trapping show that red attracts more female thrips compared to any other colour and that most were caught between 09.00 and 11.00 hours. By contrast, more male thrips were trapped between 07.00 and 09.00 hours. Males were more evenly distributed across the different colours but the highest numbers were associated with the yellow traps. 5.,The higher densities of thrips at the top of their host plant may be related to the early morning (07.00,11.00 hours) activity of the thrips, when the top portions of the plant are more exposed to sunlight. The sex-related distributions of F. schultzei thrips across time, coloured sticky traps, and various parts of the flowers seem to be related to mating swarm formation by the males, on the one hand, and the relative frequency and intensity of the use of M. arboreus by the females, on the other, as a feeding and oviposition site. Frankliniella schultzei females respond more strongly to red than to any other colours, so it is predicted that the spectral properties of colour recognition by this species will correlate with the predominant red reflectance of its primary host, M. arboreus, and that there may well be a sex-related difference in colour recognition within this species. [source] Foraging in nature: foraging efficiency and attentiveness in caterpillars with different diet breadthsECOLOGICAL ENTOMOLOGY, Issue 4 2004E. A. Bernays Abstract., 1. Seventy-seven individual last-instar caterpillars foraging in the field were examined for 6 h each. They represented four species of Arctiidae of similar size and habitat use. Two, Hypocrisias minima and Pygarctia roseicapitis, are specialists restricted to particular plant genera. The other two, Grammia geneura and Estigmene acrea, are extreme generalists that use many host plant species from multiple plant families. 2. Parameters of behavioural efficiency were monitored. Generalists spent more time walking, rejected more potential host plants, took longer to decide to feed after inspecting a plant, and took relatively more small feeding bouts compared with specialists. 3. This is the first test of differential foraging efficiency in the field in relation to diet breadth of insects and the data indicate that generalists are less efficient in their foraging activities and may suffer from divided attention. The need for attentiveness to enhance efficiency and thereby reduce ecological risk is discussed. [source] Host shifting by Operophtera brumata into novel environments leads to population differentiation in life-history traitsECOLOGICAL ENTOMOLOGY, Issue 5 2003Adam J. Vanbergen Abstract., 1. Operophtera brumata L. (Lepidoptera: Geometridae), a polyphagous herbivore usually associated with deciduous trees such as oak Quercus robur L., has expanded its host range to include the evergreen species heather Calluna vulgaris (L.) Hull and, most recently, Sitka spruce Picea sitchensis (Bong.) Carrière. 2. Phenology, morphology, and survival of O. brumata were measured at several life-history stages in populations from the three different host plant communities sampled from a range of geographical locations. The data were used to test for population differences, reflecting the marked differences in host-plant secondary chemistry, growth form, and site factors such as climate. The hypothesis that spruce-feeding populations originated from populations feeding on moorland, commonly sites of coniferous afforestation, was also tested. 3. Altitude, not host plant species, was the major influence on the timing of adult emergence. An effect of insect population independent of altitude was found, implying that additional unidentified factors contribute to this phenological variation. Larval survival and adult size varied between populations reared on different host plant species. Survival of larvae was affected negatively when reared on the novel host plant, Sitka spruce, versus the natal plant (oak or heather) but oak and heather-sourced insects did not differ in survivorship on Sitka spruce. 4. Host range extension into novel environments has resulted in population differentiation to the local climate, demonstrating that host shifts pose challenges to the herbivore population greater than those offered by the host plant alone. The hypothesis that Sitka spruce feeding populations have arisen predominantly from moorland feeding populations was not supported. [source] Four ways towards tropical herbivore megadiversityECOLOGY LETTERS, Issue 4 2008Thomas M. Lewinsohn Abstract Most multicellular species alive are tropical arthropods associated with plants. Hence, the host-specificity of these species, and their diversity at different scales, are keys to understanding the assembly structure of global biodiversity. We present a comprehensive scheme in which tropical herbivore megadiversity can be partitioned into the following components: (A) more host plant species per se, (B) more arthropod species per plant species, (C) higher host specificity of herbivores, or (D) higher species turnover (beta diversity) in the tropics than in the temperate zone. We scrutinize recent studies addressing each component and identify methodological differences among them. We find substantial support for the importance of component A, more tropical host species. A meta-analysis of published results reveals intermediate to high correlations between plant and herbivore diversity, accounting for up to 60% of the variation in insect species richness. Support for other factors is mixed, with studies too scarce and approaches too uneven to allow for quantitative summaries. More research on individual components is unlikely to resolve their relative contribution to overall herbivore diversity. Instead, we call for the adoption of more coherent methods that avoid pitfalls for larger-scale comparisons, for studies assessing different components together rather than singly, and for studies that investigate herbivore beta-diversity (component D) in a more comprehensive perspective. [source] Searching and oviposition behavior of a mymarid egg parasitoid, Anagrus nigriventris, on five host plant species of its leafhopper host, Circulifer tenellusENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 1 2000A.K. Al-Wahaibi Abstract Searching and oviposition behavior and parasitization ability of Anagrus nigriventris Girault (Hymenoptera: Mymaridae), an egg parasitoid of beet leafhopper, Circulifer tenellus (Baker) (Homoptera: Cicadellidae), were examined on five host plant species of beet leafhopper: sugar beet (Beta vulgaris L.), red stem filaree (Erodium cicutarium[L.]), peppergrass (Lepidium nitidum Nuttall), desert plantain (Plantago ovata Forsskal), and London rocket (Sisymbrium irio L.). Beet leafhopper embeds its eggs in the tissues of these plant species. For each plant species, A. nigriventris behavior was examined on plants with and without beet leafhopper eggs. Experimental design was a 5 (plant species) by 2 (host eggs present/absent) factorial. Additionally within each treatment, parasitoid behavior was observed over a 22-h period at five different observation periods: t=0, 3, 6, 9, and 22 h where t=0 h represents initial exposure of the insect with the plant. The behavioral events observed were: ,fast walking' (general searching), ,slow walking' (intensive searching), ovipositor probing, grooming, feeding, and resting. Significant differences (,=0.05) among plant species in time spent on the plant, percentage of host eggs parasitized, and behavioral variables associated with intensive searching and oviposition all indicated that the plant species fell into two groups: ,preferred' plants (sugar beet, London rocket, and peppergrass), and ,unpreferred' plants (filaree and plantago). These variables also indicated that the parasitoids spent more time on, searched more, probed more, and oviposited more in plants with host eggs than plants without host eggs. Consistent effects of time (over the observation periods from t=0 to t=22 h) generally were detected only in the preferred plant species that had host eggs present. In these cases, intensive searching and probing decreased as time advanced, while variables related to general searching (,fast walking') and abandoning host egg patches (leaving the plant) tended to increase over time. [source] Forty-nine new host plant species for Bemisia tabaci (Hemiptera: Aleyrodidae)ENTOMOLOGICAL SCIENCE, Issue 4 2008Alvin M. SIMMONS Abstract The sweetpotato whitefly, Bemisia tabaci (Gennadius), is a worldwide pest of numerous agricultural and ornamental crops. In addition to directly feeding on plants, it also acts as a vector of plant viruses of cultivated and uncultivated host plant species. Moreover, host plants can affect the population dynamics of whiteflies. An open-choice screening experiment was conducted with B-biotype B. tabaci on a diverse collection of crops, weeds, and other indigenous plant species. Five of the plant species were further evaluated in choice or no-choice tests in the laboratory. The results reveal 49 new reproductive host plant species for B. tabaci. This includes 11 new genera of host plants (Arenaria, Avena, Carduus, Dichondra, Glechoma, Gnaphalium, Molugo, Panicum, Parthenocissus, Trianthema, and Triticum) for this whitefly. All species that served as hosts were acceptable for feeding, oviposition, and development to the adult stage by B. tabaci. The new hosts include three cultivated crops [oats (Avena sativa L.), proso millet (Panicum miliaceum L.), and winter wheat (Triticum aestivum L.)], weeds and other wild species, including 32 Ipomoea species, which are relatives of sweetpotato [I. batatas (L.) Lam.)]. Yellow nutsedge, Cyperus esculentus L., did not serve as a host for B. tabaci in either open-choice or no-choice tests. The results presented herein have implications for whitefly ecology and the numerous viruses that B. tabaci spreads to and among cultivated plants. [source] Faunal make-up, host range and infestation rate of weevils and tephritid flies associated with flower heads of the thistle Cirsium (Cardueae: Astaraceae) in JapanENTOMOLOGICAL SCIENCE, Issue 4 2004Akinori NAKAMURA Abstract From 1988 to 1998, we collected flower heads of 39 thistle taxa (35 taxa of Cirsium, one species each of Breea, Synurus, Saussurea and Arctium; Cardueae; Astaraceae) in Japan, mainly from Hokuriku and other parts of central Honshu, and kept them in the laboratory to breed weevils and tephritid flies, the core fauna. We report the faunal make-up, host plants, geographic distribution and the attack levels of the insects. Results indicated that (i) three Larinus species (Curculionidae) and three species of tephritid flies (Tephritis, Urophora and Xyphosia) comprised the core fauna; (ii) two insect species belonging to the same taxonomic group (either Curculionidae (Larinus) or Tephritidae) tended to use different host plant species; (iii) two sympatric Larinus species (L. latissimus and L. meleagris) segregated the host plants seasonally in central Honshu (Cirsium blooming in spring and autumn, respectively); and (iv) two tephritid fly species, Xyphosia punctigera and Urophora sachalinensis, segregated geographically (the former on the Japan Sea side and the latter on the Pacific Ocean side). In comparison with their European counterparts, the weevils and tephritids of the Japanese Cirsium are characterized by a lower species richness and a lower degree of specialization in usage of the thistle flower heads, with gall-formers being distinctly under-represented, and callus tissue-feeders being absent. This reflects the fact that Japanese thistles are so closely related that hybridization frequently occurs, and also that the thistles have had a short history of interaction with the insects since the thistles' arrival in Japan. [source] Plant nitrogen acquisition and interactions under elevated carbon dioxide: impact of endophytes and mycorrhizaeGLOBAL CHANGE BIOLOGY, Issue 6 2007XIN CHEN Abstract Both endophytic and mycorrhizal fungi interact with plants to form symbiosis in which the fungal partners rely on, and sometimes compete for, carbon (C) sources from their hosts. Changes in photosynthesis in host plants caused by atmospheric carbon dioxide (CO2) enrichment may, therefore, influence those mutualistic interactions, potentially modifying plant nutrient acquisition and interactions with other coexisting plant species. However, few studies have so far examined the interactive controls of endophytes and mycorrhizae over plant responses to atmospheric CO2 enrichment. Using Festuca arundinacea Schreb and Plantago lanceolata L. as model plants, we examined the effects of elevated CO2 on mycorrhizae and endophyte (Neotyphodium coenophialum) and plant nitrogen (N) acquisition in two microcosm experiments, and determined whether and how mycorrhizae and endophytes mediate interactions between their host plant species. Endophyte-free and endophyte-infected F. arundinacea varieties, P. lanceolata L., and their combination with or without mycorrhizal inocula were grown under ambient (400 ,mol mol,1) and elevated CO2 (ambient + 330 ,mol mol,1). A 15N isotope tracer was used to quantify the mycorrhiza-mediated plant acquisition of N from soil. Elevated CO2 stimulated the growth of P. lanceolata greater than F. arundinacea, increasing the shoot biomass ratio of P. lanceolata to F. arundinacea in all the mixtures. Elevated CO2 also increased mycorrhizal root colonization of P. lanceolata, but had no impact on that of F. arundinacea. Mycorrhizae increased the shoot biomass ratio of P. lanceolata to F. arundinacea under elevated CO2. In the absence of endophytes, both elevated CO2 and mycorrhizae enhanced 15N and total N uptake of P. lanceolata but had either no or even negative effects on N acquisition of F. arundinacea, altering N distribution between these two species in the mixture. The presence of endophytes in F. arundinacea, however, reduced the CO2 effect on N acquisition in P. lanceolata, although it did not affect growth responses of their host plants to elevated CO2. These results suggest that mycorrhizal fungi and endophytes might interactively affect the responses of their host plants and their coexisting species to elevated CO2. [source] Species diversity of lepidopteran stem borer parasitoids in cultivated and natural habitats in KenyaJOURNAL OF APPLIED ENTOMOLOGY, Issue 6 2009D. M. Mailafiya Abstract Field surveys were conducted during 2005 to 2007 to assess the species diversity of stem borer parasitoids in cultivated and natural habitats in four agroecological zones in Kenya. In total, 33 parasitoid species were recovered, of which 18 parasitized six stem borer species feeding on cereal crops, while 27 parasitized 21 stem borer species feeding on 19 wild host plant species. The most common parasitoids in cultivated habitats were Cotesia flavipes Cameron, Cotesia sesamiae (Cameron), Pediobius furvus Gahan and the tachinid Siphona sp., whereas in natural habitats, Siphona sp. was the most common. The majority of parasitoids were stenophagous species; only five species ,Cotesia sp., Enicospilus ruscus Gauld and Mitchell, Pristomerus nr. bullis, Sturmiopsis parasitica (Curran) and Syzeuctus ruberrimus Benoit , were monophagous. In both cultivated and natural habitats, parasitoid species diversity was highest on the most dominant stem borers Busseola spp. and Chilo spp. On cereal crops, parasitoid diversity was highest on maize and among wild host plants, it was highest on Setaria spp. The ingress-and-sting attack method was the most common strategy used by parasitoids in both habitats. In all agroecological zones, parasitoid species diversity was significantly higher in natural than in cultivated habitats. Furthermore, the majority of parasitoid species were common to both cultivated and natural habitats. It was concluded that natural habitats surrounding cereal crops serve as refugia for sustaining the diversity of stem borer parasitoids from adjacent cereal fields. [source] Resource specialization in a phytophagous insect: no evidence for genetically based performance trade-offs across hosts in the field or laboratoryJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 4 2009S. J. AGOSTA Abstract We present a field test of the genetically based performance trade-off hypothesis for resource specialization in a population of the moth Rothschildia lebeau whose larvae primarily feed on three host plant species. Pairwise correlations between growth vs. growth, survival vs. survival and growth vs. survival across the different hosts were calculated, using families (sibships) as the units of analysis. Of 15 pairwise correlations, 14 were positive, 5 significantly so and none were negative. The same pattern was found using complementary growth and survival data from the laboratory. Overall, we found no evidence of negative genetic correlations in cross-host performance that would be indicative of performance trade-offs in this population. Rather, variation among families in performance appears to reflect ,general vigour' whereby families that perform well on one host perform well across multiple hosts. We discuss the implications of positive genetic correlations in cross-host performance in terms of the ecology and evolution of host range. We argue that this genetic architecture facilitates colonization of novel hosts and recolonization of historical hosts, therefore contributing to host shifts, host range expansions, biological invasions and introductions, and host ranges that are regionally broad but locally narrow. [source] Non-target habitat exploitation by Trichogramma brassicae (Hym. Trichogrammatidae): what are the risks for endemic butterflies?AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2003D. Babendreier Abstract 1,Trichogramma brassicae Bezdenko is inundatively released against the European corn borer in Switzerland. Because parasitoids dispersing from the release fields might pose a threat to native butterflies, the searching efficiency of T. brassicae was investigated in nontarget habitats. 2,In field studies, T. brassicae was released at rates of 120 000 females/ha. Parasitism of sentinel Ephestia kuehniella egg clusters was 1.6,3.6% in meadows and 2.0,4.0% in flower strips. The respective figures were 57.6,66.7% and 19.2,46.9% in maize, significantly higher than the parasitism rates in the nontarget habitats. Experiments carried out in small field cages confirmed these results: Again, significantly higher parasitism rates were found in maize compared to meadows and flower strips, and also compared to hedgerows (in sleeve cages). 3,To elucidate potential factors underlying the low searching efficiency in nontarget habitats, the behaviour of individual T. brassicae females was investigated on four meadow plants comparatively to maize and a filter paper control. Mean (±SE) walking speed on maize was 2.2 ± 0.2 mm/s, similar to three of the plants tested and filter paper but significantly higher than on Trifolium pratense (0.85 mm/s). A higher turning rate was found on T. pratense, Viola wittrockiana and Plantago lanceolata, in contrast to the longer leaved maize and Alopecurus pratensis. The number of wasps leaving the plant within the observation period differed significantly between plant species, and was twice as high for T. pratense (and the filter paper control) compared to the other plant species. 4,In a choice experiment carried out in a climate cabinet with all five host plant species in cages, we obtained the highest parasitism rates on maize and the lowest parasitism on T. pratense, thus confirming the behavioural observations. 5,In conclusion, there is evidence for a decreased searching efficiency on plants in nontarget habitats compared to maize. However, the data explain only part of the differences found between parasitism in maize compared to nontarget habitats. Other factors, such as the structural complexity of a habitat, may also play a role. We conclude that the risk for butterfly populations in the tested nontarget habitat due to mass released T. brassicae is low. [source] Differential Growth Inhibition of Diaporthe and Phomopsis Isolates by the Metabolic Activity of Five ActinomycetesJOURNAL OF PHYTOPATHOLOGY, Issue 5 2000M. Munta ñola-Cvetkovic Fifty-five cultures derived from Diaporthe perithecia and Phomopsis pycnidia found on diverse host plant species collected at different times and sites in Vojvodina, Yugoslavia, showed distinguishing quantitative reactions to the fungistatic activity of five actinomycetes obtained as fortuitous laboratory contaminants coming from field material. Streptomyces albidoflavus, S. albus, S. diastaticus, Streptomyces sp., and Streptoverticillium sp. could be ranked by their growth-inhibitory potential, with S. albus showing the strongest, and Streptomyces sp. the lowest. The responses of the fungi varied depending on the tested actinomycetes, but two major groups could be distinguished: A, which encompased the isolates that were less affected by the proximity of the actinomycetes; and B, with those which exhibited high sensitivity in all the experiments. Group A was typically represented by Diaporthe arctii, Phomopsis longicolla, and the Phomopsis type-1 cultures from Xanthiumitalicum; group B was typically represented by Diaporthe/Phomopsis helianthi,Phomopsis type-2 cultures from X. italicum, and isolates from Lactuca serriola. The results obtained underscore the dissimilarities between D. arctii and D. helianthi, and corroborate the value of the physiological aspects of congeneric isolates in considering taxonomic problems in the coelomicete genus Phomopsis. Zusammenfassung Aus Diaporthe -Perithecien und Phomopsis -Pyknidien von verschiedenen Wirtspflanzenarten, die zu unterschiedlichen Zeitpunkten und an verschiedenen Orten in der jugoslawischen Vojvodina gesammelt worden waren, wurden 55 Kulturen gewonnen. Die Isolate zeigten charakteristische quantitative Reaktionen auf die fungistatische Aktivität von fünf Actinomyceten, die im Labor als Zufallskontaminanten auftraten und von Feldmaterial stammten. Streptomyces albidoflavus, S. albus, S. diastaticus, Streptomyces sp. und Streptoverticillium sp. konntenihrem wachstumshemmenden Potential entsprechend geordnet werden, wobei S. albus die stärkste und Streptomyces sp. die niedrigste Hemmung zeigte. Die Reaktionen der Pilze variierten in Abhängigkeit von den getesteten Actinomyceten, doch zwei Hauptgruppen lie,en sich unterscheiden: Gruppe A umf,te die Isolate, die von der Nähe der Actinomyceten weniger gehemmt wurden, und Gruppe B die Isolate, die bei allen Versuchen eine hohe Sensitivität zeigten. Typische Vertreter der Gruppe A waren Diaporthe arctii, Phomopsis longicolla sowie die von Xanthium italicum stammenden Phomopsis -Kulturen vom Typ 1. Typische Repräsentanten der Gruppe B waren Diaporthe/Phomopsis helianthi, die von X. italicum stammenden Phomopsis -Kulturen vom Typ 2 sowie von Lactuca serriola stammende Isolate. Die Ergebnisse verdeutlichen die Unterschiede zwischen D. arctii und D. helianthi und bestätigen die Bedeutung physiologischer Aspekte von Isolaten innerhalb derselben Gattung bei der Betrachtung taxonomischer Probleme in der Coelomyceten-Gattung Phomopsis. [source] Amino acid budgets in three aphid species using the same host plantPHYSIOLOGICAL ENTOMOLOGY, Issue 3 2001J. P. Sandström Abstract. Nutrient provisioning in aphids depends both on the composition of ingested phloem sap and on the biosynthetic capabilities of the aphid and its intracellular symbionts. Amino acid budgets for three aphid species, Rhopalosiphum padi (L.), Schizaphis graminum (Rondani) and Diuraphis noxia (Mordvilko), were compared on a single host plant species, wheat Triticum aestivum L. Ingestion of amino acids from phloem, elimination of amino acids in honeydew, and the content of amino acids in aphids tissue were measured. From these values, ingestion rates were estimated and compared to honeydew and to estimated composition of aphid proteins. Ingestion rate was lowest in D. noxia due to low growth rate and low honeydew production; intermediate in S. graminum due to higher growth rate and intermediate honeydew production; and highest in R. padi, which had the highest rates for both variables. Both D. noxia and S. graminum induced increases in the amino acid content of ingested phloem. These changes in phloem content, combined with differences in ingestion rates, resulted in large differences among aphids in estimated rates of ingestion of individual amino acids. In honeydew, most essential amino acids were found in low amounts compared with the amounts ingested, especially for methionine and lysine. A few amino acids (arginine, cystine, histidine and tryptophan) were more abundant in honeydew of some aphids, suggesting oversupply. Aphid species differed in the composition of free amino acids in tissue but showed very similar composition in protein, implying similar requirements among the aphids. In R. padi and D. noxia, most essential amino acids were ingested in amounts insufficient for growth, implying dependence on symbiont provisioning. In S. graminum, most amino acids were ingested in amounts apparently sufficient for growth. [source] Glutathione S-transferases in the adaptation to plant secondary metabolites in the Myzus persicae aphidARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 3 2005Frédéric Francis Abstract Glutathione S-transferases (GST) in insects play an important role in the detoxification of many substances including allelochemicals from plants. Induction of GST activity in Myzus persicae in response to secondary metabolites from Brassica plants was determined using different host plant species and confirmed using artificial diet with pure allelochemicals added. The 2,4-dinitro-1-iodobenzene (DNIB) was found to be a useful substrate for identifying particular GSTs in insects. GSTs from M. persicae were purified using different affinity chromatography columns and related kinetic parameters were calculated. GST isoenzymes were characterised using electrophoretic methods. Although SDS-PAGE results indicated similarity among the purified enzymes from each affinity column, biochemical studies indicated significant differences in kinetic parameters. Finally, the GST pattern of M. persicae was discussed in terms of insect adaptation to the presence of plant secondary substances such as the glucosinolates and the isothiocyanates, from Brassicaceae host plants. Arch. Insect Biochem. Physiol. 58:166,174, 2005. © 2005 Wiley-Liss, Inc. [source] Significance of a new field oviposition record for Graphium eurypylus (L.) (Lepidoptera: Papilionidae) on Michelia champaca (Magnoliaceae)AUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 1 2008Michelle L Larsen Abstract, Phytochemical similarities among ancient Angiosperms presumably played a role in the ecological and evolutionary diversification of the swallowtail butterflies (Papilionidae). Host family feeding specialisation is typical of most Papilionidae species, but field records of oviposition are rare for most swallowtail butterflies. It is even more uncommon to witness oviposition and larval feeding on new host plant species, especially in plant families not previously reported for the butterfly species. Oviposition by a female on a new host, or even on a toxic plant, may represent ancestral behaviour (with a loss of larval acceptance, detoxification or processing abilities) or novel behaviour (providing genetic variation for a potential expansion of host range, or host shift). We document the oviposition, larval use and pupation of the Annonaceae specialised and geographically widespread Graphium eurypylus on a Magnoliaceae species, all under field conditions in Queensland, Australia. This is the first time such field observations of oviposition and larval feeding on Michelia champaca (Magnoliaceae) have been documented anywhere for this species. [source] | |||||||||||||||||||||||||