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Floral Nectar (floral + nectar)
Selected AbstractsInfluence of different sugars on the longevity of Bathyplectes curculionis (Hym., Ichneumonidae)JOURNAL OF APPLIED ENTOMOLOGY, Issue 4 2004H. Spafford Jacob Abstract:, Floral nectars, homopteran honeydews and honey are known to increase parasitoid longevity. However, these foods are composed of several sugars which may differentially affect longevity. We tested the effects of individual sugars and mixtures on the longevity of Bathyplectes curculionis Thomson (Hym., Ichenumonidae), a natural enemy of the alfalfa weevil. There was a significant difference in the longevity of female wasps on the various diets. Glucose or fructose alone appeared to have the most benefits while trehalose and melezitose were not as useful for increasing wasp longevity. Suitability of these sugars for provisioning food for parasitoids in the field is discussed. [source] Ecology of yeasts in plant,bumblebee mutualism in Central EuropeFEMS MICROBIOLOGY ECOLOGY, Issue 2 2004Michael Brysch-Herzberg Abstract Yeast community involved in plant,bumblebee mutualism was investigated in three successive years. Yeasts were isolated from floral nectar, bumblebee queens after hibernation, bumblebee workers, and the honey provisions in nests. From the distribution of yeast species in the various microhabitats in the course of the year their ecology was assessed. Nectar of numerous plant species belonging to various plant families was analyzed in order to uncover possible impacts on the yeasts present in the nectar. Only ascomycetous yeasts were autochthonous members of the communities in the plant,bumblebee mutualism. Species in the Metschnikowia clade, the Starmarella clade, and the genera Debaryomyces and Zygosaccharomyces were associated with the mutualism. Some species appeared highly specialized, whereas others had a broader distribution. While physical and chemical properties of nectar had only limited influence on the abundance of nectar yeasts, the attractiveness of plants to the flower-visiting insects appears to have had a greater impact on the abundance and frequency of yeasts in the nectar of different plant species. [source] Extrafloral nectar from cotton (Gossypium hirsutum) as a food source for parasitic waspsFUNCTIONAL ECOLOGY, Issue 1 2006U. S. R. RÖSE Summary 1For many adult nectar-feeding parasitoids food and moisture are essential for survival in the field. Early in the season, when floral nectar is not yet available in cotton, extrafloral nectar (EFN) is already present on young cotton plants. 2The parasitoid Microplitis croceipes (Cresson) can use EFN cotton plants as an only food source. The longevity and reproduction of EFN-fed female wasps was comparable to wasps fed with honey and water provided on nectariless (NL) cotton plants, and was significantly higher compared with wasps kept on NL plants with no additional food source. 3Wasps that were given preflight experiences on EFN cotton plants choose EFN cotton over NL cotton plants in two choice experiments in the flight tunnel. The parasitoids are more willing to search on an EFN plant at their second and third encounter with a plant previously visited, compared with an NL cotton plant. 4Wasps can locate EFN from short distances by its odour alone, and find it almost as fast as honey, but much faster than odourless sucrose, which is only found randomly. Experience with EFN increased the retention ability of parasitoids on a flower model. [source] Limited ability of Palestine Sunbirds Nectarinia osea to cope with pyridine alkaloids in nectar of Tree Tobacco Nicotiana glaucaFUNCTIONAL ECOLOGY, Issue 6 2004H. TADMOR-MELAMED Summary 1Secondary compounds are common in floral nectar but their relative effects on nectar consumption and utilization in nectarivorous birds are unclear. 2We studied the effect of two pyridine alkaloids, nicotine and anabasine, present in Tree Tobacco (Nicotiana glauca) nectar, on food consumption, gut transit time and sugar assimilation efficiency of the Palestine Sunbird (Nectarinia osea), a pollinator of N. glauca in east Mediterranean ecosystems. 3Sunbirds demonstrated dose-dependent deterrence; they were not deterred by the lowest natural concentrations of these alkaloids in nectar (0·1 ppm nicotine and 0·6 ppm anabasine) but they were significantly deterred by the average concentrations detected in nectar (0·5 ppm nicotine and 5 ppm anabasine). 4The two pyridine alkaloids reduced gut transit time (by 30,42%) and sugar assimilation efficiency (by 9,17%) compared with the control alkaloid-free diet. 5Sunbirds are able to cope with low, but not average, concentrations of nicotine and anabasine in N. glauca nectar. If sunbirds are efficient pollinators of N. glauca they may induce selection on it to reduce pyridine alkaloid production in the nectar. Alternatively, high concentrations in some N. glauca plants may lead the birds to visit more plants with lower alkaloid concentrations. Hence, they will be more efficient pollinators, especially if other nectar-producing plants are scarce. [source] Development of the herbivore Pieris rapae and its endoparasitoid Cotesia rubecula on crucifers of field edgesJOURNAL OF APPLIED ENTOMOLOGY, Issue 9-10 2006J. A. Harvey Abstract:, Several studies have reported that flowering herbs, which grow naturally or are sown adjacent to agricultural fields, may be an important source of nutrients for natural enemies. Many parasitoids readily feed on plant exudates such as floral nectar, which contain different types of sugars that enable the insects to optimize their longevity, mobility and reproductive success. However, leaf tissues of plants grown in the margins of agricultural fields may also provide food for immature stages of insect herbivores, such as caterpillars, that are in turn attacked by parasitoids. Herbivores and their parasitoids may later disperse into the crop, so the nutritional quality of surrounding plants, as this affects herbivore and parasitoid fitness, may also influence the success of biological control programmes, especially later in the season. Here, we compare the suitability of three species of cruciferous plants (Brassicaceae) on the development of Pieris rapae L. (Lep., Pieridae) and its solitary endoparasitoid, Cotesia rubecula Marshall (Hym., Bracondiae). Insects were reared on a feral population of cabbage, Brassica oleracea, on radish Raphanus sativus, which is widely sown in agricultural margins, and on hedge mustard, Sisymbrium officinale, a wild crucifer which often grows in medium to large stands along road verges and field edges. Development time in both the herbivore and parasitoid were extended on R. sativus, compared with the other two species, whereas C. rubecula completed its development most rapidly on B. oleracea. Moreover, adult butterflies and parasitoids were significantly smaller when reared on R. sativus plants. Our results reveal that differences in the quality of plants growing adjacent to agricultural fields can affect the development of key herbivores and their parasitoids. This should be borne in mind when establishing criteria for the selection of floral biodiversity. [source] Targeted sugar provision promotes parasitism of the cereal leaf beetle Oulema melanopusAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 1 2010Edward W. Evans 1Parasitoids may often lack access to sugar (e.g. floral nectar) in agricultural settings. Strategically timed spraying of host plants with sugar solution may provide one means of enhancing parasitism at the same time as minimizing nontarget effects (e.g. benefiting the pest itself). 2Sucrose was sprayed in wheat fields of northern Utah (U.S.A.) to assess the effects on parasitism of the cereal leaf beetle Oulema melanopus by the larval parasitoid Tetrastichus julis. 3Early-season sugar provisioning, when larvae of the pest were first hatching and parasitoid adults were newly emerged, did not affect the numbers of cereal leaf beetle larvae that matured in treated plots but increased parasitism rates of beetle larvae by four-fold in 2006 and by seven-fold in 2007. 4No net influx of adult parasitoids into plots was detected after the application of sugar. Locally-emerging parasitoids may have spent less time searching for their own food needs versus hosts. A laboratory experiment also confirmed that access to sucrose significantly increased parasitoid longevity. 5The field experimental results obtained demonstrate that applications of sugar, implemented to target a key time of the growing season when benefits are maximized for parasitoids and minimized for their hosts, can strongly promote parasitism of the cereal leaf beetle in wheat fields. [source] Comparing different floral resources on the longevity of a parasitic waspAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 1 2008Livy Williams III Abstract 1,The effects of floral resources of several important non-crop host plants of Lygus lineolaris on the longevity of Anaphes iole, one of its natural enemies, was studied. 2,Median longevity of A. iole wasps provisioned with floral resources (Erigeron annuus, Oenothera speciosa, Lamium amplexicaule, and Capsella bursa-pastoris) was in the range 1.27,3.24 days, and did not differ from wasps in the distilled water only control (1.46,2.81 days), but was less than median longevity of wasps provisioned with distilled water + sucrose (5.30,12.46 days). No difference in longevity was observed between gender, although females usually lived slightly longer than males. 3,High-performance anion-exchange chromatography analyses of O. speciosa floral nectar revealed that the major carbohydrate components were sucrose, glucose, and fructose. 4,The results indicate that the floral resources of some non-crop plants that serve as important reproductive hosts for L. lineolaris offer little or no benefit to A. iole. [source] Pollination in Jacaranda rugosa (Bignoniaceae): euglossine pollinators, nectar robbers and low fruit setPLANT BIOLOGY, Issue 2 2009P. Milet-Pinheiro Abstract Nectar robbers access floral nectar in illegitimate flower visits without, in general, performing a pollination service. Nevertheless, their effect on fruit set can be indirectly positive if the nectar removal causes an incremental increase in the frequency of legitimate flower visits of effective pollinators, especially in obligate outcrossers. We studied pollination and the effect of nectar robbers on the reproductive fitness of Jacaranda rugosa, an endemic shrub of the National Park of Catimbau, in the Caatinga of Pernambuco, Brazil. Xenogamous J. rugosa flowers continuously produced nectar during the day at a rate of 1 ,l·h,1. Female and male Euglossa melanotricha were the main pollinators. Early morning flower visits substantially contributed to fruit set because stigmas with open lobes were almost absent in the afternoon. Ninety-nine per cent of the flowers showed damage caused by nectar robbers. Artificial addition of sugar water prolonged the duration of flower visits of legitimate flower visitors. Removal of nectar, simulating the impact of nectar robbers, resulted in shorter flower visits of euglossine bees. While flower visits of nectar-robbing carpenter bees (Xylocopa frontalis, X. grisescens, X. ordinaria) produced only a longitudinal slit in the corolla tube in the region of the nectar chamber, worker bees of Trigona spinipes damaged the gynoecium in 92% of the flowers. This explains the outstandingly low fruit set (1.5%) of J. rugosa in the National Park of Catimbau. [source] Phylogeny, biogeography, and recurrent evolution of divergent bill types in the nectar-stealing flowerpiercers (Thraupini: Diglossa and Diglossopis)BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2009WILLIAM M. MAUCK III Neotropical tanagers known as flowerpiercers (Diglossa and Diglossopis) have a novel feeding adaptation, comprising a downward curved hook on the maxilla that allows these species to obtain floral nectar without pollination. Using mitochondrial DNA sequences, the phylogenetic relationships of all 18 species of flowerpiercers were studied for the first time. Strong support was found for the monophyly of flowerpiercers and for the monophyly of four superspecies within flowerpiercers. However, previously described species-groups, as well as the genus Diglossopis, are not monophyletic. The biogeographic origin of flowerpiercers was identified as Andean, with a single dispersal event from the northern Andes to Central America and a single dispersal event from the northern Andes to the tepuis. The first principal component, representing a contrast between hook size and bill size, was mapped onto the phylogeny to examine the evolution of relative hook size in the group. Across the phylogeny, a relatively large hook and a relatively small hook evolved multiple times in unrelated lineages, indicating lability in bill morphology. Differences in hook size among sympatric species, together with habitat partitioning and behavioural differences, can explain the coexistence of multiple species of flowerpiercers at the same locality. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 14,28. [source] Sugar Preferences in Nectar- and Fruit-Eating Birds: Behavioral Patterns and Physiological Causes,BIOTROPICA, Issue 1 2006Chris N. Lotz ABSTRACT Sucrose, glucose, and fructose are the three sugars that commonly occur in floral nectar and fruit pulp. The relative proportions of these three sugars in nectar and fruit in relation to the sugar preferences of pollinators and seed dispersers have received considerable attention. Based on the research of Herbert and Irene Baker and their collaborators, a dichotomy between sucrose-dominant hummingbird-pollinated flowers and hexose-dominant passerine flowers and fruits was proposed. Data on sugar preferences of several hummingbird species (which prefer sucrose) vs. a smaller sample of passerines (which prefer hexoses) neatly fitted this apparent dichotomy. This hummingbird,passerine dichotomy was strongly emphasized until the discovery of South African plants with sucrose-dominant nectars, which are pollinated by passerines that are able to digest, and prefer sucrose. Now we know that, with the exception of two clades, most passerines are able to assimilate sucrose. Most sugar preference studies have been conducted using a single, relatively high, sugar concentration in the nectar (ca 20%). Thus, we lack information about the role that sugar concentration might play in sugar selection. Because many digestive traits are strongly affected not only by sugar composition, but also by sugar concentration, we suggest that preferences for different sugar compositions are concentration-dependent. Indeed, recent studies on several unrelated nectar-feeding birds have found a distinct switch from hexose preference at low concentrations to sucrose preference at higher concentrations. Finally, we present some hypotheses about the role that birds could have played in molding the sugar composition of plant rewards. RESUMEN Sacarosa, glucosa y fructosa son los azúcares mas comunes en néctar floral y pulpa de fruta. La proporción relativa de estos azúcares en néctar floral y la pulpa de fruta han sido estudiadas en relación a las preferencias de azúcar de polinizadores y dispersores de semillas. Basandose en estudios de Herbert e Irene Baker y colaboradores se propuso la existencia de una dicotomía entre plantas con néctares ricos en sacarosa que son polinizadas por colibríes, y plantas con néctares y frutos ricos en hexosas que son polinizadas por paserinos. Datos sobre la preferencia de azúcares en varias especies de colibríes (que prefieren sacarosas) comparados con una pequeña muestra de paserinos (que prefieren hexosas) apoyan la existencia de la dicotomía propuesta. La dicotomía colibrí-paserino fue enfatizada por más de una década, hasta el descubrimiento de plantas sudafricanas con néctares ricos en sacarosa que son polinizadas por paserinos que prefieren sacarosa. Hoy sabemos que la mayoría de los paserinos, salvo los miembros de dos clados, pueden asimilar la sacarosa. La mayoría de los estudios sobre preferencias de azúcares han sido conducidos usando una sola concentración de azúcares en el néctar (ca 20%). Por lo tanto, carecemos de información sobre el papel que juega la concentración de azúcares en las preferencias de estos por las aves. Debido a que muchos procesos digestivos son afectados, no solo por la composición de azúcares, sino también por su concentración, sugerimos que las preferencias por diferentes azúcares dependerán de su concentración. Efectivamente, estudios recientes indican que diferentes aves prefieren alimentarse de hexosas a bajas concentraciones, y de sacarosa a altas concentraciones. Finalmente, presentamos algunas hipótesis sobre el papel que las aves pudieron haber tenido en la evolución de la composición de azúcares del néctar y la fruta que consumen. [source] Analysis of amino acids in nectar from Silene colorata Poiret (Caryophyllaceae)BOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2007ANASS TERRAB Nectar samples were collected from Silene colorata Poiret (Caryophyllaceae), in three different populations from south-western Spain: Zahara de la Sierra (Cádiz), Bornos (Cádiz) and Bormujos (Seville). Samples were analysed for amino acids by reverse-phase high-performance liquid chromatography with precolumn phenylisotiocyanate (PITC) derivatization. The method has the advantage of being highly sensitive, capable of detecting nanogram (ng) quantities of amino acids. Eighteen amino acids were identified and quantified. The mean number of amino acids in a nectar sample was 14 (SD = 2.8). Six amino acids (threonine, alanine, arginine, proline, tyrosine and methionine) were detected in all samples, accounting for 83% of the total amino acids content; proline and arginine were the most abundant amino acids, accounting for 40% and 20% of the total amino acids, respectively. The mean amounts of amino acids in nectar samples per population were 824, 782 and 356 µm in Zahara de la Sierra, Bornos and Bormujos, respectively. Environmental variations such as temperature and sunlight are factors influencing the metabolic processes of nectar production. Our results may contradict the theory that the chemical constituents of floral nectar vary according to the kinds of pollinators. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 155, 49,56. [source] The role of nectar production, flower pigments and odour in the pollination of four species of Passiflora (Passifloraceae) in south-eastern BrazilBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2001ISABELA GALARDA VARASSIN The pollination biology of four species of passionflower was studied in south-eastern Brazil, specifically the importance of chemical features of floral nectar, pigments and odours. All species required pollinators to produce fruits: P. alata was pollinated by bees, P. speciosa by hummingbirds, and P. galbana and P. mucronata by bats. Pollinators consumed nectar as a food source. The activity of vertebrate pollinators reflected resource availability: they foraged when large amounts of nectar were available and when quantitative resource predictability was greater. The nectar of the vertebrate-pollinated species was richer in cholesterol and phospholipids, and had a potassium-sodium ratio higher than 1.0. For all species, the light absorption of flowers was paralleled by the pollinators' visual spectral sensitivity. This first report on Passiflora floral volatile compounds showed that there was a greater chemical class diversity among the species pollinated by animals with an acute olfactory sense, such as bees and bats. Benzenoid alcohols were the most represented compounds. The fragrances contained compounds that occur in other plant species and in the exocrine secretions of bees. This study shows a strong association between pollinators and the attracting and rewarding features of flowers. [source] | ||||||||||