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Honeydew Production (honeydew + production)
Selected AbstractsSeparating host-tree and environmental determinants of honeydew production by Ultracoelostoma scale insects in a Nothofagus forestECOLOGICAL ENTOMOLOGY, Issue 4 2007ROGER J. DUNGAN Abstract 1.,Sugar-rich honeydew excreted (,produced') by insects feeding on phloem sap is a key energy flow in a range of temperate and tropical ecosystems. The present study measured honeydew produced by Ultracoelostoma sp. (Homoptera: Coelostomidiidae) scale insects feeding on Nothofagus solandri var. solandri (Hook f.) Oerst. trees in a temperate evergreen forest in New Zealand. Simultaneous measurements of environmental variables and canopy photosynthesis were conducted to allow separation of host-tree and environmental determinants of honeydew production. These relationships were further examined in experiments where canopy photosynthesis was manipulated by shading or plant nitrogen levels increased by foliar spray. 2.,Rates of honeydew production varied nine-fold from a maximum (± 1 SE) of 64.4 ± 15.2 mg dry mass m,2 bark h,1 in early summer (December) to a minimum of 7.4 ± 4.2 mg m,2 h,1 in winter (August). Rates of production measured 1.4 m from the base of the trees' stems varied significantly with stem diameter, and were higher on medium-sized (18 cm diameter) than small or large stems. 3.,Rates of production were significantly related to environmental conditions over the hours preceding measurement (air temperature and air saturation deficit averaged over the preceding 24 and 12 h respectively). There was no evidence that rates of production were directly related to short-term changes in the supply of carbohydrates from the canopy (either when compared with measurements of unmanipulated photosynthetic rate, or after sugar levels were manipulated by shading 80% of host-trees' leaf area), or to changes in phloem nitrogen content. 4.,The results show that there is no clear effect of host-tree carbon supply on honeydew production; if production is related to photosynthesis, the effect of this is much less important that the large and significant direct effect of environmental conditions on honeydew production. [source] Effect of cotton nitrogen fertilization on Bemisia argentifolii populations and honeydew productionENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 1 2001J.L. Bi Abstract The impact of nitrogen fertilization on cotton plants, Gossypium hirsutum L., silverleaf whitefly, Bemisia argentifolii Bellows & Perring, population dynamics and honeydew production were investigated in the field at Riverside, California, USA. Treatments were soil applications of 0, 112, 168 and 224 kg nitrogen per hectare, and a soil application of 112 kg of nitrogen plus a foliar application of 17 kg nitrogen per hectare. Increased numbers of both adult and immature whiteflies occurred during population peaks with increasing amounts of applied nitrogen. Higher numbers of whiteflies resulted in increased levels of honeydew. Increasing plant nitrogen also enhanced cotton foliar photosynthetic rates and stomatal conductance, and altered concentrations of glucose, fructose and sucrose in cotton petioles. However, at our treatment levels nitrogen had no effect on seedcotton yield. Petiole glucose levels were significantly correlated with numbers of whitefly adults on leaves during their peak populations. Significant correlations between whitefly numbers and other cotton physiological parameters occurred on only a few sampling dates. [source] Honeydew amino acids in relation to sugars and their role in the establishment of ant-attendance hierarchy in eight species of aphids feeding on tansy (Tanacetum vulgare)PHYSIOLOGICAL ENTOMOLOGY, Issue 4 2004J. Woodring Abstract., The ratio of the concentration of honeydew total amino acids to total sugars in the honeydew of eight species of aphids, all feeding on tansy, Tanacetum vulgare (L.), was determined and correlated with honeydew production and ant-attendance. The honeydew of the five ant-attended aphid species [Metopeurum fuscoviride (Stroyan), Trama troglodytes (v. Hayd), Aphis vandergooti (Börner), Brachycardus cardui (L.), Aphis fabae (Scopoli)] was rich in total amino acids, ranging from 12.9 to 20.8 nmol µL,1 compared with the unattended aphid Macrosiphoniella tanacetaria (Kalt.) with only 3 nmol µL,1. Asparagine, glutamine, glutamic acid and serine (all nonessential amino acids) were the predominant amino acids in the honeydew of all species. The total concentration of amino acids in the phloem sap of tansy was much higher (78.7 nmol µL,1) then in the honeydew samples, and the predominant amino acids were glutamate (34.3%) and threonine (17.7%). A somewhat unexpected result was the finding that those aphid species with the highest total amino acid concentration in the honeydew always had the highest concentration of sugars. The lowest amino acid,sugar combined value was 104,28.8 nmol µL,1 in the non ant-attended species M. tanacetaria, and the highest value was an average of 270,89.9 nmol µL,1 for the three most intensely attended aphid species M. fuscoviride, A. vandergooti and T. troglodytes. There is no evidence that any single amino acid or group of amino acids in the honeydew acted as an attractant for ant-attendance in these eight aphid species. The richness of the honeydew (rate of secretion × total concentration of sugars), along with the presence of the attractant sugar melezitose, comprised the critical factors determining the extent of ant-attendance of the aphids feeding on T. vulgare. The high total amino acid concentration in sugar-rich honeydews can be explained by the high flow-through of nutrients in aphids that are particularly well attended by ants. [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] | ||||||||||