Differential utilization of nutrients during development by the xylophagous leafhopper, Homalodisca coagulata

Abstract

Utilization of nutrients at different stages of development was examined for the xylophage, Homalodisca coagulata (Say). Survivorship and consumption rates of second‐instar, fourth‐instar and adult leafhoppers were measured daily on the hosts Lagerstroemia indica L. and Euonymus japonica Thumb. Rates of consumption, assimilation efficiencies and daily assimilation of nitrogen, carbon, and individual organic compounds were calculated based on chemical analyses of xylem fluid and insect excreta. Gross growth efficiencies of diet utilization were also estimated by comparing biomass of young adults to estimates of nutrient utilization of the two host species. Different instars survived and utilized nutrients at varying rates on the two hosts. Second‐instar leafhoppers survived at higher rates and utilized nitrogen more efficiently on E. japonica than on L. indica. However, assimilated nitrogen was much less as a result of lower consumption rates. In contrast, adults on L. indica had increased longevity, utilized carbon more efficiently, and assimilated higher quantities of both carbon and nitrogen than those on E. japonica. Efficiencies of nutrient utilization were high for H. coagulata compared to folivores or phloem feeders, particularly in the conversion of ingested nutrients to assimilated compounds. Variations in diet utilization during development are discussed in terms of polyphagy.

Alternation of host plants as a survival mechanism of leafhoppers Dilobopterus costalimai and Oncometopia facialis (Hemiptera: Cicadellidae), vectors of the Citrus Variegated Chlorosis (CVC)

“…Therefore, O. facialis nymphs manage to feed and develop on citrus seedlings, unlike the D. costalimai nymphs. Although it is not the goal of this study to quantify the hosts under the nutritional point of view, specific chemical compounds, as the amino acid, for instance, are likely to be present in the "falso boldo" plant, ensuring a better development for leafhopper nymphs as observed for the Homalodisca coagulata nymphs that need a distinguished feeding with amino acids, found in different hosts in order to develop (Brodbeck et al, 1990;1995).…”

“…For species Homalodisca coagulata the selection of host plants and the adult population were verified to be positively correlated with the concentration of a few amino acids found in standard plants regarding feeding, and the nymphs failed to develop successfully on the hosts preferred by the adults due to the fact that they cannot assimilate as efficiently as the adults the essential nutrients in nutritionally unbalanced plants (Brodbeck et al 1990;1995).…”

Effects of total dietary nitrogen and nitrogen form on the development of xylophagous leafhoppers

“…Carbohydrates were quantified using ion exchange chromatography with a Dionex-Ion-Pac column and a Dionex Pulse Amperometric Detector (Dionex Corp., Sunnyvale, CA) (Brodbeck et al, 1993(Brodbeck et al, , 1995. Organic acids and ureides were analyzed by cation exchange chromatography (Brodbeck et al, 1995(Brodbeck et al, , 1996. Concentrations of ammonia in insect exudate were quantified with a ion selective electrode (Brodbeck et al, 1996).…”

“…Seasonal changes in host selection are discrete, repeatable from year to year, and correlated with amide concentrations in xylem fluid of host plants (Brodbeck et al, 1990). Less is known about the host range for developing H. coagulata, although it has been established that nymphs cannot develop successfully on many of the hosts that are preferred by adults (Brodbeck et al, 1995(Brodbeck et al, ,1996. These studies established that H. coagulata nymphs are much less efficient at assimilating unbalanced profiles.…”

“…Briefly, amino acids were quantified after precolumn derivitization with phenylisothiocyanate and separation on a Pico Tag column (Waters Division, Millipore Corp., Milliford, MA) (Heinrickson and Meridith, 1984;Andersen et al, 1989Andersen et al, , 1992. Carbohydrates were quantified using ion exchange chromatography with a Dionex-Ion-Pac column and a Dionex Pulse Amperometric Detector (Dionex Corp., Sunnyvale, CA) (Brodbeck et al, 1993(Brodbeck et al, , 1995. Organic acids and ureides were analyzed by cation exchange chromatography (Brodbeck et al, 1995(Brodbeck et al, , 1996.…”