Bv. Brodbeck et al., DIFFERENTIAL UTILIZATION OF NUTRIENTS DURING DEVELOPMENT BY THE XYLOPHAGOUS LEAFHOPPER, HOMALODISCA-COAGULATA, Entomologia experimentalis et applicata, 75(3), 1995, pp. 279-289
Utilization of nutrients at different stages of development was examin
ed for the xylophage, Homalodisca coagulata (Say). Survivorship and co
nsumption 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 da
ily 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 estim
ated by comparing biomass of young adults to estimates of nutrient uti
lization of the two host species. Different instars survived and utili
zed nutrients at varying rates on the two hosts. Second-instar leafhop
pers survived at higher rates and utilized nitrogen more efficiently o
n E. japonica than on L. indica. However, assimilated nitrogen was muc
h less as a result of lower consumption rates. In contrast, adults on
L. indica had increased longevity, utilized carbon more efficiently, a
nd assimilated higher quantities of both carbon and nitrogen than thos
e on E. japonica. Efficiencies of nutrient utilization were high for H
. coagulata compared to folivores or phloem feeders, particularly in t
he conversion of ingested nutrients to assimilated compounds. Variatio
ns in diet utilization during development are discussed in terms of po
lyphagy.