A CELLULOSE-HYDROLYZING FACTOR IN APHIDS

Abstract

Extracts of 12 species of aphids differed in their capacities to reduce the viscosity of methyl cellulose (MC) substrates. The activity of these extracts varied from as much as 60% reduction of viscosity in 48 hours, when the species Myzus cerasi Fab. from Prunus pennsylvanica L. was used, to zero change when the extracts were from Tuberolachnus salignus (Gmelin) from Salix babylonica L. Extracts from the remaining 10 species reduced the viscosity of MC substrates by about 25% in the same period. In many cases the activity of these extracts was almost doubled if the extract was heated in a boiling water bath for 5 minutes prior to being incubated with the MC; in only a few cases was it reduced. The plant host on which the aphids were cultured appeared to influence both the rate of activity and the effect of heating.