A CELLULOSE-HYDROLYZING FACTOR IN APHID SALIVA

Abstract

Fifty-eight species of aphids from a wide range of host plants, one leafhopper species from Vitis sp., and a psyllid from Alnus rugosa have been examined for their salivary ability to hydrolyse carboxymethyl cellulose (CMC) substrates. Most of these insects, when allowed to probe and secrete saliva into CMC-filled parafilm "sachets", reduced the CMC to glucose and sometimes to glucose and cellobiose. The presence of this cellulose-hydrolyzing factor varied among species, and within species according to morph, season, and host plant from which the insect culture had been derived. The behavior of the insects on the sachets resembled the characteristic "test probing" of aphids described by many authors. It is suggested that salivary components secreted during such test probes play a role in host plant selection and subsequent exploitation.