Concentration in thespringoffeedingbycaterpillars ofthewintermoth,OperophterabrumataL., and otherspeciesof Lepidopteraon oak treesin Englandis believedto
berelatedtoseasonalchangesinthetextureandchemicalcomposition oftheleaves. Increasing
leaftoughness is a proximate, thoughprobablynotultimate, factorpreventing latelarvalfeedingby thewintermoth,thecommonest springspecieson oak. Early feedingcoincideswith