Leptinotarsa decemlineata(Say) from the central Mexican state of Morelos was studied to see whether exposure toSolanum tuberosumL. in the egg, larval, pupal, or adult stages would induce feeding.S. tuberosumis not native in the range ofL. decemlineatain Morelos and is rejected as food by Morelos larvae. No evidence was found for induction of feeding on potato when the parents had been fed potato in their larval stage, nor did the percentage of Morelos first instars feeding on potato increase after exposure of eggs or newly hatched larvae to potato. There was no difference in pupal weight between larvae that fed on potato and those that would feed only on the native host,Solanum angustifoliumMill., but first-instar mortality was 18.9% higher on potato. Neither encasement of Morelos pupae with pupal exuvia ofL. decemlineatafrom Rhode Island nor preovipositional feeding significantly affected larval feeding in the next generation. Larval feeding on potato was induced when Morelos larvae were exposed to potato frequently in earlier instars. This induction was independent of larval age. Previous feeding as larvae or preovipositional feeding increased feeding on potato by mature adults.