Effect of rutin on the neonate sensitivity, dietary utilization and mid-gut carboxylesterase activity ofSpodoptera litura (Fabricius) (Lepidoptera: Noctuidae)

Rutin (quercitin-3-β-D-rutinoside) a widely occurring plant glycoside affects neonate survival and inhibits early larval growth of the tobacco leaf eating caterpillar,Spodoptera litura (F) when added to an artificial diet for this insect. Dietary concentration of rutin up to 1% wet weight had no adverse effect on the weight gain, nutritional indices (approximate digestibility, efficiency of conversion of assimilated and ingested food) when fed to early V instar larvae over a period of 48 h. Rutin was excreted unchanged and the overall amount excreted was ≈50%. Neonate larvae reared on control diet till early V instar and subsequently fed on high doses (0·1 to 1%) of rutin did not exhibit any increase in the mid-gut carboxylesterase activity. Similar rearing on sublethal doses (0·01 to 0·1%) of rutin, followed by feeding of a high dose (1%), resulted in significant increase in the midgut carboxylesterase activity of V instar larvae.