Quantitative Changes in Principal Wood Components During Digestion in Grubs of Anomala polita Blanch and Xylotrupes Gideon Linn. (Coleoptera: Scarabaeidae)

Consumption and assimilation of wood (food) and principal wood components in two species of scarabaeid grubs were investigated under laboratory conditions with different food. The rate of food consumption (dry weight of food/wet weight of grub) was 42.0-339.0 mg/gm grub/day (Digestion Co-efficient 16.6-19.0%) in Anomala polita Blanch, and 29.0-74.6 mg (D.C. 12.6-19.0%) in Xylotrupes gideon Linn. Among major wood components, digestion of the cellulose and the hemicelluloses group per gm food ingested ranged from 7.2-41.5 mg and 32.0-68.5 mg in A. polita and 4.4-29.8 mg and 25.8-94.3 mg in X. Gideon respectively. Digestion of lignin in A. polita varied from 54.4-116.5 mg (D.C. 13.5-21.0%) and in X. Gideon, 47.0-150.0 mg (D.C. 12.6-24.9%). The grubs have shown preference to digest the hemicelluloses group than the cellulose and the oligosaccharides.