Effect of food plants on the growth rate and survivability of Hieroglyphus banian(Fabricius)(Orthoptera: Acridoidea), a major paddy pest in India.

Abstract

Hieroglyphus banian (Fabricius) is a major agricultural pest of paddy fields in tropical and subtropical countries. Although, this species consumes a wide variety of food plants from different families, the families Poaceae and Cyperaceae were found to be the most preferred. Among plants belonging to these two families, Cynodon dactylon (Pers.), Oryza sativa (Lin.) and Cyperus kyllingia (Endl.) were highly suitable for H. banian growth. The growth rate of H. banian, in terms of the percentage of weight gain after feeding for 8 and 16-d after fledgling (0-d adult), was maximum (38.7% and 76%, respectively) when C. dactylon was used as their food and minimum (14.9% and 30.1%, respectively) when C. kyllingia was used, whereas, it was moderate (26% and 48%, respectively) on O. sativa. The approximate digestibility (AD) of C. dactylon was in the range of 87.9-89.5%, followed by O. sativa (86.5-88.6%) and C. kyllingia (85.5-86.9%). The efficiency of conversion of digested food to body tissue (ECD) varied from 1.7-2.2% after 8 d, whereas, it increased to 3.3-9.1% after 16 d from fledgling. The efficiency of conversion of ingested food to body tissue (ECI) varied from 1.4-2.0% after an 8 d period and it also increased to 2.9-4.1% after 16 d. The survivability of H. banian fed on these plants did not differ remarkably, although their survivability was higher on C. dactylon followed by O. sativa and C. kyllingia at any stage of their lifetime.