Influence of Food Plants on Growth and Development of Chrotogonus trachypterus Blanchard

Laboratory  experiments  were  conducted  with  the  surface  grasshopper,  Chrotogonus trachypterus, to evaluate the effect of food plants on its growth and development. As indicated by a growth index for hoppers, in descending order of effectiveness were; lucerne, wheat, barley,    mixed  food,  oats,  chickpea,  bermuda  grass,  spinach,  nut  grass  and  pigweed.  On lucerne, hoppers took the shortest period (17.40 days) to develop into a fledglings, while on pigweed, development took the longest (25.25 days). Hoppers had 100 per cent survival on lucerne,  wheat  and  barley;  survival  was  lowest  when  reared  on  pigweed:  82.50,  72.50  and 67.50  per  cent  for  hopper  survival  of  the  IV th ,  V th   and  VI th  instars  respectively).  However, irrespective of the food plant, the sixth instar hoppers developed into fledglings, showing a cent (emergence the 100 per cent adult) per cent survival. The effect of different food plants on food utilization indices evinced that efficiency of conversion of ingested food (ECI) was
high  when  the  hoppers  were  reared  either  on  wheat  (36.53%)  or  mixed  food  (35.20%),  but pigweed (16.21%) followed by nut grass (19.28) had lowest ECI. The approximate digestibility (AD) was high when the hoppers were reared on lucerne (45.20%) and significantly low in gram (38.39%). The efficacy of conversion of digested food (ECD) into body substances was significantly the maximum for hoppers raised on wheat (89.50%) and was significantly the lowest for hoppers on pigweed (42.14%).