Effects of some Food Plants on the Growth, Development and Fecundity of Zonocerus variegatus (L)

Abstract

The performance of the variegated grasshopper, Zonocerus variegatus (L) fed on different food plants namely: cassava (Manihot esculenta), pawpaw (Carica papaya) and acalypha (Acalypha wilkesiana) and mixtures of these plants (mixed diets) from 5th nymphal instar to adult were investigated. Survivorship and longevity of nymphs and the reproductive performance of adult Zonocerus was greater and better for insect fed on cassava and mixed diets, as compared to those fed only on Acalypha and pawpaw. Adults emerged between the 5th-16th week in cages containing 5th instars fed on cassava and mixed diets, and between 7-23 weeks for those fed on acalypha and pawpaw. There were significant differences in the measurments of the body parameters of insects fed on the four different food plants (ANOVA P =0.05). Ranking was Cassava>Mixture>pawpaw>Acalyhpa. Sex had no significant effect on the measurement of body parameters irrespective of the food plants (ANOVA P >0.05). Feeding assay showed that cassava was the most preferred and most consumed food plant. This had a corresponding effect on the weight gained by the insects. The results of the proximate analysis showed significant differences in the dry matter, crude protein and fat content of Z. variegatus fed on the different food plants (ANOVA P> 0.05) . A positive correlation existed between the body weight and protein and fat content of Z. variegatus fed on the different food plants (R=0.99).