Population and feeding capacity of dragonflies on insect pests of rice in Pakistan (Anisoptera: Libellulidae)

The quantity of rice pests consumed by 4 spp. in a day (12 h) was determined by forced feeding. Adult Orthetrum sabina devoured, on an average, 4.8, 4.2, 5.1, 3.8, 32.1 and 68.0, Crocothemis s. servilia 3.9,3.4,4.0, 3.0,20.3 and 39.0, C. erythraea3.5,3.0,3.8,2.7,15.2 and 22.8 while Pantala flavescens 2.9, 2.6, 3.3, 2.2, 9.1 and 15.2 white stem-borers (Scirpophaga innotata) , yellow stem-borers (S. incertulas), leaf-folders (Cnaphalocrocis medinalis), white leafhoppers (Cofana spectra), green leafhoppers (Nephotettix spp.) and white-backed planthoppers (Sogatella furcifera), respectively. The 9 $ of all the species consumed higher number of pests as compared with their 6 <J. The number of insect pests taken by each sp. ranked in the following order according to the size of insects: C. spectra < S. incertulas < S. innotata < C. medinalis < Nephotettix sp. < S. furcifera.