Diversity and abundance of insect visitors/pollinators on different genotypes of Brassica spp.

Abstract

Studies on diversity and abundance of insect pollinators on different cultivar of Brassica spp. were carried out and found eighteen bee species belonging to twelve families of five different orders were recorded visiting on the flowers of rapeseed-mustard genotypes. Order Hymenoptera contributed maximum diversity of pollinators followed by Diptera, Lepidoptera, Hemiptera and Coleoptera. Among hymenopterans, honey bees, Apis cerana F., Apis mellifera L., Apis florea F. and Apis dorsata F. were the most frequent visitors and in genotypes TH 68 and HNS 0901 experienced highest diversity. A. mellifera was most abundant during different day hours (1000. 1200. 1400 and 1600 h) among different Apis spp. on all genotypes. A. mellifera, A. cerana and A. florea population was found maximum in variety TH 68 whereas A. dorsata was most abundant on BSH-1 and HC-212. The mean densities of A. mellifera was maximum followed by A. cerana, A. dorsata and A. florea. A. florea was most abundant on variety TH 68 and genotype HC-212 (9.93 and 9.07 bees/m2/10 min respectively).