Chromosomal studies on gall aphids Eriosoma ulmi and Tetraneura nigriabdominalis from Kullu, Himachal Pradesh

Abstract

In the present investigation, karyotypes of two species of gall forming aphids, viz., Eriosoma ulmi (Linnaeus), and Tetraneura nigriabdominalis (Sasaki) have been studied. These aphid species were found to be infesting Ulmus wallichiana from Kullu district of Himachal Pradesh. The diploid chromosome number in E. ulmi is ten (2n=10), whereas T. nigriabdominalis is eighteen (2n=18). The chromosomes were holocentric. The karyotypes have been described. Idiograms were prepared on relative length data.