Morphological Variations in the Local Populations of the Soil Collembola Proisotoma (Clavisotoma) fitchioides (Denis 1947) (Insecta) in Kerala

Abstract

Morphological Variations in Priostoma(Clavisolonia) filchioides collected From Soils of two neighboring localities are presented. From A obtained from one locality was well pigmented while Form B from the other locality was poorly pigmented in comparison with the former. Variations exist in the mean body length and in the mean ratios, antennal length/head diagonal, trunk/tibiotarsus III, trunk/furcula, and manubrium dens + mucro. Application of ‘t’ test showed that while the difference in the mean body length between Form A and Form B was insignificant, the difference in the mean of the ratios was highly Significant. Together with the reduction in the pigmentation of the body a tendency for the reduction in the length of the appendages in relation to the body length and a reduction in the number of a setae in the trunk segments was noted in form B. The patchy distribution of the species was thought to be responsible for maintaining the kind of variations observed in the species studied.