Cytogenetic investigations on some species of the family reduviidae (insecta: hemiptera: heteroptera) from north India

Abstract

The suborder Heteroptera is very rich in terms of species diversity and includes more than 42,300 species distributed in 89 families. Reduviidae is the largest family of terrestrial predaceous heteropterans comprising 961 genera and 6601 species. It is characterized by the presence of relatively high chromosome number (12-34), simple and multiple sex mechanisms with X multiplicity and a definite metaphase-II arrangement. Cytogenetic data for Reduviidae pertains to 153 species belonging to 11 subfamilies worldwide which include 42 species from India. Keeping in mind the economic importance and scarcity of knowledge on cytogenetic aspects of this family, the present study was undertaken to carry out comprehensive work on reduviid bugs to study diploid chromosomal complement, sex mechanism, meiosis, location and base composition of C heterochromatin. Finally attempts have been made to find out cytological markers, if any. As many as 33 species belonging to 19 genera and referable to 4 subfamilies have been collected which include 17 of Harpactorinae, 7 of Stenopodainae, 4 of Peiratinae and 5 of Reduviinae. For cytogenetic investigations, air-dried slides were stained with Carbol-fuchsin to study normal chromosomal complement, with Giemsa stain to study C-banding patterns and with fluorescent dyes DAPI and CMA3 to study sequence specificity of the heterochromatic regions. Out of total 33 species, 25 species have been investigated for the first time for chromosome number and meiotic studies and thus are new to the cytogenetic world. 21 species have been subjected to Cbanding and 18 to fluorescent staining, all new for such a study. The significant results pertaining to each subfamily are summarized as follows: Harpactorinae: Out of 17 species, 13 are new to the cytogenetic world. Thirteen species have 2n=28=24A+X1X2X3Y, 3 have 2n=27=24A+X1X2Y and 1 has 2n=12=10A+XY. Out of 17, 16 species show multiplicity of X. Y is strikingly large and Xs are very small, similar or dissimilar in size.