Estudio citogenético en dos poblaciones naturales de Doru lineare (Dermaptera, Forficulidae)

Abstract

Insects of the order Dermaptera, usually called earwigs, are widely distri- buted in America. Their feeding habits allow them to be associated with economically impor- tant crops. Doru lineare (Eschs.) is a predator of eggs and immature stages of many Lepi- doptera and leafhoppers (Hemiptera), pests of cotton, sugar cane and corn plantations. Pre- vious cytogenetic studies of the order are scarce, but they confirm the presence of holokine- tic chromosomes. The chromosome numbers vary from 2n = 7 ( Arixenia esau ) to 2n = 60 ( Hemimerus bouvieri ). In this paper the chromosome complement and the meiotic behavior in two natural populations of Doru lineare from Tucumán (The Argentine Republic) are exposed. The male diploid chromosome number is 20 (2n = 18 + XY), the chromosomes lack a pri- mary constriction (holokinetic) and they show a regular behavior during meiotic division (pre- reductional meiosis). Non-homologous chromosomes can establish non-chiasmatic associations between them during the course of meiosis. The fact that, a single individual from one of the populations exhibited serious irregularities in spermatogonial mitosis and meiosis, was empha- sized.