Cytogenetic determination of two species of lacewings (Neuroptera: Chrysopidae)

Abstract

Abstract The Chrysopidae family is the second most important family in the order Neuroptera. Chrysoperla externa and Chrysoperla argentina are two of the four chrysopid species of economic importance in Argentina. Meiotic studies of the species have indicated that have chromosome numbers of 2n = 12. The objective of this study was to analyze and describe the biology of C. externa and C. argentina chromosomes in terms of the cell cycle and karyotype because of the lack of exhaustive details of the karyotype or mitotic cycle of both species of lacewings. Chromosomes of C. externa were measured at the metaphase stage, C. argentina chromosomes were measured at the end of the mitotic prophase. Chromosomes that exhibited natural banding were paired together. Chromosomes that did not show marked differentiation were grouped according to the criterion of a similar chromosome contribution. The chromosomes are rod shaped without primary constriction with a gradual variation in size. In both species, sex chromosomes exhibited marked dimorphism. The X chromosome is among the largest chromosome pairs and the Y chromosome among the smallest. Chrysoperla externa shows natural chromosome banding that allows three of the six pairs that make up its genome to be distinguished. Chrysoperla argentina only two chromosome pairs exhibit natural banding. In conclusion, this study presents, for the first time, a proposal for nomenclature, identification of the chromosomes and kariotype of C. externa and C. argentina, accompanied by detailed information on their cell cycle.