Revisiting the karyotype of the social wasp Polistes canadensis (Linnaeus, 1758) (Hymenoptera: Vespidae: Polistinae)

Abstract

Cytogenetic techniques have been improving over the last decades, providing useful information for the systematics and evolution of several groups, such as social insects. On the other hand, karyotypic data are still incipient for most wasp genera. For instance, only five of the 240 species of Polistes have been karyotyped, usually based on obsolete data. Therefore, this study aimed to revisit the karyotype structure of Polistes canadensis, providing unpublished information based on traditional (karyotyping and C-banding) and refined (GC- and AT-rich sites by base-specific fluorochrome staining) cytogenetic methods. Males and females of P. canadensis were characterized by haploid and diploid numbers of n = 28 and 2n = 56, respectively. The karyotype formula was established in 2K = 18M + 22SM + 16A with a predominance of pericentromeric heterochromatin and terminal GC+ sites in 16 chromosome pairs. Our results differ significantly from the previous karyotype reported for this species, probably related to the utilization of suitable methods of obtaining mitotic chromosomes in the present study. In addition, the detailed analysis of chromosomal microstructure provided potential cytotaxonomic markers for systematic inferences in social wasps.