Revisiting the Karyotype of the Social Wasp Polistes canadensis (Linnaeus, 1758) (Hymenoptera: Vespidae: Polistinae)

Abstract

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 21 out of the 242 species of Polistes were karyotyped, generally with data restricted to number and morphology. Therefore, this study aimed to revisit the karyotype structure of Polistes canadensis, providing unpublished information based on traditional cytogenetic methods (karyotyping, C-banding and base-specific fluorochrome staining). 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. These data suggest that fissions and inversions may be involved in the group karyoevolution. It should be pointed out that our results differ significantly from the first cytogenetic report in this species, which may be related to the outdated method of obtaining mitotic chromosomes or misidentification. As a matter of fact, the improved cytogenetic methods from the present study provided reliable information about the karyotype of P. canadensis that can be used in further comparative cytotaxonomic and evolutionary analyses of social wasps.

Keywords

• C-banding
• Chromosomes
• Cytogenetics
• Heterochromatin
• Polistini