Classic and molecular cytogenetic analysis unveils different chromosome rearrangements shaping the karyotype of Monobia angulosa Saussure, 1852 (Hymenoptera: Vespidae: Eumeninae)

Abstract

Abstract Cytogenetic molecular studies involving hymenopterans have improved our knowledge about the composition, organization and evolution of the genomes of these insects. However, few cytogenetic studies have been performed in solitary wasps Eumeninae, which represents the most diverse subfamily of Vespidae. In this study, we describe the karyotype of the wasp Monobia angulosa using conventional and molecular cytogenetic techniques, in order to contribute to the understanding of chromosomal variation in this solitary wasp. The results indicated an odd chromosome number of 2n = 27 in females and n = 14 in males. The heterochromatin was located in centromeric/pericentromeric regions, and also in short arms in females and males. Chromomycin A3 staining revealed four and two bright interstitial bands in females and males, respectively. One of these marks corresponded to 18S rDNA clusters in both females and males. The microsatellite (GA)15 was located exclusively in the euchromatic regions in females and males. These results allowed us to suggest the occurrence of different chromosomal rearrangements, such as duplication/deletion of heterochromatic and euchromatic segments due to unequal crossing-over and Robertsonian rearrangements, to explain the origin of the chromosomal variations detected in the karyotype of this species. The few molecular cytogenetic studies already performed with Eumeninae wasps have revealed extraordinary karyotypic plasticity in this insect group.