Cytogenetic Analysis in Trigona spinipes Fabricius (Hymenoptera, Meliponina) Reveals Intraspecific Variation.

Trigona spinipes Fabricius is a stingless bee with wide geographical distribution. Although being sometimes considered an agricultural pest, in fact, it has great pollinating potential, and therefore economic interest. Conventional and molecular cytogenetic techniques have been little used to verify genetic diversity in this species, despite its potential to reveal information about the reorganization of the genome having been demonstrated in other species. Conventional cytogenetic techniques, fluorochrome staining, and fluorescent in situ hybridization with 18S rDNA, telomeric, and microsatellite probes (GA) were used in this study to characterize and compare T. spinipes from different locations. The karyotypes showed a conserved chromosome number 2n = 34; however, geographic variations were verified in the different features and cytogenetic techniques analyzed, such as karyotype formulas, fluorocrome staining, and FISH. Although the 18S rDNA probe revealed the same number of markings in five rDNA clusters, the chromosomal pairs containing these markers varied between studied locations. The probe for microsatellite (GA) also showed polymorphisms within this species. The results reveal that T. spinipes has many intraspecific differences, revealing a higher chromosomal variation than expected.