Thirty specimens from two colonies of Azteca trigona collected in Ponte Nova (20°25'S, 42°54'W ) and Viçosa (20°45'S, 42°52'W ), MG, Brazil were analyzed. The colonies were collected in the field and transferred to a plastic container and maintained in a BOD (Biochemical Oxygen Demand) incubator at 25°C following the protocol described by Cardoso et al. (2011) and fed with honey in order to obtain larvae in the pre-pupa stage (post-defecating larvae). The specimens were identified by specialists and Vouchers of the samples collected in this work were deposited in CEPLAC and MZUSP.
Cytogenetic analysis was performed using cerebral ganglia of the larvae selected. Metaphase chromosomes were obtained according to the methodology proposed by Imai et al. (1988) (link). Preparations obtained from fifteen individuals per colony were analyzed. The preparations were stained with Giemsa diluted in Sörensen buffer at (4%) for 20 minutes. On average, ten metaphases were analyzed per slide and ten slides were submitted to banding techniques. C-banding was performed by BSG method (Barium hydroxide/Saline/Giemsa) according to Sumner (1972) (link). The protocol of Schweizer (1980) (link) was used for preparation of sequential fluorochrome staining (CMA3/DA/DAPI). Identification of nucleolus organizer regions (NOR) was performed according to Howell and Black (1980) (link). The best metaphases were photographed using an Olympus BX60 microscope equipped with a camera Q color 3 Olympus®. Brightness and contrast of the karyotypes were optimized using Photoshop CS4. The karyotypes were mounted in Corel Draw® 13 image editing software. Karyotype structure was described according to the nomenclature proposed by Imai (1991) (link) and Levan et al. (1964) . For mounting of the karyotypes, the chromosomes were sorted into three groups: metacentric chromosomes (M), acrocentric chromosomes (A) with heterochromatin located across the length of the short arm of the chromosomes, and pseudo-acrocentric chromosomes (AM) which possess a long heterochromatic arm (Imai 1991 (link)).
Cytogenetic analysis was performed using cerebral ganglia of the larvae selected. Metaphase chromosomes were obtained according to the methodology proposed by Imai et al. (1988) (link). Preparations obtained from fifteen individuals per colony were analyzed. The preparations were stained with Giemsa diluted in Sörensen buffer at (4%) for 20 minutes. On average, ten metaphases were analyzed per slide and ten slides were submitted to banding techniques. C-banding was performed by BSG method (Barium hydroxide/Saline/Giemsa) according to Sumner (1972) (link). The protocol of Schweizer (1980) (link) was used for preparation of sequential fluorochrome staining (CMA3/DA/DAPI). Identification of nucleolus organizer regions (NOR) was performed according to Howell and Black (1980) (link). The best metaphases were photographed using an Olympus BX60 microscope equipped with a camera Q color 3 Olympus®. Brightness and contrast of the karyotypes were optimized using Photoshop CS4. The karyotypes were mounted in Corel Draw® 13 image editing software. Karyotype structure was described according to the nomenclature proposed by Imai (1991) (link) and Levan et al. (1964) . For mounting of the karyotypes, the chromosomes were sorted into three groups: metacentric chromosomes (M), acrocentric chromosomes (A) with heterochromatin located across the length of the short arm of the chromosomes, and pseudo-acrocentric chromosomes (AM) which possess a long heterochromatic arm (Imai 1991 (link)).
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