Karyotype relationships among Anastrepha bistrigata, A. striata and A. serpentina (Diptera, Tephritidae)

The species of Anastrepha are arranged into 17 intrageneric groups. Recently, it was proposed that two species of the striata group, Anastrepha striata and A. bistrigata, might be realocated to serpentina group. Anastrepha bistrigata and A. serpentina have an X1X2Y/X1X1 X2X2 sex chromosome system while A. striata has a XY/XX system. It was previously proposed that the karyotype of A. bistrigata could be derived from that of A. striata by an Y:A fusion, and that the karyotype of A. serpentina would be derived from another, hypothetical karyotype. In the present report sequential staining with DAPI and chromomycin A3 (CMA3), followed by C-banding, revealed that the C-banded heterochromatic blocks of the sex chromosomes of A. bistrigata have different affinities to fluorochromes in comparison to the chromosomes of A. striata, from which they have hypothetically derived. The chromosomes of A. serpentina show substantial differences in their cytochemical properties compared to their A. bistrigata and A. striata counterparts. The FISH technique showed that the ribosomal gene sequences are located in DAPI- or DAPI/CMA3-positive heterochromatic blocks of the sex chromosomes, one site on the Y chromosome and one site on the X chromosome (X1 in A. bistrigata and A. serpentina). The data suggest that the karyotype of A. striata and A. bistrigata could be derived from a common ancestral karyotype, while the A. serpentina karyotype probably has a distinct origin.

Occurrence of Wolbachia in Brazilian samples of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae)

Wolbachia bacteria were detected by PCR followed by sequencing of a fragment of the 16S ribosomal gene, in a natural population sample and in two laboratory colonies of the medfly, C. capitata (Wied.), from Brazil. Sequencing revealed that the fragment was compatible with the Wolbachia type A group found in several insect species. This is the first description of a natural Wolbachia infection in C. capitata, since several other samples from different regions so far analyzed seemed to be free of infection.

Bactérias Wolbachia foram detectadas por PCR seguido de seqüenciamento de um segmento do gene ribossomal 16S em uma amostra de população natural e em duas colônias de laboratório de Ceratitis capitata (Wied.) do Brasil. O seqüenciamento do fragmento amplificado mostrou que este é compatível com os de Wolbachia tipo A, encontrada em numerosas espécies de insetos. Esta é a primeira descrição de uma infecção natural desse hospedeiro por Wolbachia desde que, em linhagens de C. capitata provenientes de outras regiões, não foram encontradas essas bactérias.

Karyotype characterization of Anastrepha fruit flies (Diptera: Tephritidae)

The study comprises the description of the C-banded mitotic chromosomes of five species of Anastrepha, A. amita Zucchi, A. turpiniae Stone, A. zenildae Zucchi, A. grandis (Macquart) and A. leptozona Hendel , and a reanalysis of the chromosomes of three other species, A. distincta Greene, A. obliqua (Macquart) and A. sororcula Zucchi. The species have a diploid number of 12, while A. leptozona has 2n = 10. Heteromorphism of the sex chromosomes is present in all of the species, which have a XY/XX sex chromosome system. A. grandis and A. leptozona have meta and submetacentric autosomes while all of the chromosomes in the other species are acrocentric. The species can be characterized unequivocally by the length and the pattern of blocks of heterochromatin in the sex chromosomes.

O estudo apresenta a descrição dos cromossomos mitóticos, através do bandamento-C, de cinco espécies de Anastrepha, A. amita Zucchi, A. turpiniae Stone, A. zenildae Zucchi, A. grandis (Macquart) and A. leptozona Hendel e uma reanálise dos carótipos de três outras espécies, A. distincta Greene, A. obliqua (Macquart) and A. sororcula Zucchi, segundo a mesma técnica. As espécies apresentam número diplóide igual a 12 cromossomos, exceto A. leptozona com 2n = 10. Os cromossomos sexuais são heteromórficos e com sistema XX/XY. Os autossomos são meta ou submetacêntricos em A. grandis and A. leptozona e acrocêntricos nas demais espécies. Os cromossomos sexuais apresentam comprimento e padrão de blocos de heterocromatina característicos para cada espécie.