Asymmetry of the frontal bristles and postocular setae was studied in samples from natural populations and laboratory colonies of Anastrepha sp. 1 aff. fraterculus, of A. sp. 2 aff. fraterculus, and in F1 hybrids obtained from laboratory reciprocal crosses. Natural populations were sampled in a zone of sympatry and in two geographically distant regions with different climatic conditions. Asymmetry was scored as the differences between the number of bristles and of setae on the right and left sides of the head, males and females analyzed independently. The two traits exhibited variability according to the model of fluctuating asymmetry (FA). No significant differences among samples were found in the FA of frontal bristles. A significant FA was observed for the postocular setae of A. sp. 1 males from a southern population (Vacaria, RS) as compared to the asymmetry exhibited by males and females of some other samples. No significant differences in FA were observed among the interspecific hybrids and the laboratory samples of both parental species. The higher FA found in the males from Vacaria was attributed to climatic conditions prevailing in that region. The absence of a higher FA in hybrids may be related to the relatively recent evolutionary history of the two species.

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.

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.

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.

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.

A morfologia dos ovos de Anastrepha sp.2 aff. fraterculus foi avaliada em amostras de ovaríolos maduros obtidos de fêmeas preservadas em etanol, de fêmeas recém-mortas e comparada com a de ovos recém-depositados. As características da ornamentação do córion, assim como da estrutura interna dos ovos recém-depositados também puderam ser observadas nos ovos dissecados das fêmeas. Fêmeas preservadas em etanol podem ser utilizadas para análise da morfologia dos ovos, possibilitando a inclusão de espécies, cujos ovos não são obtidos facilmente, nesse tipo de análise.

Features of eggshell morphology in Anastrepha sp.2 aff. fraterculus were evaluated in mature ovariole ova dissected from females preserved in ethanol, and from ovaries of fresh killed females in comparison to that of freshly laid eggs. The characteristics of sculpturing as well as of internal structure of the chorion in oviposited eggs could be observed in both samples of mature ovariole ova. Ethanol preserved females may be used as a source of eggs for morphological studies allowing this kind of analysis to species whose eggs are not readily obtained.

Neste trabalho foram avaliados alguns aspectos do isolamento reprodutivo entre populações alopátricas de duas espécies do complexo Anastrepha fraterculus (A. fraterculus sp. 1 e sp. 2) em condições de laboratório. A maioria dos cruzamentos intraespecíficos, assim como aqueles entre fêmeas da sp. 2 e machos de sp. 1, foram férteis. No cruzamento recíproco, somente 41.7% resultaram em progênies viáveis. A taxa de eclosão das larvas foi similar para as duas espécies, mas significativamente menor para os cruzamentos interespecíficos. A proporção sexual da progênie adulta foi de 1:1 tanto nos cruzamentos intraespecíficos quanto naqueles de fêmeas de sp. 1 com machos de sp. 2. Entretanto, nos cruzamentos entre fêmeas de sp. 2 com machos de sp. 1 houve um desvio significativo na proporção sexual das progênies, com um excesso de fêmeas. Esta observação está de acordo com a regra de Haldane, cuja ocorrência reflete a existência de isolamento reprodutivo pós-zigótico. Os resultados reforçam a sugestão da existência de dois taxa distintos em A. fraterculus.

Some aspects of reproductive isolation between allopatric populations of two closely related species of the Anastrepha fraterculus complex (A. fraterculus sp. 1 and sp. 2) were evaluated in laboratory conditions. Most of the crosses were fertile in each species as well as between sp. 2 females and sp. 1 males. In the reciprocal cross only 41.7% of the matings yielded viable progeny. Egg hatching occurred at similar rates within the two species, but was significantly lower in the crosses between the species. Adult emergence did not differ significantly among crosses. The sex ratio of adult progeny within each species, as well as in the hybrid progeny derived from sp. 1 females crossed to sp. 2 males, did not differ from the expected 1:1 ratio. However, in the crosses between sp. 2 females to sp. 1 males, a significant deviation in the sex ratio in favor of females was observed, according to the Haldane's rule. The results reinforce previous data which indicated that A. fraterculus sp. 1 and A. fraterculus sp. 2 are distinct biological entities.