Running title: Distribution of Anastrepha fraterculus complex

19 p.-7 fig.-4 tab.Three species of the Anastrepha fraterculuscomplex (AF complex) occur in eastern Brazil, namely Anastrepha sp.1aff. fraterculus, Anastrepha sp.2aff. fraterculus, and Anastrepha sp.3aff. fraterculus. Along their extensive distribution, which differs in relation to geographic topography, they present differences in the host fruit usage in some zones of sympatry. The dynamics underlying the extant distribution pattern of the three species of the AF complex in eastern Brazil was herein analysed by a novel application of the generalized logical formalism methodology. The present report illustrates that two factors, the uni-directional incompatibility between sp1and sp2, with the former overriding the second, besides a yet unknown environmental factor related to altitude, playan instructional role in the generation of the extant distribution pattern observed in nature. Simulations about temporal order of invasion of species in a given area showed that the outcome is independent of the order of arrival of the species. This kind of approach has also a potential to make predictions about the population dynamics after the introduction of species, or the eradication of species in a given area.The study was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo, Brazil (FAPESP2016/00782-7) to DS. LS received a financial support from the Coordenação de Aperfeiçoamento de Pessoal de Nivel Superior (CAPES/PROEX-2016) for a short stay at the Instituto de Biociências, Universidade de São Paulo, Brazil.Peer reviewe

Role of microtubules and microtubule organizing centers on meiotic chromosome elimination in Sciara ocellaris

Spindle formation and chromosome elimination during male meiosis in Sciara ocellaris (Diptera, Sciaridae) has been studied by immunofluorescence techniques. During meiosis I a monopolar spindle is formed from a single polar complex (centrosome-like structure). This single centrosomal structure persists during meiosis II and is responsible for the non-disjunction of the maternal X chromatids. During meiosis I and II non-spindle microtubules are assembled in the cytoplasmic bud regions of the spermatocytes. The chromosomes undergoing elimination during both meiotic divisions are segregated to the bud region where they associate with bundles of microtubules. The presence and distribution of centrosomal antigens in S. ocellaris meiotic spindles and bud regions has been investigated using different antibodies. gamma-Tubulin and centrin are present in the bud as well as in the single polar complex of first meiotic spindle. The results suggest that spermatocyte bud regions contain microtubule-organizing centres (MTOCs) that nucleate cytoplasmic microtubules that are involved in capturing chromosomes in the bud regions. The distribution of actin and myosin in the spermatocytes during meiosis is also reported.This work has been supported by a UE project C11*-CT94-0071

Cytological characterization of sex chromosomes and ribosomal DNA location in Anastrepha species (Diptera, Tephritidae)

This paper reports a comparative analysis of heterochromatin organization in the sex chromosomes of the fruit fly Anastrepha. Mitotic chromosomes of eight Anastrepha species from different taxonomic groups were stained with DAPI and chromomycin A3 fluorochromes followed by C-banding. A specific sex-chromosome banding pattern was obtained for each of the analyzed species. Fluorescence in situ hybridization (FISH) was performed to investigate the chromosomal location of rDNA loci. In all cases the rDNA sequences were found to localize exclusively to the sex chromosomes. The results further extend the chromosomal knowledge of Anastrepha and allow a precise species identification

The Gene doublesex of the Fruit Fly Anastrepha obliqua (Diptera, Tephritidae)

The gene doublesex of Anastrepha obliqua is composed of four instead of the usual six exons. It is transcribed in both sexes and its primary transcript undergoes sex-specific splicing, producing female Dsx(F) and male Dsx(M) proteins, which have in common the amino-terminal region but which differ at the carboxyl-terminal region

The gene transformer of anastrepha fruit flies (Diptera, tephritidae) and its evolution in insects.

In the tephritids Ceratitis capitata and Bactrocera oleae, the gene transformer acts as the memory device for sex determination, via an auto-regulatory function; and functional Tra protein is produced only in females. This paper investigates the evolution of the gene tra, which was characterised in twelve tephritid species belonging to the less extensively analysed genus Anastrepha. Our study provided the following major conclusions. Firstly, the memory device mechanism used by this gene in sex determination in tephritids likely existed in the common ancestor of the Ceratitis, Bactrocera and Anastrepha phylogenetic lineages. This mechanism would represent the ancestral state with respect to the extant cascade seen in the more evolved Drosophila lineage. Secondly, Transformer2-specific binding intronic splicing silencer sites were found in the splicing regulatory region of transformer but not in doublesex pre-mRNAs in these tephritids. Thus, these sites probably provide the discriminating feature for the putative dual splicing activity of the Tra-Tra2 complex in tephritids. It acts as a splicing activator in dsx pre-mRNA splicing (its binding to the female-specific exon promotes the inclusion of this exon into the mature mRNA), and as a splicing inhibitor in tra pre-mRNA splicing (its binding to the male-specific exons prevents the inclusion of these exons into the mature mRNA). Further, a highly conserved region was found in the specific amino-terminal region of the tephritid Tra protein that might be involved in Tra auto-regulatory function and hence in its repressive splicing behaviour. Finally, the Tra proteins conserved the SR dipeptides, which are essential for Tra functionality