RESUMO

Reports of Rhipicephalus microplus resistant populations worldwide have increased extensively, making it difficult to control this ectoparasite. The adult immersion test, commonly used to screen for acaricide resistance, produces the results only after 40 days of the tick collection because it needs the eggs to be laid and larvae to hatch. The present study aims to develop an automatic method, based on deep learning, to predict the hatching of R. microplus larva based on egg morphology. Initially, the time course of embryonic development of tick eggs was performed to discriminate between viable and non-viable eggs. Secondly, using artificial intelligence deep learning techniques, a method was developed to classify and count the eggs. The larval hatching rate of three populations of R. microplus was evaluated for the software validation process. Groups of three and six images of eggs with 12 days of embryonic development were submitted to the software to predict the larval hatching percent automatically. The results obtained by the software were compared with the prediction results of the hatching percentage performed manually by the specialist and with the results of the hatching percentage of larvae obtained in the biological assay. The group with three images of each population submitted to the software for automatic prediction of the larval hatching percent presented mean values of 96.35% ± 3.33 (Piracanjuba population), 95.98% ± 3.5 (Desterro population) and 0.0% ± 0.0 (Barbalha population). For groups with six images, the values were 94.41% ± 3.84 (Piracanjuba population), 95.93% ± 2.36 (Desterro population) and 0.0% ± 0.0 (Barbalha population). Biological assays showed the following hatching percentage values: 98% ± 1.73 (Piracanjuba population); 96% ± 2.1 (Desterro population); and 0.14% ± 0.25 (Barbalha population). There was no statistical difference between the evaluated methods. The automatic method for predicting the hatching percentage of R. microplus larvae was validated and proved to be effective, with considerable reduction in time to obtain results.

Assuntos

RESUMO

Zabrotes subfasciatus (Boh.) has been extensively studied in its agronomic and biochemical aspects due to its importance as a damaging insect to leguminous grains during storage. The few cytogenetic studies published on this species yielded conflicting results. In this study, the karyotype was analyzed in order to accurately describe the chromosome C-banding patterns and meiosis. The brain ganglion at the prepupa and the adult and pupal testes were analyzed. All individuals had 26 chromosomes in both brain ganglion and spermatogonic mitotic metaphases. These chromosomes were classified as follows: the 12th pair and the Y chromosome were telocentric; the X chromosome was acrocentric; the 4th and 5th pairs were submetacentric; and the remaining pairs were all metacentric. One of the members of the 5th pair presented a secondary constriction. All chromosomes presented pericentromeric heterochromatin. The large arms of the pairs 5, 9 and X presented heterochromatin. The X chromosome showed to be heteropyknotic throughout the prophase of the first meiotic division. The subphases of prophase I were atypical and meiosis II was rarely identified. Testes of all males showed a few cells; the bivalents were rod-like shaped in metaphase I. Karyological formulae were 2n = 24 + XX in females and 2n = 24 + XYp and either n = 12 + X or n = 12 + Y in males.

Assuntos

RESUMO

Zabrotes subfasciatus (Boh.) é estudada intensivamente em termos agronômicos e bioquímicos por causar danos aos grãos de leguminosas armazenados. No entanto, os dados publicados sobre o seu cariótipo são escassos e conflitantes. Assim, o objetivo deste estudo foi descrever o cariótipo e a meiose desse inseto e analisar o padrão de bandas-C de seus cromossomos. Foram analisados os gânglios cerebrais de pré-pupas e os testículos de adultos e pupas com adaptação de uma técnica que permitiu boa qualidade de preparo dos cromossomos dessa espécie. Todos os indivíduos apresentaram 26 cromossomos nas metáfases mitóticas. Esses cromossomos foram classificados em: acrocêntricos (cromossomo X); submetacêntricos (pares 4 e 5); subtelocêntricos (par 12 e cromossomo y); metacêntricos (demais pares). O cromossomo 5 apresentou uma constrição secundária. Todos os cromossomos apresentaram heterocromatina próximo ao centrômero e os cromossomos 5, 9 e X, nos braços longos. O cromossomo X mostrou-se heteropicnótico durante toda a prófase da primeira divisão meiótica. As subfases da prófase I foram pouco distintas e a meiose II de difícil identificação. Os testículos de todos os machos apresentaram poucas células. Os bivalentes apresentaram a forma de bastão na metáfase I. O seu cariótipo constitui-se de 26 cromossomos, sendo as fórmulas cariotípicas 2n = 24 + XX nas fêmeas e 2n = 24 + Xyp e n = 12 + X ou n = 12 + y nos machos.

Zabrotes subfasciatus (Boh.) has been extensively studied in its agronomic and biochemical aspects due to its importance as a damaging insect to leguminous grains during storage. The few cytogenetic studies published on this species yielded conflicting results. In this study, the karyotype was analyzed in order to accurately describe the chromosome C-banding patterns and meiosis. The brain ganglion at the prepupa and the adult and pupal testes were analyzed. All individuals had 26 chromosomes in both brain ganglion and spermatogonic mitotic metaphases. These chromosomes were classified as follows: the 12th pair and the Y chromosome were telocentric; the X chromosome was acrocentric; the 4th and 5th pairs were submetacentric; and the remaining pairs were all metacentric. One of the members of the 5th pair presented a secondary constriction. All chromosomes presented pericentromeric heterochromatin. The large arms of the pairs 5, 9 and X presented heterochromatin. The X chromosome showed to be heteropyknotic throughout the prophase of the first meiotic division. The subphases of prophase I were atypical and meiosis II was rarely identified. Testes of all males showed a few cells; the bivalents were rod-like shaped in metaphase I. Karyological formulae were 2n = 24 + XX in females and 2n = 24 + XYp and either n = 12 + X or n = 12 + Y in males.

Assuntos