Aedesaegypti: egg morphology and embryonic development

Durvanei Augusto Maria,Ana Paula Miranda Mundim-Pombo,Hianka Jasmyne Costa De Carvalho,Maria Angélica Miglino,Marisol León,Rafaela Rodrigues Ribeiro

doi:10.1186/s13071-021-05024-6

Durvanei Augusto Maria, Ana Paula Miranda Mundim-Pombo + Show 4 more

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https://doi.org/10.1186/s13071-021-05024-6

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Abstract

BackgroundThe diseases for which Aedes aegypti is a vector are worrisome. The high vector competence of this mosquito, as well as its anthropophilia and ability to adapt to the urban environment, allows it to exploit many habitats, making its prevention an arduous task. Despite current disease control measures focused on the mosquito, the effectiveness in containing its dispersion still requires improvement; thus greater knowledge about this insect is fundamental.MethodsAedes aegypti egg morphology and embryonic development were analyzed from eggs of the insectary of the Institute of Biomedical Sciences of the University of São Paulo. Optical (light and confocal) and electronic (transmission and scanning) microscopy were used to analyze the morphological and ultrastructural features of the eggs. Embryos were observed in the initial (0–20.5 h after egg-laying), intermediate (20.6–40.1 h after egg-laying), and final (40.2–61.6 h) stages of development, and kept at a temperature of 28 °C ± 1 °C until collection for processing.ResultsEggs of Ae. aegypti were whitish at the time of oviposition, and then quickly became black. The egg length was 581.45 ± 39.73 μm and the width was 175.36 ± 11.59. Access to the embryo was difficult due to the egg morphology, point of embryonic development, and difficult permeability of the exochorion (mainly in fixation). Only about 5% of the collected eggs were successfully processed. In the initial stage of embryonic development, characteristics suggestive of intense cellular activity were found. In the intermediate stage, the beginning of the segmentation process was evident. In the final phase, it was possible to differentiate the cephalic region and the thoracic and abdominal segments.ConclusionThe chorion was found to be an important protective barrier and a limiting factor for the evaluation of the embryos and mosquito embryonic cells, indicating that further studies need to be carried out to identify the reason that this occurs.Graphical abstract

Highlights

The diseases for which Aedes aegypti is a vector are worrisome
The mosquito Aedes aegypti is of considerable public health importance worldwide, mainly due to its involvement in the transmission of arboviruses
Zika virus infection was reported for the first time in Brazil in May 2015 [7], and the epidemiological scenario involving the disease is characterized by the simultaneous movement of its etiological agents to various

Summary

Introduction

The diseases for which Aedes aegypti is a vector are worrisome. The high vector competence of this mosquito, as well as its anthropophilia and ability to adapt to the urban environment, allows it to exploit many habitats, making its prevention an arduous task. Factors involved include the pathogenicity of the infectious agents and the high competence of its main vector (Ae. aegypti), in addition to its anthropophilia and good adaptation to the urban environment, the context of climate change, and the process of accelerated urbanization, substandard housing policies, and urban infrastructure. These aspects can promote a favorable ambiance to the mosquito life cycle [9, 10] and act as obstacles to prevention measures and effective control with available resources [7, 11]

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