Diversity of midgut bacteria in larvae and females of Aedes aegypti and Aedes albopictus from Gampaha District, Sri Lanka

Koshila Ranasinghe,Wasana Rodrigo,Deepika Amarasinghe,Lahiru Udayanga,Nayana Gunathilaka

doi:10.1186/s13071-021-04900-5

Koshila Ranasinghe, Wasana Rodrigo + Show 3 more

Open Access

https://doi.org/10.1186/s13071-021-04900-5

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Abstract

BackgroundThe midgut microbiota of mosquitoes maintain basal immune activity and immune priming. In recent years, scientists have focused on the use of microbial communities for vector control interventions. In the present study, the midgut bacteria of larvae and adults of Aedes aegypti and Ae. albopictus were assessed using both field-collected and laboratory-reared mosquitoes from Sri Lanka.MethodsAdults and larvae of Ae. aegypti and Ae. albopictus were collected from three selected areas in Gampaha Medical Officer of Health area, Gampaha District, Western Province, Sri Lanka. Bacterial colonies isolated from mosquito midgut dissections were identified by PCR amplification and sequencing of partial 16S rRNA gene fragments.ResultsAdults and larvae of Ae. aegypti and Ae. albopictus harbored 25 bacterial species. Bacillus endophyticus and Pantoea dispersa were found more frequently in field-collected Ae. aegypti and Ae. albopictus adults, respectively. The midgut bacteria of Ae. aegypti and Ae. albopictus adults (X2 = 556.167, df = 72, P < 0.001) and larvae (X2 = 633.11, df = 66, P < 0.001) were significantly different. There was a significant difference among the bacterial communities between field-collected adults (X2 = 48.974, df = 10, P < 0.001) and larvae (X2 = 84.981, df = 10, P < 0.001). Lysinibacillus sphaericus was a common species in adults and larvae of laboratory-reared Ae. aegypti. Only P. dispersa occurred in the field-collected adults of Ae. aegypti and Ae. albopictus. Species belonging to genera Terribacillus, Lysinibacillus, Agromyces and Kocuria were recorded from Aedes mosquitoes, in accordance with previously reported results.ConclusionsThis study generated a comprehensive database on the culturable bacterial community found in the midgut of field-collected (Ae. aegypti and Ae. albopictus) and laboratory-reared (Ae. aegypti) mosquito larvae and adults from Sri Lanka. Data confirm that the midgut bacterial diversity in the studied mosquitoes varies according to species, developmental stage and strain (field vs laboratory).Graphical abstract

Highlights

The midgut microbiota of mosquitoes maintain basal immune activity and immune priming
Bacterial diversity in field‐collected adult mosquitoes In terms of the number of bacterial colonies growing in the plate count agar (PCA) culture medium, we observed a decreasing trend with increasing dilution of the culture medium in both adults and larvae of each mosquito species (Additional file 1: Figure S1)
The midgut bacteria identified in the field-collected Ae. albopictus adults belonged to six families (Staphylococcaceae, Erwiniaceae, Flavobacteriaceae, Neisseriaceae, Micrococcaceae and Microbacteriaceae)

Summary

Introduction

The midgut microbiota of mosquitoes maintain basal immune activity and immune priming. Conventional mosquito control measures have many downsides, such as the development of insecticide resistance, which have led to efforts to develop novel strategies needed for an integrated vector management (IVM) approach [4]. These efforts have resulted in the Ranasinghe et al Parasites Vectors (2021) 14:433 development of the sterile insect technique (SIT) [5] and incompatible insect technique (IIT) [5, 6] as novel strategies. Scientists have investigated the potential use of microbial communities for vector control interventions. The procedure is referred to as paratransgenesis and has proven to be a highly valuable tool for mosquito control [11]

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