RESUMO
Symbiotic bacteria have a significant impact on the formation of defensive mechanisms against fungal pathogens and insecticides. The microbiome of the mosquito Aedes aegypti has been well studied; however, there are no data on the influence of insecticides and pathogenic fungi on its structure. The fungus Metarhizium robertsii and a neurotoxic insecticide (avermectin complex) interact synergistically, and the colonization of larvae with hyphal bodies is observed after fungal and combined (conidia + avermectins) treatments. The changes in the bacterial communities (16S rRNA) of Ae. aegypti larvae under the influence of fungal infection, avermectin toxicosis, and their combination were studied. In addition, we studied the interactions between the fungus and the predominant cultivable bacteria in vitro and in vivo after the coinfection of the larvae. Avermectins increased the total bacterial load and diversity. The fungus decreased the diversity and insignificantly increased the bacterial load. Importantly, avermectins reduced the relative abundance of Microbacterium (Actinobacteria), which exhibited a strong antagonistic effect towards the fungus in in vitro and in vivo assays. The avermectin treatment led to an increased abundance of Chryseobacterium (Flavobacteria), which exerted a neutral effect on mycosis development. In addition, avermectin treatment led to an elevation of some subdominant bacteria (Pseudomonas) that interacted synergistically with the fungus. We suggest that avermectins change the bacterial community to favor the development of fungal infection.
Assuntos
Aedes/microbiologia , Inseticidas/farmacologia , Metarhizium/fisiologia , Microbiota/efeitos dos fármacos , Animais , Antibiose/efeitos dos fármacos , Bactérias/classificação , Bactérias/efeitos dos fármacos , Bactérias/genética , Bactérias/isolamento & purificação , Carga Bacteriana , Ivermectina/análogos & derivados , Ivermectina/farmacologia , Larva/microbiologia , Controle de Mosquitos , Esporos Fúngicos/fisiologiaRESUMO
The population structure of bloodsucking mosquito larvae in temporary and constant water bodies of the northern Kulunda steppe was investigated. The seasonal dynamics of the population density, the number of species in different types of reservoirs, and average density of each species are given. The productivity of water reservoirs in relation to mosquitoes of the family Culicidae is analyzed. The basic factors affecting the distribution of larvae of dominant species between different water bodies were revealed. The degree of correlation between the structure of bloodsucking mosquito larva assemblages and the type of the reservoir was established.
