Culex quinquefasciatus larvae development arrested when fed on Neochloris aquatica

Abstract

Culex quinquefasciatus is a cosmopolitan species widely distributed in the tropical and subtropical areas of the world. Due to its long history of close association with humans, the transmission of arboviruses and parasites have an important role in veterinary and public health. Adult females feed mainly on birds although they can also feed on humans and other mammals. On the other hand, larvae are able to feed on a great diversity of microorganisms, including microalgae, present in natural or artificial breeding sites with a high organic load. These two particularities, mentioned above, are some of the reasons why this mosquito is so successful in the environment. In this work, we report the identification of a microalga found during field sampling in artificial breeding sites, in a group of discarded tires with accumulated rainwater. Surprisingly, only one of them had a bright green culture without mosquito larvae while the other surrounding tires contained a large number of mosquito larvae. We isolated and identified this microorganism as Neochloris aquatica, and it was evaluated as a potential biological control agent against Cx. quinquefasciatus. The oviposition site preference in the presence of the alga by gravid females, and the effects on larval development were analyzed. Additionally, microalga effect on Cx. quinquefasciatus wild type, naturally infected with the endosymbiotic bacterium Wolbachia (w+) and Wolbachia free (w−) laboratory lines was explored. According to our results, even though it is chosen by gravid females to lay their eggs, the microalga had a negative effect on the development of larvae from both populations. Additionally, when the larvae were fed with a culture of alga supplemented with balanced fish food used as control diet, they were not able to reverse its effect, and were unable to complete development until adulthood. Here, N. aquatica is described as a biological agent, and as a potential source of bioactive compounds for the control of mosquito populations important in veterinary and human health.

Assessment of susceptible Culex quinquefasciatus larvae in Indonesia to different insecticides through metabolic enzymes and the histopathological midgut

“…Additionally, many reports have shown that Cx. quinquefasciatus transmits sylvatic arbovirus from birds, indicating that it may function as an important bridge between sylvatic arbovirus transmission from birds to humans in urban areas ( Lopes et al., 2019 ; Gil et al., 2021 ; Pereira et al., 2020 ).…”

Terrestrial subsidies and light affect an aquatic micro‐ecosystem in unexpected ways

“…We interpret this through a higher supply of nutrients, in particular N and P. However, this statement must be taken with caution as other nutrients were manipulated conjointly with N and P, and colimitation amongst different nutrients is common (Kaspari & Powers, 2016). The lack of difference in survival is more puzzling, especially when considering that C. quinquefasciatus is a generalist species whose larvae fare especially well in water with high organic loads (Gil et al, 2021;Roberts & Kokkinn, 2010;Santana-Martínez et al, 2017), which is the case of mesocosms that received leaf litter and faeces. It is possible that any increase in survival in those mesocosms that received leaf litter and faeces was counterbalanced by the production of noxious metabolites of microorganisms growing on remains of Rubus armeniacus (Rosales: Rosaceae), the food plant of C. morosus, the insects that produced the faeces.…”

“…All larvae were of a similar size, being from the same generation of a laboratory colony, and were randomly seeded within the mesocosms shortly after hatching to the first instar. This mosquito is a generalist species feeding on a broad variety of microorganisms and particulate organic matter through the filtering of water in its mouthparts (Gil et al, 2021;Merritt et al, 1992;Östman et al, 2008). This species can compete with other macroscopic filter-feeders such as cladocerans (Blaustein & Chase, 2007;Duquesne et al, 2011), so we ensured that no such organism was present within the mesocosms.…”

“…This species can compete with other macroscopic filter-feeders such as cladocerans (Blaustein & Chase, 2007;Duquesne et al, 2011), so we ensured that no such organism was present within the mesocosms. The species is able to exploit a wide variety of larval habitats and is the vector of several medically important diseases impacting humans (Gil et al, 2021;Gordillo & Walton, 2010;Ong et al, 2021). Having a treatment where larvae are excluded allows us to fully understand their effects on nutrients and microorganisms.…”

Use of micro and macroalgae extracts for the control of vector mosquitoes

“…Since algae live in mosquito breeding areas, they are consumed as food by mosquitoes. Therefore, female mosquito species, such as Culex quinquefasciatus , choose areas containing microalgae as oviposition substrates ( Gil et al, 2021 ). In addition, algae make important contributions to mosquito control by supporting mosquito predators such as dragonflies and aquatic insects in the habitat they create ( Chaves & Koenraadt, 2010 ).…”