Association between fertilizer-mediated changes in microbial communities and Aedes albopictus growth and survival

Authors: Muturi, Ephantus; Ramirez, Jose; Rooney, Alejandro - Alex; Dunlap, Christopher

Submitted to: ACTA TROPICA
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/21/2016
Publication Date: 8/22/2016
Publication URL: http://handle.nal.usda.gov/10113/5583301
Citation: Muturi, E.J., Ramirez, J.L., Rooney, A.P., Dunlap, C.A. 2016. Association between fertilizer-mediated changes in microbial communities and Aedes albopictus growth and survival. Acta Tropica. 164(2016):54-63.

Interpretive Summary: Mosquitoes develop in a variety of aquatic habitats that are frequently exposed to fertilizers from nearby farmlands. The aim of this study was to examine the individual and combined effects of two synthetic fertilizers (ammonium sulfate and potassium chloride) on mosquito life history traits. We also examined how aquatic bacterial and fungal communities respond to fertilizer exposure and how these responses relate to mosquito survival and development. Ammonium sulfate reduced mosquito survival to adulthood and prolonged their development time but these effects were not observed in potassium chloride or a mixture of the two fertilizers. Fertilizer treatments altered both the microbial diversity and composition but only microbial composition was significantly associated with mosquito survival and development. These findings suggest that anthropogenic nutrients can affect mosquito ecology by disrupting the microbial communities that serve as food for mosquito larvae and advance current knowledge on the potential impact of agricultural practices on mosquito-borne diseases.

Technical Abstract: Contamination of aquatic habitats with anthropogenic nutrients has been associated with an increase in mosquito larval populations but the underlying mechanisms remain poorly understood. We examined the individual and combined effects of two synthetic fertilizers (ammonium sulfate and potassium chloride) on Aedes albopictus survival, development time, and sex ratio. The bacterial and fungal communities of water samples from different fertilizer treatments were also characterized by MiSeq sequencing of the 16S rRNA gene (bacteria) and internal transcribed spacer 1 (fungi) and their relationship with mosquito survival and development determined. Mosquitoes from ammonium sulfate treatment had significantly lower survival and longer development times compared to those from control, potassium chloride or a mixture of the two fertilizers. Fertilizer treatment had no significant effects on Ae. Albopictus sex ratio although ammonium sulfate treatment tended to be more biased towards males relative to the other treatments. There were no significant effects of fertilizer treatment on fungal communities. However, potassium chloride treatments had lower bacterial diversity compared to the other treatments and the bacterial community structure of control and potassium chloride treatments differed significantly from that of ammonium sulfate and a mixture of the two fertilizers. Microbial composition but not diversity was significantly associated with mosquito survival and development. These findings suggest that anthropogenic nutrients can affect mosquito growth and development by disrupting the microbial communities that serve as food for mosquito larvae.