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Tag: Mark Brown

Predaceous Toxorhynchites mosquitoes require a living gut microbiota to develop

Most species of mosquitoes are detritivores that feed on decaying plant and animal materials in their aquatic environment. Studies of several detritivorous mosquito species indicate that they host relatively low diversity communities of microbes that are acquired from the environment while feeding. Our recent results also indicate that detritivorous species normally require a living gut microbiota to grow beyond the first instar. Less well known is that some mosquitoes, including those belonging to the genus Toxorhynchites, are predators that feed on other species of mosquitoes and nektonic prey. In this study, we asked whether predaceous Toxorhynchites amboinensis larvae still require living microbes in their gut in order to develop. Using the detritivorous mosquito Aedes aegypti as prey, we found that T. amboinensis larvae harbour bacterial communities that are highly similar to that of their prey. Functional assays showed that T. amboinensis first instars provided axenic (i.e. bacteria-free) prey failed to develop, while two bacterial species present in gnotobiotic (i.e. colonized by one or more known bacterial species) prey successfully colonized the T. amboinensis gut and rescued development. Axenic T. amboinensis larvae also displayed defects in growth consistent with previously identified roles for microbe-mediated gut hypoxia in nutrient acquisition and assimilation in A. aegypti. Collectively, these results support a conserved role for gut microbes in regulating the development of mosquitoes with different feeding strategies.

Kerri L. Coon, Luca Valzania, Mark R. Brown and Michael R. Strand. Proc Biol Sci. 2020 Jan 29;287(1919):20192705. doi: 10.1098/rspb.2019.2705

Trainee Spotlight: Ruby Harrison

trainee Ruby Harrison

NIH T32 trainee Ruby Harrison is a co-advised by Drs. Michael Strand and Mark Brown in the UGA Department of Entomology. She received a Bachelor’s of Science in Entomology from the University of Wisconsin-Madison in 2012 and lived in Madison an additional two years working with mosquitoes as a research assistant. Before coming to UGA to begin my doctoral studies, she spent a year in Gabon, Africa, working as a tropical ecology field technician.

Ruby’s research focus

Ruby studies mosquito-microbiome interactions. Currently, she is investigating the influence of the gut microbiome on mosquito reproductive processes. She also plans to begin exploring the role of the mosquito microbiome in deterring pathogen infection in the very near future.

“I chose this research focus because I was inspired by the research of a former graduate student of Dr. Strand’s, Dr. Kerri Coon. Kerri pioneered fascinating work on the influence of the microbiota on development in mosquitoes in the immature (larval) stage,” said Ruby. “I saw an opportunity to extend her work, to observe if the same bacterial signal essential to larval development is recapitulated in any way in the adult stage.”

More broadly, she sees insect-microbe interactions as a promising field which may offer new solutions for mosquito population control and reduction of pathogen transmission.

NIH T32 Fellowship helps trainees achieve their goals

Ultimately, Ruby hopes to build a career as a vector biologist. For the capstone experience provided by the NIH T32 Training Grant, she is interested in returning to francophone West or Central Africa to work with mosquitoes in the field.

“I am truly grateful to receive the T32 pre-doctoral training fellowship, which presents me the opportunity to interact more closely with the CTEGD, opens doors for possible collaboration, and will help me to pursue my research goals,” said Ruby.