Density and colonization dynamics of gut bacteria essential for development of the African malaria mosquito Anopheles gambiae

Jacob Gafranek, a student at Xavier University, worked with Dr. Michael Strand and graduate student mentor Kerri Coon in the UGA Entomology Department, to look at the gut microbiota of a mosquito disease vector.

Jacob T. Gafranek1, Kerri L. Coon2, Michael R. Strand2

1 Xavier University
2 University of Georgia

Gut bacteria are ubiquitous among animals and are known to play important roles in the immunity, nutrition, and overall health of their hosts. The gut bacterial community of mosquitoes has received attention due to results showing that some bacterial community members in the mosquito midgut can alter competency of the mosquito to transmit a number of important infectious pathogens. More recently, we showed that axenic (i.e. bacteria-free) mosquito larvae do not molt past the first instar. However, axenic larvae colonized by a single bacterial species such as Escherichia coli develop normally. Subsequent work using Aedes aegypti mosquitoes indicates that a particular density of bacteria must be reached in the larval gut to initiate molting. Here, we extend these studies to the African malaria mosquito Anopheles gambiae. We report a robust protocol for colonizing axenic An. gambiae larvae and the number of bacteria required for normal development. We also show that colonization of the larval gut occurs within 8 hours after hatching. These results further demonstrate a fundamental dependence by mosquitoes on their gut bacteria for development. Furthermore, the reported protocol has important implications for future studies characterizing the mechanism by which gut community members modulate mosquito development.

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