Effect of inbreeding on microbiota-mediated host traits in Drosophila melanogaster

Abstract

Microbiota play an important role in regulating host development, physiology and behavior. The hologenome theory suggests that the host and microbiota form the holobiont upon which selection acts. Variation in the host or host-associated microbiota affects the holobiont, and the host traits. Inbreeding reduces the genetic diversity of the host and affects host physiology. Therefore, we propose the hypothesis that removing microbiota in inbred flies will affect host traits more compared to outbred flies. The diet of organisms affects their metabolism and microbiota composition. To understand the effect of diet, we reared flies on two different diets to understand how inbreeding affects microbiota modulated traits in these diets. We observe that inbreeding negatively affects various host physiological processes like survivorship, development, and fecundity. We see that microbiota does not have an effect on life history and behavioral traits. We notice that the effect of microbiota on host traits does not differ between inbred and outbred populations. A novel observation in our study was the increase in the bacterial load in inbred flies compared to outbred flies. Rearing flies on a malnourished diet did not affect how microbiota modulated various host traits in inbred and outbred populations. We observe a reduction in bacterial load in flies reared on malnourished food. Our study shows that inbreeding has an effect on the bacterial load in flies. However, further investigation is needed to understand how this translates to the host traits not being affected by microbiota in inbred and outbred populations.