Fitness of gnotobiotic Rhodnius prolixus nymphs

Kissing bugs (Hempitera: Reduviidae) are obligately and exclusively blood feeding insects. Vertebrate blood is thought to provide insufficient B vitamins to insects, which rely on obligate symbiotic relationships with bacteria that provision these nutrients. Kissing bugs harbor environmentally acquired bacteria in their gut lumen, without which they are unable to develop to adulthood. Early experiments identified a single bacterial species, Rhodococcus rhodnii, as a symbiont of Rhodnius prolixus, but modern studies of the kissing bug microbiome suggest that R. rhodnii is not always present or abundant in wild-caught individuals. We asked whether R. rhodnii or other bacteria alone could function as symbionts of R. prolixus. Bacteria-free (axenic) insects were produced whose microbiome could be experimentally manipulated to produce insects with known microbiomes (gnotobiotic). We found that gnotobiotic insects harboring R. rhodnii alone developed faster, had higher survival, and laid more...