Bacterial communities in carnivorous pitcher plants colonize and persist in inquiline mosquitoes

Abstract

AbstractBackgroundThe leaves of carnivorous pitcher plants harbor diverse communities of inquiline species, including bacteria and larvae of the pitcher plant mosquito (Wyeomyia smithii), which aid the plant by processing captured prey. Despite the growing appreciation for this microecosystem as a tractable model in which to study food web dynamics and the moniker ofW. smithiias a ‘keystone predator’, very little is known about microbiota acquisition and assembly inW. smithiimosquitoes or the impacts ofW. smithii-microbiota interactions on mosquito and/or plant fitness.ResultsIn this study, we used high throughput sequencing of bacterial 16S rRNA gene amplicons to characterize and compare microbiota diversity in field- and laboratory-derivedW. smithiilarvae. We then conducted controlled experiments in the laboratory to better understand the factors shaping microbiota acquisition and persistence across theW. smithiilife cycle. Methods were also developed to produce axenic (microbiota-free)W. smithiilarvae that can be selectively recolonized with one or more known bacterial species in order to study microbiota function. Our results support a dominant role for the pitcher environment in shaping microbiota diversity inW. smithiilarvae, while also indicating that pitcher-associated microbiota can persist in and be dispersed by adultW. smithiimosquitoes. We also demonstrate the successful generation of axenicW. smithiilarvae and report variable fitness outcomes in gnotobiotic larvae monocolonized by individual bacterial isolates derived from naturally occurring pitchers in the field.ConclusionsThis study provides the first information on microbiota acquisition and assembly inW. smithiimosquitoes. This study also provides the first evidence for successful microbiota manipulation in this species. Altogether, our results highlight the value of such methods for studying host-microbiota interactions and lay the foundation for future studies to understand howW. smithii-microbiota interactions shape the structure and stability of this important model ecosystem.