Research Topics
A recent video made by the Boise State media team about our research into the Big Sagebrush leaf microbiome.
Pitcher Microcosm communities
The aquatic pools in pitchers are ideal model systems for community ecology because the contained communities of arthropods and microbes are clearly defined and can be replicated across many pitchers. The Bittleston Lab uses pitcher bacterial communities to study the patterns and processes of community assembly, and also to understand how community composition is tied to ecosystem function (for example, figuring out which bacteria and which interactions among species regulate key enzymatic activity). Our lab studies these communities both in the field and in the lab, and thus can choose to work at a level that is more realistic or a level where more factors can be controlled, to focus on specific processes. This research topic covers community ecology, host-microbiome dynamics, and how bacterial metabolism drives ecosystem function.
Previous research on pitcher plant microcosm communities has investigated how characteristics of host plants select for particular compositions, and has compared communities and functional roles in independently-evolved pitcher plants (Bittleston et al., 2018 eLife). We have also examined co-occurrence networks and the effects of pitcher acidity on community composition (Bittleston, 2016 book chapter) and tested how metabarcoding captures the eukaryotic component of Southeast Asian pitcher communities (Bittleston et al., 2016 Austral Ecology). Current work in progress quantifies how past events and current environment influence in vitro community assembly of pitcher bacteria (manuscript in preparation), and investigates the outcome of mixing different stabilized communities (“community coalescence”) and of long-term evolution within communities.
sagebrush phyllosphere microbes
Many groups of bacteria and fungi live on and in plant leaves, without causing disease. These phyllosphere communities have to be adapted for their particular niche - often one exposed to lots of light and plant secondary chemicals. Sagebrush, in particular, produces many leaf chemicals that are known to be antimicrobial, including camphor, terpenoids and tannins. A goal of the Bittleston Lab is to characterize which bacteria and fungi colonize sagebrush leaves, and to figure out what they are doing and if they affect the plant or its herbivores. We also aim to examine interactions among phyllosphere bacteria and fungi, to understand how the communities form and what stabilizes them.
Convergent interactions
The concepts of convergent evolution and community convergence highlight how selective pressures can shape unrelated organisms or communities in similar ways. Convergent interactions is a related concept that describes the independent evolution of multispecies interactions with similar physiological or ecological functions. A focus on convergent interactions clarifies how natural selection repeatedly favors particular kinds of associations among species. Characterizing convergent interactions in a comparative context is likely to facilitate prediction of the ecological roles of organisms (including microbes) in multispecies interactions and selective pressures acting in poorly understood or newly discovered multispecies systems. Examples of convergent interactions include: vertebrates and their gut bacteria; ectomycorrhizae; insect–fungal–bacterial interactions; pitcher-plant food webs; and ants and ant–plants.
We compared the microbiomes of convergently evolved, North American and Southeast Asian pitcher plants in-depth in our eLife paper, with two nice articles written about the paper’s findings at UW Madison and in the Harvard Gazette. In addition, there is a beautiful illustrated overview made by Caroline Hu.
