This dissertation is accessible only to the Illinois State University community.

  • Off-Campus ISU Users: To download this item, click the "Off-Campus Download" button below. You will be prompted to log in with your ISU ULID and password.
  • Non-ISU Users: Contact your library to request this item through interlibrary loan.

Date of Award


Document Type

Thesis-ISU Access Only

Degree Name

Master of Science (MS)


School of Biological Sciences

First Advisor

Ben Sadd


The microbial world captivates the minds of health professionals, scientific investigators, and the general public. Often the fascination with these microscopic organisms results from the dire illnesses they can cause. Recent studies are rewriting the narrative around these microbes, highlighting the important roles they play in maintaining the health and development of many host organisms. One such bacteria, Snodgrassella alvi, resides in the gut of many Apid bee species. Responsible for host defense, immunological development, and nutritional gain, studies of S. alvi are critical for our understanding of bumble bee health. Despite considerable research surrounding this beneficial gut colonizer, the mechanisms and factors driving S. alvi colonization in bumble bees remain poorly understood. I demonstrate the importance of host and bacterial strain genotype in successful S. alvi colonization within the hind gut of the common eastern bumble bee, Bombus impatiens. Previous work supported the idea of specificity in colonization success of S. alvi strains isolated from the Bombus and Apis genera, with strains better colonizing their native host genus. The results of my work show differential colonization of several S. alvi strains, isolated from multiple colonies of a single host species, B. impatiens, following experimental inoculation into hosts from distinct genotypic units based on their colonies of origin. Further, during the establishment of a S. alvi strain bank needed to carry out the above experiment I have characterized strain phenotypes and diversity between strains isolated from A. mellifera and different bumble bee species. This analysis hints at a greater degree of sharing of S. alvi strains across bumble bee and honey bee hosts than has previously been reported. The host-genotype by microbe-genotype interaction discovered in this work advances our understanding of factors influencing successful microbiota colonization of an important pollinator host.


Imported from ProQuest Sauers_ilstu_0092N_11334.pdf


Page Count


Off-Campus Download