Insects are the most abundant and diverse animals on planet Earth and rely on their diverse microbiomes to be so. The insect gut microbiome is vital in the growth and development of many insect species. Trichoplusia ni, the cabbage looper, is a generalist herbivore, but little is known about its microbiome. In this study, a metagenomic analysis of fecal samples was used to determine the effect of diet on the microbiome of T. ni larvae. Larvae were reared on six plant species, the microbiome was sampled from fecal material, and the phyllosphere was sampled from leaves the larvae ate. Bacteria were identified using 16S ribosomal RNA gene sequences, and diversity was quantified. Similar phyla, classes, and families were found in both types of samples, suggesting T. ni larvae primarily obtain their gut microbiome from their diet. However, the gut microbiome of T. ni larvae is not identical to the phyllosphere, particularly in relative abundances, suggesting that other factors in the insect gut environment may further modify the diversity of the microbiome. This study adds to the growing body of evidence about the implications of diet for the insect gut microbiome.


This research was supported by a mini grant from the UNG Center for Undergraduate Research and Creative Activities, and by the Biology Department. Brandon Mangum provided technical assistance. Margaret Smith and Erin Barding provided T. ni larvae from their culture. Davison Sangweme and Alex Lowrey provided feedback on an earlier draft of this manuscript. We thank the Biology 1108K students that participated in rearing and culturing larvae during the Spring 2018 semester.