Espinoza, Elida Maria (2017-04). The Role of Quorum Sensing Bacteria Proteus mirabilis on the Behavioral Ecology of the Red Imported Fire Ant, Solenopsis invicta Buren (Hymenoptera: Formicidae). Doctoral Dissertation.
Thesis
Interkingdom interactions describe dynamic and complex relationships between prokaryotes and eukaryotes sharing an environment. In particular, bacteria-animal interactions studies have hypothesized the intrinsic role bacteria have on animal behavior. In this study, foraging rate and nestmate recognition behaviors of the red imported fire ant (RIFA) Solenopsis invicta (Buren) (Hymenoptera: Formicidae) were used to determine whether quorum sensing bacteria Proteus mirabilis played a role in these ant behaviors. First, a regional and colony level bacterial survey of S. invicta was conducted to determine the bacterial communities found on the worker caste, reproductive caste, brood and midden using 16S rRNA gene v4 region amplicon sequencing. The bacterial survey revealed high bacterial diversity in adult castes versus conserved, low bacterial diversity in brood. Ecological regions were important in establishing the available bacterial community. Proteus bacteria was found in all ecoregions and colony member functional categories. Behavioral assays and quantification of bacteria concentrations on ants, established that P. mirabilis played no significant role in nestmate recognition of S. invicta colonies. Foraging responsiveness experiments revealed 10^5 CFU/mL P. mirabilis increased attraction to high carbohydrate honey water baits in different S. invicta colonies. The models and methodologies used in this study can be used to evaluate additional bacteria-ant interactions or develop the mechanisms underlying S. invicta increased attraction to high carbohydrate baits exposed to P. mirabilis.
