Date of Award


Degree Type


Degree Name

Departmental Honors




Honey bees play an important role in agriculture and the decline of honey bee populations worldwide has generated concern. While the application of pesticides in agricultural settings is often implicated in the deterioration of honey bee population health, pesticide applications contain more than just pesticides; they also contain adjuvants that may have detrimental effects to bee health. One known effect of one type of adjuvant is the suppression of immunity-related genes and consequent increase of viral load in larvae. We investigate the effects of one class of adjuvant, organosilicone surfactants (OSS), on adult honey bee health. In a laboratory based bioassay, adult honey bees were fed various concentrations of an OSS (Xiameter® OFX-0309), alone and with a pesticide (Alticor®) and a fungicide (Tilt®). While survival of the bees was not affected by feeding regimes, bees ate significantly less diet on average if they were fed OSS at certain concentrations-indicating that bees that are exposed to these chemicals may suffer due to low food consumption. We then extracted and sequenced RNA from the bioassay bees to determine transcriptome profiles in bees from each feeding treatment. We found significant downregulation of some genes involved in metabolism in response to the pesticides and upregulation of a cytochrome P450 in response to the pesticides and OSS. In response to adjuvant exposure, serine protease snake was upregulated-a protein involved in innate immunity via activation of the Toll receptor and Rel pathway. OSS appears to interact synergistically with pesticides to exacerbate deleterious changes in gene expression.

Included in

Biology Commons



Faculty Mentor

Karen Kapheim

Departmental Honors Advisor

Kimberly Sullivan