Parasitic Horn Fly Serious Threat to Milk Production

Kande Jones, a Molecular Biology major at Abilene Christian University in Abilene, TX, is using genetic techniques to improve control of the horn fly population. Whether interested in agriculture, entomology, microbiology, genetics, environmental conservation or education, this project extends into multiple fields.

Horn flies are a significant parasite throughout the South Central US and South America. They lay their eggs in cow manure and live off the blood of the cow as adults. As few as 30 flies can provide enough stress on the cow to affect milk production and calf weight gain. However, if pesticidal ear tags are used for insect control, it is recommended that you wait until at least 100 flies infect the animal before use, because the flies quickly develop resistance to the chemicals.

Wolbachia is a bacterium that naturally lives within many insects, including the horn flies, and affects reproductive success. There are multiple strains of Wolbachia and only adult flies that are infected by the same strain are able to produce viable offspring. If the adults are infected by different strains, or one is uninfected, they will only produce unfertilized eggs.

Under the direction of Dr. Xu, her molecular genetics and entomology professor, Kande is working with fellow students as part of the Horn Fly Research Project. The team hopes to develop a new strain of Wolbachia in the lab and introduce the new strain into a horn fly colony. This introduction of a new strain of bacteria will significantly increase the likelihood of unmatched adults producing nonviable eggs, greatly affecting population numbers.

This research is in conjunction with a USDA-funded project to determine the genetic basis for insecticide resistance in horn flies. To begin this new project, they need horn fly cell-lines in which to grow the Wolbachia strains. These cell-lines cost several thousand dollars and they need $1000 to get started.