Grad Students Receive High Awards for Presentations at National Meeting

Carl Hjelmen speaking

Ph.D. student Carl Hjelmen speaking to an audience at the Graduate Student Forum

MINNEAPOLIS– Congratulations to Ph.D. students Carl Hjelmen and Liz Walsh as they were given awards for the Graduate Ten Minute Paper Presentation Competition at the Entomological Society of America’s annual meeting on Monday, November 16.

Hjelmen’s paper received first place in the SysEB – Citizen Science, New Methods, and Physiology section and was titled “Phylogenetic basis for understanding genome size evolution in Drosophila.”

In his paper, he is looking at the evolution of the genome size in the Drosophila species of flies. In his research, he is utilizing phylogenetic comparative methods to uncover the best fitting hypothesis for genome size changes in the species, given the wealth of sequence data and ease of size estimation for the group.

Hjelmen then compared the quantitative DNA differences consequent to the formation of heteromorphic sex chromosomes to understand how sex influences genome size evolution, specifically through a process called chromosomal degradation.

The comparative methods, he said, would provide a novel and useful way to understanding the genome change between species. Also, he said that the development of the methods would allow the researchers to apply the technique to a variety of other organisms.

Liz presenting

Liz Walsh speaking about her research at a recent meeting. Photo by Rob Williams

Walsh received second place in the 10-minute paper competition in the PBT (Physiology, Biochemisty, and Toxicology) section for her paper titled “The effects of in-hive miticides on honey bee, Apis mellifera, queen retinue response and mandibular pheromones.”

Her research examines some of the sub-lethal effects of the presence of the miticides that are currently being used to treat hives, especially the effects miticides have on the queens when pesticides are already present in the wax in the area where the queens mature.

Walsh explored whether the presence of the chemicals coumaphos and fluvalinate in the queen-rearing beeswax environment had an effect on queen attractiveness to workers by raising queens in miticide-free beeswax or beeswax with miticide.

Walsh said she measured each queen’s retinue and conducted cage experiments whereby five-day-old workers were exposed to mandibular gland extracts of two queen types. She said that the comparisons of both the average worker retinue size per queen type and the number of workers attracted to the gland extracts showed that the queens reared in miticide-free beeswax attacted a significantly larger retinue than the queens reared in the miticide-laden beeswax.

Walsh found that the exposure to miticides during queen development did severely alter the retinue behavior by impacting the queen’s pheromones. The pheromones, she said, are what the queens use to attract her retinue. The results have a very important implication in how in-hive miticides could affect the overall colony health.

Hjelmen is advised by Dr. Spencer Johnston and participated in the Research Experience for Undergraduates (REU) program previously hosted by the department in 2012. Walsh is advised by Dr. Juliana Rangel and participated in the REU program in 2013.

“I am incredibly proud of Liz’s accomplishment as she received second place for the 10 minute oral presentations in her section,”  Rangel said. “This award also helps bring out the research that’s being done at Texas A&M University regarding honey bee biology.”



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