Chemically disrupted ant pheromone trails

Can ants overcome a DEET blockade of a pheromone trail to reach a reward?

Study by Logan Goettl, Mackenzie Korbel, and Leo Lerner.

Chemicals in the environment are a concern that has been present for years. Many chemicals are being introduced into the environment for anthropogenic purposes, interfering with the chemical communication insects use. All species of ants use pheromone chemical trails for various purposes, such as signaling for food or warning of predators. These pheromone trails are essential for ant communication and the overall success of the colony. Cardiocondyla, a genus of ant under the Myrmicinae subfamily, is abundant around the globe but is relatively understudied. This study investigated how chemicals, particularly DEET, impact ant pheromone trails for food among different locations. We baited ants with 1.0g of damp sugar and after a pheromone trail was established, treatments of 2:1, 1:5, and 1:10 concentrations of OFF Deep Woods 25% DEET to isopropyl alcohol were applied, surrounding the food. Ant travel rate was used as a metric for the impact of DEET. We predicted that higher concentrations of DEET would greater reduce the rate of ant entry and for a longer duration. Our results revealed a significant difference in recovery times between highest concentration and lowest concentration, with the higher concentration having a longer recovery time to full trail. Additionally, our results suggested a significant difference in change in average rate among treatments, with highest concentration having the highest change in average rate of entry to sugare. Finally, the patterns of rate of movement were as expected, with decreases in rate shortly after treatment application in all except the control. Since so little is understood about the impact of DEET, these results may be used for greater understanding the physiological effects DEET has on various insects and how pheromone utilizing insects interact with foreign chemicals. Further research studying other species, other insects, or other chemical disruptors may be useful and could greater expand the understanding of human impacts on the environment.

Leo Lerner observes two treatments during an experiment.