Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 25, 2009
Publication Date: June 1, 2009
Citation: Chen, J. 2009. An Automatic System for Continuously Monitoring Digging Volume of Red Imported Fire Ants (Hymenoptera: Formicidae) in the Laboratory. Journal of Economic Entomology. 102:1393-1395. Interpretive Summary: Fire ants build their nest by digging into the soil. This digging behavior can be exploited in fire ant management and can be used to develop sensitive assays for screening fire ant repellants and attractants. A simple, automatic system to study digging dynamics without disturbing ants was developed. The use of this system should benefit scientists studying the digging dynamics by reducing the labor and increasing the data accuracy.
Technical Abstract: In studying the dynamics of ant nest excavation, the nest volume has to be continuously monitored. One common method to estimate nest volume is to weigh the substrate excavated by the ants and then convert the weight into volume. In many laboratory studies, sand has been used as a digging substrate. The excavated sand can be manually collected and weighed; however, manual collection is tedious, particularly when frequent collections have to be performed for a period of several days. Manual collection may also introduce disturbance to the ants. The excavated volume can also be monitored using a video system, which requires sophisticated equipment and software customization, because images have to be transferred into volume data. Few laboratories have such expertise. A simple automatic system for continuously collecting and weighing the excavated sand is described. The system consists of three components: digging arena, sand collecting system and data recording system. A sieve with adequate aperture size is used to separate ants and excavated sand. The sand is automatically collected in a container on the top of a balance. A computer is connected to the balance, which continuously records the weight of the excavated sand. This system does not disturb the ants while collecting data and requires no software customization. It can display the digging curves while it is still collecting data. One concern with this system is the time delay of the weight data. Solutions to reduce and even eliminate such time delay are presented.