Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2005
Publication Date: 1/10/2006
Citation: Mankin, R.W., Benshemesh, J. Geophone detection of subterranean termite and ant activity. Journal of Economic Entomology. 2006. 99(1):244-250. Interpretive Summary: Control of insect pests that are hidden from view presents special problems. Scientists at the Center for Medical, Agricultural, and Veterinary Entomology, Gainesville, FL and Monash University, Australia have tested a geophone system for its capability to detect hidden infestations of insects in soil. The system worked well in detection of weak sounds made by ants, termites, and other small insects in a relatively quiet environment. However, the geophone is most sensitive at low frequencies where background noise typically would overwhelm the insect signal in agricultural and urban environments. Devices similar to this have considerable future potential as tools for detection of weak insect sounds in isolated environments, but limited potential in agricultural areas where wind or vehicle noise are common.
Technical Abstract: A geophone system was used to monitor activity of subterranean termites and ants in a desert environment with low vibration noise. Signals were analyzed from a colony of Rhytidoponera taurus (Forel), a colony of Camponotus denticulatus Kirby, and a termite colony (undetermined Drepanotermes sp.) under attack by ants from a nearby C. denticulatus colony. The geophone recordings were compared with signals recorded from accelerometers in a citrus grove containing Solenopsis invicta Buren workers. Because of their small size, all of these insects produce relatively weak sounds. Several different types of insect-generated sounds were identified in the geophone recordings, including high-frequency ticks produced by R. taurus and C. denticulatus, and bursts of head bangs produced by Drepanotermes. The accelerometer recordings contained ticks by S. invicta that were similar to those produced by C. denticulatus. The S. invicta also produced bursts of ticks with three different stridulation frequencies. The different frequencies may have been produced by different-sized workers. Overall, both systems performed well in enabling identification of high-frequency or patterned pulses. The geophone was more sensitive than the accelerometer to low-frequency signals, but low-frequency insect sound pulses are more difficult to distinguish from background noises than high-frequency pulses. The low cost of multiple-geophone systems may facilitate development of future applications for wide-area subterranean insect monitoring in quiet environments.