Termite soldier head-banging behavior was induced by insertion of a waveguide at depths of 20-30 cm into the soil at basal tree crotches. Acoustic vibrations were measured using a 1 V/g accelerometer coupled to a waveguide with appropriate gain and filtering. Head-banging is a definitive diagnostic signal that is much louder than other termite acoustic emissions, such as chewing, and is easily distinguished from ambient sounds in noisy urban environments. New investigators can become proficient in auditory detection of termites in less than one day and sound detection software is unnecessary. In 2003, 608 trees in City Park, New Orleans were examined in the summer and fall and 42% were infested. Acoustics was necessary to determine infestation in 79% of these infested trees. In 2004 we are examining over 2500 trees in City Park.
Head-banging declines exponentially, ceasing in about 45 minutes in most trees. In highly infested trees head banging may proceed for several hours. Thus permanent bolt or nail waveguides are not usually desirable except in some very highly infested trees where chewing like sounds can be monitored.
Formosan termites can easily be distinguished in the field from Reticulitermes sp. by the temporal pattern of head banging pulses. Distinguishing termites by analyzing frequency is problematic due to different modal frequencies of the waveguides used and different soil coupling conditions.
See more of Ten-Minute Papers, Section Fb. Urban Entomology
See more of Ten-Minute Papers, Section F. Crop Protection Entomology, Subsections Fa and Fb
See more of The 2004 ESA Annual Meeting and Exhibition