Sound of wood-boring larvae and its automated detection

Abstract

Stevens Institute of Technology has been investigating solutions for instrumental detection of invasive species at ports of entry. Stevens has built several acoustic systems for detection of acoustic/ vibrational signals produced by insects. This paper presents acoustic signals recorded in tests conducted in APHIS Otis Lab using tree bolts infested by Asian Longhorn Beetle, ALB and Emerald Ash Borer, EAB larvae. The analysis of the recorded sounds extracted the signal features that allowed larval classification. These features include frequencies of the generated pulses, their durations and frequencies of pulse envelops. These features showed a clear separation of ALB and EAB. For example, the main frequency of the ALB sound was in the range of 3.8–4.8 kHz, while for EAB it was between 1.2 and 1.8 kHz. A preliminary algorithm for automated insect signal detection was developed. The algorithm automatically detects pulses with parameters typical for the larva-induced sounds and rejects non-insect sound pulses. Detection is announced when the number of detected pulses for some time (5 min) exceeds the definite threshold. In the conducted test, this algorithm provided detection of a larva in all tested samples without false alarms. [This project was funded under contract with the U.S Department of Homeland Security (DHS) Science and Technology Directorate (S&T), contract HSHQDC-10-A-BOA35.]