Large-scale bioacoustic monitoring to elucidate the distribution of a non-native katydid

For animals that produce species-specific audible sounds, environmental recordings combined with automated acoustic monitoring software (passive acoustic monitoring, PAM) may be an effective monitoring tool because it allows audio data from many, widely distributed autonomous recording units (ARUs) to be processed in a relatively short period of time. Males of many insect species produce loud, species-specific mating songs, yet acoustic insects have received less attention from PAM relative to vertebrates.

We evaluated the use of PAM to monitor, Roeseliana roeselii (Orthoptera, Tettigoniidae), an acoustic insect that has expanded its range to Alberta, Canada far outside its naturalized North American range. We analyzed environmental recordings from ARUs: 1) at two control sites known to be occupied by R. roeselii, and 2) across Alberta established by the Alberta Biodiversity Monitoring Institute (ABMI) to search for new populations.

PAM successfully detected R. roeselii at the two control sites, but not at any of the 74 ABMI sites that we analyzed. Despite the failure to detect new locations of R. roeselii, our analysis of ABMI environmental recordings detected several other species of acoustic insects, including Orchelimum gladiator, Gryllus sp. and Allonemobius spp.

Our results add to the growing body of work showing the feasibility of using PAM for acoustic insects. We make suggestions for how to maximize the effectiveness of this monitoring tool for the conservation and management of singing insects in North America.