Assessing Factors Associated With Detection Probability of the Japanese Burrowing Cricket (Velarifictorus micado) on Point Count Surveys

Abstract

Conservationists are tasked with developing effective monitoring regimes for wildlife species of interest. Effective monitoring is especially important for invasive species to map their spread and develop management strategies. One invasive species, the Japanese burrowing cricket (Velarifictorus micado), is steadily spreading across the eastern United States, however, aural monitoring protocols have never been developed. To inform potential monitoring efforts for this invasive insect, we conducted aural point count surveys for V. micado across the Inner Bluegrass Region of central Kentucky, United States, at all hours of the day from 19 September to 5 November 2024. We generated single-season occupancy models which allowed us to assess which variables (windspeed, barometric pressure, temperature, time of day, and ordinal date) that best predicted variation in detection probability. We detected V. micado at 16 of 49 sites (naive occupancy = 0.33). Detection probability (p̂) was generally low (p̂ = 0.30 (95% CI: 0.15–0.51)), and our top model indicated that time of day and ordinal date were the strongest predictors of detection probability. Specifically, detection probability was maximised at sunset (p̂ = 0.93) and declined linearly to sunrise (p̂ = 0.24) and approached zero before noon. The effect of ordinal date was less dramatic and included a linear decline from 19 September (p̂ = 0.71) to 5 November (p̂ = 0.10). Our results clearly demonstrate that the optimal conditions for V. micado point count surveys are during the month of September and in the hours immediately preceding sunset. Future work assessing patterns of occupancy probability would be valuable in understanding the ecology of this invasive insect.