Efficacy evaluation of a thiazoline compound as a new deer-proof repellent

Abstract

We carried out a feasibility test using odor of a thiazoline compound that induces the innate fear reaction of mice, aiming to develop a new sika deer repellent in young conifer plantations. It has revealed that predator-originated thiazoline compounds invoke a fear reaction in mice in a laboratory and the reaction is determined genetically. We examined whether 2-(Methylthio)-2-thiazoline (C ₄ H ₇ NS ₂ , hereafter 2MT2T) would inhibit the foraging behavior of captive sika deer (Cervus nippon). At first, we confirmed that a self-build volatilizer showed a volatilization rate of approximately 100 mg/h, and we monitored the odor-spreading process with an odor meter. Secondarily, automatic video cameras recorded the foraging behavior of captive sika deer to Japanese knotweed (Fallopia japonica var. japonica) fresh leaves beside the two volatilizers with 2-ml 2MT2T. We recognized only four times of avoidance behavior amid 1,590 times of foraging behavior, and the sika deer ate up knotweed leaves within 15 h after the beginning of the trials. It can be hard to expect the repellent effect of 2MT2T against sika deer in an open field to invoke avoidance behavior or to control foraging behavior.