FIELD TESTING SYNTHETIC PREDATOR ODORS FOR ROOF RATS (RATTUS-RATTUS) IN HAWAIIAN MACADAMIA NUT ORCHARDS

Field trials were conducted to determine whether the synthetic predato r odors 3,3-dimethyl-1,2-dithiolane (DMDIT) and (E,Z)-2,4,5-trimethyl- Delta(3)-thiazoline (TMT) were effective at eliciting a behavioral res ponse in wild roof rats (Rattus rattus). The study site was a Hawaiian macadamia nut (Macadamia integrifolia) orchard with a recent history of roof rat feeding damage. The synthetic predator odors were encapsul ated in urethane devices secured to tree branches. Mark-recapture data from:ive-trapping of rats and radio telemetry location data were used to assess behavioral responses of rats to the predator odors. Mark-re capture data indicated that DMDIT and TMT had no effect on capture num bers, reproduction, or body weight of rats. There was some indication that distribution of captures and number of locations relative to trea ted trees in TMT areas were less than in controls, but this pattern wa s not significant. The predator odors had no effect on home range or m edian distance from center of activity (MDIS) of rats as measured by t elemetry. There was a trend of increasing values of MDIS on TMT areas in session 1 but not session 2. Overall we could not detect significan t differences or consistent trends in responses of rats to DMDIT or TM T in these field trials.