LIQUID BAITS FOR RODENT CONTROL - A COMPARISON OF WILD NORWAY VERSUS WILD RICEFIELD RAT RESPONSE TO GLUCOSE PLUS SACCHARIN SOLUTIONS

A series of two-bottle tests were conducted with wild Norway (Rattus n orvegicus) and wild ricefield (Rattus rattus mindanensis) rats to asse ss liquid bait consumption levels. Glucose, a natural sugar, and sacch arin, an artificial sweetening agent, were tested against a combinatio n of the sweeteners in water solution with each rat species. Water bas eline data indicated that ricefield rats drank relatively more water p er day. No species differences, however, were found for consumption le vels of 3.0% glucose or for 0.125% saccharin when fluid intake levels were adjusted for mean body weight differences between species using m etabolic size data transformations to yield relative consumption level s. A species difference was shown for relative consumption of the mixt ure of 3.0% glucose plus 0.125% saccharin in water solution with eithe r sweetener as the alternate choice. Ricefield rats showed a two-fold increase in relative consumption of the mixture compared with solution s of either sweetener alone. Norway rats, in contrast, showed a synerg istic six-fold increase in relative consumption of the mixture compare d with solutions of either component alone. A second series of two-bot tle choice tests with new groups of rats showed that both saccharin an d glucose solution consumption levels were similar in the two species. The lack of glucose plus saccharin synergism in the ricefield rat res ponse was found to be related to less preference by ricefield rats for glucose when paired with saccharin solution compared to the Norway ra t preference pattern. Implications on the potential application of the se results to the control of the two species using liquid bait station s are discussed and summarized. Published by Elsevier Science Ltd.