Effect Of Super-Absorbent Polymers On Foraging Behaviors Of Formosan Subterranean Termites(Blattodea:Rhinotermitidae)

Coptotermes formosanus Shiraki(Blattodea: Rhinotermitidae)is one of the most important urban and forestry pests,which causes in great economic losses.Use chemical termiticide has caused serious problems to the environment.Nowadays,baiting is widely applied for termite management because this method is effective and environmental friendly.However,the success of baiting system largely depends on the bait matrix,the design of bait station,as well as the foraging behaviors of termites.Moisture conditions of food and soil are essential for foraging activities of subterranean termites.However,the current bait station usually use dry wood block as the bait matrix,and the attraction of termite bait needs to be improved.Super-absorbent polymer is a water-retaining agent that has been applied to increase moisture of agricultural soils,which may increase the moisture of bait matrixes and soil surrounding baiting containers and therefore attract termites and increase their foraging activities.In the present study,four super-absorbent polymers(i.e.,polyacrylamide/attapulgite composite,sodium polyacrylate-cross-linked,poly(acrylamide-co-acylic acid)potassium salt-cross-linked,potassium polyacrylate-cross-linked)were selected for the following two experiments: under the conditions of dry and wet substrate,aggregation and feeding preferences of C.formosanus were investigated when responding to the super-absorbent polymer was buried within soil(two-choice tests)or filled in the baiting containers(multiple-choice tests).In addition,the effect of polyacrylamide/attapulgite composite on the survivorship,body water percentage and wood consumption of C.formosanus were studied(no-choice tests).The consumption of wood in the two-choice tests showed that termites consumed significantly more wood when super-absorbent polymer was buried within dry soil than the controls(no super-absorbent polymer was provided).However,super-absorbent polymer buried within wet soil did not significantly affect foraging behaviors of termites.In addition,the aggregation percentage results showed that termites significantly tend to choose the treated chambers(30%-water saturated sodium polyacrylate-cross-linked was buried)under dry-substrate conditions,but there is no significant difference in the results of the remaining 3 types of super-absorbent polymer.Multiple-choice tests showed no aggregation or feeding preference of termites in the baiting containers filled with super-absorbent polymer compared with the soil filled or unfilled ones,whenever the substrate was dry or wet.In addition,the no-choice tests of two kinds of experiments with polyacrylamide/attapulgite composite showed that the presence of polyacrylamide/attapulgite composite(buried within soil or filled in baiting containers)significantly increased wood consumption and body water percentage of termites as well as wood moisture under dry-substrate conditions.In summary,our studies suggest that burying super-absorbent polymer within dry soil may enhance foraging activities of termites,especially under drought conditions.However,filling the bait stations with super-absorbent polymer may not effectively attract termites.