Study On The Foraging Behavior And Baiting System Of Toxic Bait For Solenopsis Invcita Buren (Hymenoptera: Formicidae)

The red imported fire ant Solenopsis invicta Buren is Hymenoptera, Formicidae, Myrmicinae, Solenopsis.It originates in the Parana River of South America and discoveries at the coast of mainland of China in 2004. Since S. invicta introduced into China, the experts adopted a fire, digging nests, mechanical destruction, nest fumigation, nest boiling water treatment, nest perfusing pesticides, bait method and other urgent control methods. But the treated areas of S. invicta had not been effectively controlled, on the contrary accelerated the ants spread. This study focused on the ants characteristics of behavior, selected the effective attractant and insecticidal components, the comparison between the bait made by outselves and the baits currently on the market sold, study on the best conditions for running the bait, and in the field tested the control effect of the bait and made the bait safety assessment on the ecological environment. The main results of this study were as follows.1.Study on the intrusion behavior of S. invictaThere were scopes among S. invicta nests, and they would struggle when other individuals occupied the scopes. The general trend of struggle were those:big workers would tend to initiate active attack, and the workers number of fight each other was almost equal.But after fight the number of dead small workers was more than the number of big dead workers. But the outcome of struggle was not completely replaced by the other party, and was possibly compatible.In the laboratory, the results of oviposition behavior of virgin females showed that there were two spawning peaks respectively at the 10th and 14th after leaving the mother nest. There were no significant differences about fecundity on the condition of having or no light, larva and virgin females, contrary to the workers.In the laborary, the results of struggle behavior between the S. invicta and Monomorium minimum (Buckley) showed that they would struggle each other when S. invicta encountered with M.minimum, and the fighting capability of S. invicta workers were stronger than that the M. mininum workers. The small workers of S. invicta were more than the medium and large workers to launch active attacks. In the field, the results showed that S. invcita and M. minimum could live together in the same territory. The competition between S. invcita and the native ants was mainly though looting food. S.invicta workers found food though the foraging road of native ants, waited for the partner, reached the food quickly and drove the native ants away, and released pheromone, finally occupied completely.In the field, the results showed that the methods could not effectively control the S. invcita populations such as excavating the mounds, pouring water and pouring pesticides. On the contrary they accelerated the spread of S. invcita.2.The development of poison bait for S. invictaWe found the components of maize flour+20% M+30% N+15% sugar and maize flour+20% M+30% N+10% salad oil had obvious magnetic by screening few attractant.The toxicity results showed that Fenoxycarb and Fipronil had not obvious toxic effect for small and big workers of S. invcta in all observation times.Imidacloprid after 3 days had a rapid toxic effect for S. invcita workers. The toxic effect of A and Y pesticides on the S. invcita big and small workers were increased as the observation time and had significant increase after 6 days, and the effect on big workers was less than that on the small workers.In the 5 Y+A mixture ratio, the CTC for big and small workers after 1d, 3d,6d,9d were significantly greater than 100, showed a significant synergies, and the toxic effect for big and small workers strengthened as the observation time. The transporting capacity and the number of attraction between the baits of 400μg/g,200μg/g, 100μg/g,50μg/g and the control respectively had not significant differences.The results of the test on transfer of Y+A poison baits showed that the dead small workers of been fed 400 ug/g and 200 ug/g Y+A poison baits had significant differences than the control bait after 3 days, and the dead big workers of been fed 400 ug/g and 200ug/g Y+A poison baits had significant differences than the control bait after 6 days. Moreover, the increased workers of been fed toxic bait could not speed up the transmission of Y+A poison bait. 3.The field control effect of Y+A poison baitThe results of the field test on decision of Y+A poison bait dosage showed that the mortality of nests were respectively 65%,79% and 83% for 100,200,400μg/g Y+A poison baits.The results of the comparison on the toxicity of 4 poison baits showed that the poison baitⅠled to the death of a large number of workers and many winged reproductives, and the mortality of nest achieved 47%.The mortality and the mobility of nest for poison baitⅡ(0.015% spinosad) respectively achieved 28% and 8% after 5 weeks. The poison baitⅢled to a little deaths and all nests transported after 1 week. The nest mortality was 86.7% after applying 400μg/g Y+A poison bait.4.The applying technology of attractantThe results of field baiting on the best conditions showed that the appropriate distance of the attractant was from the mound base to 50cm. The appropriate time of applied attractant was the morning and the dew dried. The attractant rickles should be few around the mound and the overall attractant rickles should be relatively plentiful.5.The safety evaluation of Y+A poison baitThe Y+A poison bait was non-toxic for Kunming mice and not greatly effect on the native ants diversity in the field test.