| Odontotermes formosanus (Shiraki) is an important pest of agronomic crops, plantations and forestry, and badly destroys earthen dikes and dams in China. The foraging behavior of O. formosanus was studied totally in the thesis. Furthermore, the high effective and environmentally friendly baiting system against O. formosanus was constructed and applied. The major results are summarized as following: 1. Study on the tunneling and foraging behavior of O. formosanusIn the laboratory, the differences of tunneling behavior between O. formosanus and Reticulitermes chinensis were studied by the planar sand plate. Furthermore, the effect of sand diameter on the tunneling rate of O. formosanus was also studied. We found that the worker of O. formosanus in the origin quickly started to tunnel in higher speed, and the radiate primary tunnels were constructed around the sand plate. However, the workers of R. chinensis resorted in the origin for a longer time, and the non-radiate primary tunnels were constructed in lower speed in the sand plate. The results showed that the number and width of primary tunnels of O. formosanus was significantly more than that of R. chinensis, but the angle between two primary tunnels, branching number of primary tunnels and intersecting ratio of tunnels were significantly less than those of R. chinensis. In addition, the results showed that the tunneling rate of O. formosanus was affected significantly by sand diameter, and there was choice for sand size during the tunneling behavior in O. formosanus.In the laboratory, the results showed that there was no significant difference for the number of primary tunnels between the two behaviors, but the branching numbers of primary and secondary tunnels of the foraging behavior were significantly less than those of the tunneling behavior. The results of the foraging behavior test showed that the tunnel width about feeding site was significantly bigger than that about origin. In addition, number of primary tunnels across feeding sites was significantly more than that of subaltern tunnels across feeding sites. Furthermore, there were 2 feeding loops around 60 % of feeding sites found by foraging workers.2. Study on phagostimulating pheromone in O. formosanusWe observed that cumulate acini forming labial gland were oblate in the shape, which were joined by acinar ducts. In addition, there was significant difference in the structures of acinar cells of labial gland among workers, soldiers and alates in O. formosanus. The results showed that there was significant phagostimulating effect on workers for distilled water extracts of worker's labial glands in O. formosanus, but there was no significant phagostimulating effect on workers for methanol and hexane extracts of worker's labial glands in O. formosanus. Moreover, the results showed that there was significant repellent effect on workers for distilled water extracts of soldier's labial glands in O. formosanus, and there was neither significant phagostimulating effect nor significant repellent effect on workers for alate's labial glands in O. formosanus.By GC-MS, the results showed that there was no hydroquinone in the distilled water extracts of labial glands and bodies of workers. Furthermore, there were 14 possible phagostimulationg components in the two samples by GC-MS, in which 7 components were contained by the above two samples together, including alanine, L-valine, urea, 4-methoxyphenol, 3,5-dihydroxytoluene, malic acid and sebacic acid. In addition, there was no significant phagostimulating effect on workers of O. formosanus for 1μg/g and 10μg/g hydroquinone; however, there was significant repellent effect on workers of O. formosanus for 50μg/g and 100μg/g hydroquinone.3. Study on feeding and trophallaxis in O. formosanus, using rubidium chlorideDifferences in feeding and trophallaxis among castes of O. formosanus were analyzed using Rubidium (Rb)as a tracer. In the feeding study, workers fed directly on Rb-treated filter paper, and 3rd-instar larvae held the limited feeding ability. Though 5th- and 6th-instar nymphs acquired the marked level of Rb, the feeding ability of the caste was poor. However, Soldiers did not feed on Rb-treated filter paper. In the trophallaxis study, Rb content of worker, soldier and 5th- and 6th-instar nymphal recipients paired with Rb-fed worker donors was significantly higher than that of them paired with control donors respectively. But, Rb content of 3rd-instar larval recipient paired with Rb-fed worker donors wasn't significantly higher than that of it paired with control donors. Moreover, transfer efficiency from the 4 trophallactic combinations was all low.4. Constructing baiting system against O. formosanusThe toxicity results showed that 0.025μg/ml～.4μg/ml fipronil and imidacloprid achieved obvious insecticidal efficacy after O. formosanus were treated for 3 d and 5 d respectively. LC50 of fipronil and imidacloprid for 1 d after treatment were 509 times and 63.8 times as that for 5 d after treatment respectively, indicating that the efficacy of the two pesticides against O. formosanus was slow. The repellent test showed that 50μg/ml fipronil had no obvious repellent effect against O. formosanus, but 50μg/ml imidacloprid had obvious repellent effect.The results of the test on transfer of fipronil among nestmates of O. formosanus showed that mean recipient mortality for 5.0μg/g was significantly than that for 0, 1 or 10μg/g. When donors were treated with 1μg/g fipronil for 1, 6 or 12 h, only mean recipient mortality for 6 h of exposure duration was significantly greater than that of the control during the total test. In addition, mean recipient mortality was evaluated after exposure of 5, 15 or 20 donors to 1μg/g fipronil for 3 h, and the results showed that mean recipient mortality for both 15 and 20 donors were significantly greater than that for the control at 6, 9, and 12 d. Finally, the results indicated that donor workers could not transfer a lethal concentration of fipronil to soldier or larval recipients.The results of the food choice test on O. formosanus showed that in the six diets, the consumption rate, mud sheet area and mud sheet covering rate of the millet powder were maximal. The mud sheet appearing time of the millet powder was only longer than that of the pine powder, but difference between the two diets was not significant. Among the five additives, except for 15% Auricularia auricula, 15% Lentinula edodes, 10% masson pine pollen, 10% white sugar and 15% honey could observably improve the phagostimulating effect of the millet powder on O. formosanus, and the synergistic effect of 10% white sugar was the most distinct in them. The results of the field trial showed that the phagostimulating effect of the baits made of the millet powder+10% white sugar on O. formosanus was better than that of the baits made of the millet powder. To sum up, the millet powder+10% white sugar can be as the diet ingredient of the bait against O. formosanus.Antiseptic effects of 8 mould inhibitors on the millet powder as the preferred diet of O. formosanus were compared. The better mould inhibitors were 0.2% potassium sorbate and 0.075% chlorolthalonil 8 days after treatment in the field. Laboratory experiments showed that 0.2% potassium sorbate had no significant effect on the consumption of the millet powder by O. formosanus, but 0.075% chlorolthalonil significantly reduced the consumption of the millet powder by O. formosanus. Further field results showed that the rate of the bait mould in the CK and bait plus 0.2% potassium sorbate or plus 0.075% chlorolthalonil was 100%, 20% and 30%, respectively, and the rate of bait consumption was 27.67%, 53.70% and 19.15%, respectively, 8 days after the baits were applied. So, 0.2% potassium sorbate can be as mould inhibitor for termite baits.The shaping craft of the termite bait was studied by the handmade molding instrument, and the results showed that bait granularity was the major factor influencing molding status of baits. The best shaping craft of the termite bait of the cane powder was: the thin cane powder, 10% adhesive, 5 s of crush time and 200% water; while the best shaping craft of the termite bait of the pine fritter was: the thin pine fritter, 10% adhesive, 5 s of crush time and 100% water. Termite baits with good molding can be produced by the refitted molding machine, referring to the best molding condition for the handmade molding instrument.5. Application of baiting system against O. formosanusThe results of the field test on decision of toxicant dosage showed that 0.008% fipronil baits induced foraging workers of O. formosanus to die quickly. But 0.002% and 0.004% fipronil baits did not induced foraging workers of O. formosanus to die quickly, and they had the same consumption. So, 0.004% fipronil baits would be used in the test about employing technique of termite baits in the field. Furthermore, the results in the field showed that in the two trial sections of the ground termite gallery means and deadwood-hiding means, the total consumption of fipronil baits was higher than that in the three trial sections of the trapping pit means, means of exposure on the earth's surface and trunk-sticking means. 1 month after the end of applying baits, in the two trial sections of the ground termite gallery means and deadwood-hiding means, the damaged rate of trees reduced 53.57% and 43.24% than that before the treatment respectively, and there were no fresh termite mud sheets in the ground; however, in the three trial sections of the trapping pit means, means of exposure on the earth's surface and trunk-sticking means, the damaged rate of trees increased 16.66%, 17.65% and 2.5% than that before the treatment respectively, and there were many fresh termite mud sheets in the ground. 7 months after the end of applying baits, in the two trial sections of the ground termite gallery means and deadwood-hiding means, the 2 nests of O. formosanus were dead; whereas, in the three trial sections of the trapping pit means, means of exposure on the earth's surface and trunk-sticking means, the 3 nests of O. formosanus were healthy.Triple mark-capture was used to estimate foraging populations and to delineate foraging territories of 4 O. formosanus colonies. Termite activity was monitored by number of termite workers and straw board consumption in underground monitoring stations. Consumptions of bait matrix and fipronil in bait tubes were estimated for each testing site. The results showed that approximately 3～5 mg of fipronil could suppress foraging populations of O. formosanus containing 0.4～0.7 million foragers per colony.
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