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A novel defaunation method of the protozoa to investigate cellulose metabolism in Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae)
1994 - IRG/WP 94-10050
The largest protozoa in the hindgut of workers of Formosan subterranean termite, Coptotermes formosanus Shiraki, was selectively eliminated by forced-feeding on low-molecular weight cellulose (LC) with a mean DP of 17. Although one week's feeding on LC caused perfect disappearance of Pseudotrichonympha grassii Koidzumi, the selective defaunation method itself had no detrimental effect on the health conditions of termite on the basis of survival rates and weight changes of workers in the latter feeding. In addition, the fact that the defaunated workers repidly recovered their wood-attacking activity by being mixed with normally faunated workers could well support this assumption. By the results of changes of protozoan fauna when selectively defaunated workers were forced to feed on various cellulose substrates, it was suggested that each protozoan species had its inherent role in cellulose metabolism.
T Yoshimura, K Tsunoda, M Takahashi


Biological resistance of phenol-resin treated wood
1990 - IRG/WP 3602
Biological resistance of PF (phenol formaldehyde resin) - treated wood has been tested in relation to the resin properties, wood species and biological factors. When tested using water-soluble PF (mol. wt. 170), ca. 10% RI (resin impregnation) was enough to suppress the decay of Japanese cedar (Cryptomeria japonica) and western hemlock (Tsuga heterophylla) blocks exposed to Tyromyces palustris (brown-rot type) and Coriolus versicolor (white-rot type). For a decay suppression of Japanese beech (Fagus crenata) by treating with the same PF, ca. 20% RI was required for both cases of exposure. When using ethanol-soluble PF (mol. wt. 300), the lesser effect on decay suppression was revealed for most of wood-fungus combinations, suggesting a possible better penetration of lower molecular resin into the wood cell walls. PF treatment of wood also affected the termite Coptotermes formosanus, causing the severe depletion of feeding activity and the higher mortality at 5-15 (%) RI. Of the three species of symbiotic protozoa, the most cellulolytic Pseudotrichonympha grassii diminished first shortly after feeding.
M Takahashi, Y Imamura


Distribution of the three symbiotic protozoa in Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae)
1993 - IRG/WP 93-10010
Six colonies (three each from laboratory and field) of Formosan subterranean termite, Coptotermes formosanus Shiraki, were served for investigating the abundance and distribution of three symbiotic protozoa in the hindgut of workers. The total protozoan number amounted to 6,000-10,000 per a worker, and the order of the abundance of the three protozoa and the proportional distribution of each species in the hindgut were common among the colonies. Pseudotrichonympha grassii Koidzumi was the smallest in number (800-2,200 per a worker) and was preferentially distributed in the anterior part of the hindgut. Holomastigotoides hartmanni Koidzumi was medial in number (1,200-3,000), and the distribution was relatively uniform all through the hindgut. Spirotrichonympha leidyi Koidzumi was the most abundant in number (2,800-5,000) and was found mainly in the posterior part. These results appeared to support that the prominent localization of each protozoan species in the worker´s hindgut could be related to the nutritional metabolism in Coptotermes formosanus.
T Yoshimura, K Tsunoda, M Takahashi


The effect of boric acid on the protozoan numbers of the subterranean termite, Reticulitermes lucifugus
1996 - IRG/WP 96-10148
Lower termites harbor in their guts populations of microorganisms known to be indispensable for their survival, being responsible, at least partially, for the digestion of cellulose, the main item of termites'diet. The Reticulitermes species in particular harbor in their hindguts some unique intestinal fauna, for instance protozoa belonging to the genera Pyrsonympha, Dinenympha and Trychonympha. The effect of boric acid on these organisms was evaluated by direct enumeration of the total number of protozoa and the number of most relevant protozoa genera. Although there is a clear effect of the boron on the protozoan populations, the actual decrease in total numbers is not very great, and only one group of the larger protozoa (Trychonympha) tended to disappear with the increasing concentrations of active ingredient.
L Nunes, D J Dickinson


Detrimental effects of boric acid on symbiotic protozoa in Reticulitermes flavipes (Kollar) and Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae)
2000 - IRG/WP 00-10366
In laboratory choice bioassays, Reticulitermes flavipes (Kollar) and Coptotermes formosanus Shiraki were offered a tunneling soil consisting of boric acid (BA) mixed with sterilized soil at concentrations of 0.05, 0.25, 0.50, 1.00, 2.00, or 4.00 percent AI (wt:wt). Termites could choose to remain in their main nest that contained non-treated artificial substrate and adequate food, or tunnel through BA-treated soil in an attached foraging tube to reach a satellite nest that also contained non-treated artificial substrate and additional food. Gut protozoa populations were determined after 12 weeks. Termite tunneling through BA -treated soil resulted in moderate reduction to complete loss of symbiotic gut protozoa in both termite species as BA increased to the greatest concentration. Reductions in protozoa were most noticeable in the 2.00 and 4.00 percent BA concentrations. Boric acid was not repellent and termites removed BA-treated soil from foraging tubes and deposited it in main and satellite nests. Generally, at BA concentrations of 1.00-2.00% or less in soil, termite gut protozoa populations did not appear to be dose dependent. The four primary protozoa genera in R. flavipes and the three primary protozoa genera in C. formosanus were all detrimentally affected by exposure to BA. Overall, BA mixed in soil caused significant loss of protozoa that was very detrimental to both termite species.
B M Kard


Transfer of Termiticidal Dust Compounds and their Effects on Symbiotic Protozoa of Reticulitermes flavipes (Kollar)
2008 - IRG/WP 08-10661
Dusting of termites in situ has been used as a control measure for decades; however environmental awareness of the toxicity of certain compounds now limits their use (eg arsenical dusts). Our laboratory is in the process of suppressing an isolated colony of Reticulitermes flavipes (Kollar) from a small village of 250 homes in mid-central Wisconsin (Endeavor, WI). Initial treatment of the colony involved the use of 200 Microgen bait cartridges containing 0.25% diflubenzuron. The presence of many living termites occupying bait stations throughout the season prompted the addition of various dusting compounds, such as boron, N-N’naptahaloylhydroxylamine (NHA) and other dusts to aide in colony elimination. This laboratory study explores the efficacy of various insecticidal dusts to kill termites as well as to transfer the insecticide to nest mates. Mortality after primary (direct) dusting was found to occur with sodium borax, zinc borate, concrobium polymer (CP) and NHA in 7, 9, 9 and 21 days respectively. However, the ability to cause mortality to 25 un-dusted termites was impaired in the concrobium group and delayed in others. Further tests were performed to determine the mechanism of transfer by examining the survival rates of the symbiotic flagellated protists in the termite hindgut over time after dusting to determine if termiticidal dusts were killing the protozoa necessary for cellulose digestion. Possible mechanisms of mortality are discussed as well as the potential of using dusting compounds in termite treatment or eradication.
F Green III, R A Arango, G Esenther