Identifier

etd-11082011-160845

Degree

Doctor of Philosophy (PhD)

Department

Biological Sciences

Document Type

Dissertation

Abstract

In the interest of developing environmentally friendly interventions to infestations by Formosan subterranean termites, Coptotermes formosanus Shiraki, a number of carbohydrates were tested for effects on termites and symbionts. Among these, the D-galactose analog, 2-deoxy-D-galactose, myo-inositol and its fully phosphorylated derivative, phytate, showed promise as potential control chemicals. Feeding bioassays with 20 termite workers, where compounds were applied (concentrations ranged from 160.2-1281.7 µg/mm3) to 5 cm filter paper in water, indicated all three compounds significantly impact termite mortality in a dose dependent fashion over a 2 wk period. Interestingly, when myo-inositol was administered to termites in agar (40 mg/mL), in the absence of a paper food source, its toxic effect was abolished, while 2-deoxy-D-galactose toxicity remained, suggesting myo-inositol’s mechanism of toxicity may involve disruption of cellulose digestion and 2-deoxy-D-galactose may poison the termite directly. Myo-inositol feeding bioassays were also conducted with red imported fire ants, Solenopsis invicta Buren, who appeared immune to the toxic effect. Radiotracer feeding studies involving myo-inositol-[2-3H] and worker termites indicated myo-inositol is not chemically changed following its ingestion. When the hindgut protozoa of termites feeding on myo-inositol and 2-deoxy-D-galactose were quantified decreased populations were observed. Myo-inositol, phytate and 2-deoxy-D-galactose all take approximately one week to induce mortality, indicating that they may have promise as a delayed action toxins, which, if added to baits, could allow time after bait discovery for an entire colony to be affected.

Date

2011

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Laine, Roger A.

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