Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Baker, Geral T.

Committee Member

Rodriguez, Jose M.

Committee Member

Layton, M. Blake

Committee Member

Willard, Scott T.

Committee Member

Schultz, Tor P.

Date of Degree

12-9-2011

Document Type

Dissertation - Open Access

Major

Entomology

Degree Name

Doctor of Philosophy

College

College of Agriculture and Life Sciences

Department

Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology

Abstract

The overall aim of this study was to provide new and updated information about subterranean termite morphology and digestive physiology. Scanning electron microscopy was used to obtain high resolution images of morphological features of the termite cuticle not discernable by light microscopy. In addition, digital scanning electron micrographs clearly show the appearance of wood particles recovered from the termite digestive tract at different stages of digestion. The ability of termites to obtain and conserve nitrogen in their diet was demonstrated by establishing whether the insect can digest chitin, as well as from determination of levels of soluble proteins and uric acid in the feces. Finally, a technique for determining the efficiency of cellulosic food digestion was tested. Scanning electron microscope images of alate abdomens showed similar appearance of cuticular structures between two subterranean termite species. In addition, the high magnification of electron microscopy allowed for identification of a pair of cuticular structures in the vicinity of the female genitalia that had not been reported from previous light microscope studies. Scanning electron microscopy also revealed the appearance of wood undergoing degradation as it traverses worker termite digestive tract, showing detail not possible from light microscope images. Adult workers of a native termite species were found to produce the enzymes needed to digest chitin, a nitrogen containing polysaccharide ingested by termites. Specific activity of chitinase was subsequently determined to establish the efficiency of chitin digestion for the termite species tested. As termites are coprophagous, significant levels of proteins measured from the feces demonstrated an additional potential dietary nitrogen source. Uric acid was generally found to be absent from termite feces, however. Digestive efficiency of wood cellulose could not be determined for Formosan termites due to the inability to obtain sufficient feces for quantification of undigested food contained in it. Previous studies of Formosan termite digestive efficiency did not address difficulty in obtaining feces for assay. Therefore, interpretation of data from earlier studies of Formosan termite digestive efficiency should be viewed with caution.

URI

https://hdl.handle.net/11668/17081

Comments

termites||chitin||cellulose||protozoa||symbiosis||electron microscopy||nitrogen||digestion

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