Date of Award

2000

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Entomology

First Advisor

Gregg Henderson

Abstract

A laboratory study was conducted to investigate the effects of sibship patterns and different origins of colonies on mate mortality and growth of incipient colonies in the subterranean termite, Coptotermes formosanus Shiraki. Primary reproductives from New Orleans in nonsibling pairs had significantly higher mortality than sibling pairs. The average egg production for sibling and nonsibling pairs showed no overall significance in the first oviposition period, however, the average number of larvae was consistently higher in nonsibling than in sibling-founded colonies from New Orleans. After two years, the average number of eggs or larvae present in nonsibling-founded colonies was significantly higher than sibling-founded colonies from New Orleans. Colonies headed by sibling pairs from Lake Charles showed the highest number of larvae. Either sibling- or nonsibling-founded colonies from Lake Charles had a significantly higher survival rate than colonies from New Orleans. The high mortality of outbred pairs may be an effect of outbreeding depression or disease. The heterozygous offspring by outbred pairs may provide advantages to environmental fluctuations and harbor greater protozoan populations. Differences on survival and production of brood between two areas may represent regional preadaptations. In a second series of tests, it was determined that termite survival and wood consumption were affected by a complex of factors. Termite cohort at 30°C with initial soldier proportions of 0 up to 10% produced a higher soldier proportion than those at 20, 25, or 33°C. There was a significant interaction of temperature by soldier proportion on termite survival. These two variables could not be isolated in our termite bioassay. C. formosanus did not significantly increase wood consumption rate as termite density increased. Termite survival and wood consumption rate declined significantly when termite exceeded a density >300 individuals. Termite survival and wood consumption rate significantly increased as wood volume increased. However, there was no significant influence of wood surface area on consumption rate and survival, given a constant wood volume. Moisture is a precondition for colonization by C. formosanus queens and kings. Nitrogenous compounds of urea or L-glutamic acid in the moist substrate did not increase nest site preference.

ISBN

9780599853171

Pages

119

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