Date of Award:

5-1967

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Biology

Department name when degree awarded

Entomology

Committee Chair(s)

William A. Brindley

Committee

William A. Brindley

Committee

D. M. Hammond

Abstract

To determine the effect of the factors of the environment (temperature, relative humidity, and food) on the population growth of Tribolium brevicornis, different levels of temperatures from 17.5°C - 37.5°C were used. Effect of these IeveIs of temperatures was tested upon both pre-embryonic and post-embryonic development. No hatching occurred at 17.5°C, but the threshold temperature (the minimum temperature for the development) was just before 17.5°C. The optimum temperature for the embryonic development was found to be between 32.5°C - 35°C.

With the use of the saturated salt solution according to Buxton (1931) and Buxton and Melanby (1934), certain humidity levels (15, 45, 77.5 and 93 percent relative humidity) were used. These levels of humidities did not seem to have a significant effect on the embryonic development.

The duration of the larval and the pupal stage was determined under three levels of temperature (21.9 ± 1, 27.11 ± 1.2 and 30°C). The shortest duration of larval and pupal stage was found to be under 30°C. The levels of the humidities tested (15, 45, 77.5 and 93 percent relative humidity) upon the duration of larval and pupal stage did not seem to have a significant effect.

Effect of the population densities of the beetles on the cannibalism and the oviposition was tested. The total cannibalism and total oviposition were highly significantly different. The change in rates of oviposition and cannibalism under the densities used (2, 4, 8, 16, 32 and 64 beetles) were not significant, but because of the high standard deviations and coefficient of variabilities the hypothesis (the rate of cannibalism increases with increasing densities, and the rate of oviposition decreases with decreasing densities) were not rejected.

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