Biology of a local population of Chilo suppressalis (Walker) evaluation of the toxicology and feeding response to Bacillus thuringiensis cry IC endotoxin

Date

4-1993

Degree

Bachelor of Science in Biology

Major Course

Major in Cell Biology

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Cesar G. Demayo

Abstract

Developmental biology and behavior and growth response to Bacillus thuringierlois Cry IC of chilo suppressalis was investigated. Larval development time showed significant differences between sexes and populations, with sex causing the variability within and between populations. Pupal development time are equal on both sexes indicating that sex does not influence the development of the insect in the pupal stage. Total development time showed to he significantly different between sexes sugggesting that sex is a factor on the total development time of an insect. G-test was used to show if the populations of C. suppressalis deviates from the 1:1 ratio.Hybridization showed that the population does not follow the 1:1 ratio. Toxicity of CryIC was determined exposing the neonates in a No Choice Test and showed variable responses of the insect. Behavioral response was observed by exposing the neonate to Choice Test and the neonates showed avoidance to the diet containing the toxin. Lethal doses of Cry IC was determined using Probit Analysis. Third instar larvae forced fed with different concentrations of Cry IC showed an increase in weight after 7 days and prolonged larval stage. Insects that were able to proceed to the pupal stage and later the adult stage showed abnormalities. Although Cry IC does not exhibit a knockdown effect, it prolongs the development of C. suppressalis at the stage where it is most vulnerable.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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