Epsilon Archive for Student Projects

Abstract

This study was made to compare and distinguish any differences in olfactory recognition and
host plant adaptation between two strains of cotton leaf worm, Spodoptera littoralis. The
populations used were established in Egypt and Benin, Africa. The documentation consisted of
information about (1) each of the strains development through the larval stage up to pupation on
diets of cotton, clover and cowpea. (2) Their oviposition preferences as adults between cotton,
clover, cowpea, maize and cabbage. (3) Electroantennographic recordings to quantify any
possible responses to plant volatiles.
Throughout the diet experiments the larvae from the Benin strain showed significantly a better
development between artificial, clover, cowpea and cotton respectively, while the Egypt strain
had significance between artificial, cotton and cowpea/clover as diet.
Also noted was how the strains substantial development of weight differentiated if fed the cotton
diet, followed by the cowpea diet showing that the Benin strain would develop a higher body
mass on a cotton diet as well as on a cowpea diet.
This trend was however switched once the pupal stage was reached, where the Egyptian strain
contained a significantly greater body mass than the Benin strain on the artificial and the Benin
strain a greater on cowpea, which suggests that in the end, the Benin strain develops significantly
better on cowpea while the Egypt strain develops better on an artificial diet.
During the oviposition experiment that both stains showed a clear difference in hierarchy of host
plants considered suitable for oviposition, where the Egyptian strain is significantly more
attracted to clover than the Benin strain.
Also showed with electroantennographic recordings and significant values was the higher
sensitivity the Egypt strain had towards (E)2-hexenal, (E/Z)-b-ocimene, (Z)-3-hexenyl acetate,
Nonanal, (-)-linalool and β-myrcene when compared to the responses from the Benin strain.