Hampea sp., Host of the Boll Weevil.1 II. Laboratory Antibiosis Studies 2,3

Abstract

Anthonomus grandis Boheman developmental studies were conducted on diets of freeze-dried cotton buds, Gossypunn hirsutum L., and buds and capsules of Hampea sp., a dioecious host, using the laboratory strain of weevils and a wild strain collected from Hampea. A high degree of larval antibiosis was found in Hampea . It was more pronounced in female buds and capsules than in male buds. On diets from male buds and female buds and capsules, smaller adults and a longer developmental time were observed. However, the percent adult emergence of the laboratory, but not the Hampea strain of weevils, from male bud diets was about equal to cotton diets. In the female buds and capsules the antibiosis was also expressed as high larval mortality. The 2 strains of weevils were physiologically different in their growth and development on all diets. Quantitative chemical analysis of gossypol, ascorbic acid, total sugars, and reducing sugars in the male and female buds and capsules failed to show that any of these materials except possibly gossypol was related to the expressed resistance. Thus, some unknown toxic factor rather than nutrition is suspected as the cause of antibiosis.