Nutrition of the European Corn Borer, Pyrausta nubilalis (HBN.). II. Some Effects of Diet on Larval Growth Characteristics

Abstract

European corn borer larvae were reared on purified diets under aseptic conditions. A study was made of the effects of omitting single constituents from the diet. It was found that the omission of either brewer''s yeast powder or lipids resulted in a suppression of growth and molting. The omission of either casein or glucose partially suppressed growth and molting. Omission of a source of an unidentified growth factor found in corn leaves resulted in poor growth, but the larvae molted normally. From head-width and wt. measurements of the larvae on the various diets, an allometric relationship between these two dimensions was demonstrated. Diets causing sub-optimal growth in terms of wt. also caused sub-opt. growth in terms of head-width. Head-width progression factors were not constant from molt to molt, but they declined in value from the 2d molt and reflected differences caused by dietary conditions. From the data presented and from a consideration of literature, it was concluded that Dyar''s Rule has no fundamental basis.