Ventricular Esterases: Comparison of Their Distribution within the Larval Midgut of Four Species of Lepidoptera1

Abstract

The midgut tissue of 4 plant-feeding lepidopterous larvae, Diatraea grandiosella, Heliothis zea, Trichoplusia ni , and Pieris rapae , representing three families, was shown to be differentiated into regions which contain varying titers of esterases. Although the highest titer of most esterases was present in the anterior midgut, some esterases were present mainly in the posterior midgut. In the midgut of D. grandiosella 37% of the esterase activity was located in the anterior quarter, 22% in the 2nd quarter, 15% in the 3rd quarter and 26% in the posterior quarter. Corresponding values in H. zea were 27%, 39%, 22%, and 12%. Since the oligophagous D. grandiosella and P. rapae had fewer esterase bands (6-8) than the polyphagous H. zea and T. ni (10-12), the multiplicity of midgut esterases appears to correlate with host specificity.