Disposition of Cucurbitacin as a Factor in Host Plant Selection by Diabroticite Beetles and Electrophoretic Analysis of the Coevolved Genus Cucurbita
Five species of Diabroticites with different host plant affinities produced an essentially identical array of metabolites when fed radio-labeled cucurbitacin B. All species excreted the bulk of the cucurbitacin (67.17-94.59% total dpm); permanently sequestered a small proportion of a cucurbitacin D conjugate in the hemolymph (0.98-2.76%); and apportioned the remainder between the gut, the body and the eggs (when present). Markedly different ratios between the excretory metabolites, i.e., polar vs. unmetabolized cucurbitacin, suggest that Diabrotica virgifera virgifera, a grass specialist, and Acalymma vittatum, a cucurbit specialist, have lower rates of metabolic alteration than D. undecimpunctata howardi and D. balteata which are polyphagous and D. cristata.
University of Illinois - Urbana-Champaign
Networked Digital Library of Theses and Dissertations
University of Illinois at Urbana-Champaign