| Abstract: | When precocene II was fed to last instar larvae of Heliothis zea, it caused significant reductions in the calculated rate of growth, rate of nutrient assimilation, and conversion of ingested and digested food to body mass. No change in the rate of food consumption occurred but respiration was significantly higher. Transport of the nutrient 1-14C] linoleic acid across midgut tissue was hindered when larvae were fed precocence II. There was also a precocene-induced change in the apical (luminal) morphology of midgut cells, including absence of the glycocalyx and loss of the microvillar absorptive surface. The influence of precocene II on the midgut physiology and metabolic processes in last instar larvae of H. zea may account for the observed reduced growth and delayed development. © 1992 wiley-Liss, Inc. |
