Effects of calcium and glutamate receptor agonists on leaf consumption by lepidopteran neonates

Calcium and glutamate receptor (GluR) agonists affect apple leaf consumption by neonates of the apple pest, the codling moth, Cydia pomonella (L.) Initial apple leaf consumption was advanced by the presence of trans-1-amino-(1S,3R)-cyclopentanedicarboxylic acid (trans-ACPD), but not by calcium chloride or N-methyl-D-aspartate (NMDA). However, during the 3 h following hatch, CaCl(2) and NMDA increased the quantity of apple leaf tissue consumed, but trans-ACPD had no such effects. Stimulatory effects of CaCl(2) and NMDA on leaf consumption were abolished if codling moth larvae were concurrently exposed to calcium chelator EDTA. (RS)-alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropanoic acid (AMPA) and kainic acid had no effects either on commencement or intensity of leaf consumption. We hypothesize that in codling moth larvae, apple leaf consumption is induced via metabotropic GluR, and sustained feeding is regulated via NMDA GluRs. Practical aspects of this finding are discussed.