Dietary effect of isomers of essential amino acids on the maggots of Dacus cucurbitae (Coquillett)

Dietary effect of the D-isomers of nine essential amino acids was studied on the maggots of Dacus cucurbitae Coq. using a holidic diet. Only arginine was not included. The treatments for each amino acid included replenishment of L-amino acid by its D-enantlomer, DL-racemic mixture, twice DL-mixture, apart from omission of amino acids, individually. The diet containing all L-amino acids constituted the control. Maggot survival and pupation percentage were recorded. The D-isomers of isoleucine, methionine, leucine and lysine apart from histidine, valine and threonine affected the growth and survival of the maggots and all maggots died within six days of inoculating the eggs. D-phenylalanine and D-tryptophan were found to be sparingly utilizable and maggot survived for 10 and 10 days, respectively. DL-isomer of isoleucine, threonine resulted in complete mortality within a fortnight. Tryptophan, valine and phenylalanine were better utilized, while leucine and lysine were among the best utilized amino acid, though only 2 and 4 per cent larvae could pupate. In 2 DL racemic mixture of isoleucine, tryptophan, valine and histidine, the pupatjon was 6, 10, 12 and 14 per cent, respectively.