The nutrition of the larva of Aëdes aegypti Linnaeus. 4. Protein and amino-acid requirements

Abstract

In a medium complete in other respects, but lacking protein,the mosquito larva does not grow to the 2d instar. After yeast, casein is the most suitable protein, but incomplete proteins, on supplementation with amino acids, prove adequate for growth and survival to the adult stage. Good rates of growth and survival could be produced by using mixtures of amino acids, but variation in their relative proportions or reduction in the number of amino acids had adverse effects. By omitting single amino acids from a mixture, it was possible to establish that the following are essential for the mosquito larva; glycine, L-leucine, DL-isoleucine, L-histidine, L-arginine, L-lysine, L-tryptophan, DL-threonine, DL-phenylalanine and DL-methionine. The status of DL-valine could not be determined while using yeast autolysate in the medium. There was evidence that the omission of L-cystine resulted in a high proportion of adult mosquitoes failing to emerge. According to the level of phenylalanine or tyrosine in the medium various shades of pigmentation could be produced in the mosquito larvae. The adults emerging even from wholly unpigmented larvae were normally pigmented and there appeared to be little relation between pigmentation and growth or survival. A number of compounds were found capable of producing intermediate degrees of pigmentation in the mosquito larva.