Amino acid requirements of the mosquito Culex pipiens: Asparagine essential

Abstract

When any of the ten “rat essential” amino acids was omitted singly from a fully-defined synthetic dietary medium, newly-hatched Culex pipiens larvae were unable to develop to the second instar. With proline omitted, development was greatly retarded and survival to the adult stage reduced. Without aspargine (but not aspartic acid) growth and development ceased in most individuals before larval-pupal ecdysis, and no adults were obtained. These twelve amino acids are considered nutritionally essential for this mosquito. With glycine omitted singly, development was markedly retarded, but survival to the adult stage was not affected; thus this amino acid is required for good growth, but these experiments do not demonstrate it as essential. Single omission of alanine, aspartic acid, cysteine, glutamic acid or amide, serine or tyrosine had virtually no effect on development and they are therefore considered nutritionally non-essential. With diets containing the twelve culex-essential amino acids only, very little development occurred, but augmentation with either glycine or serine allowed growth and development almost as good as with the complete amino acid mixture. Augmentation of the essential twelve with alanine, cysteine, glutamic acid/amide, or tyrosine singly failed to improve development. The requirement for dietary asparagine shown by these studies appears to be unique among insects so far studied. In particular, another mosquito, Aedes aegypti, has no such requirement.