THE ROLE OF NUTRITIONAL FACTORS IN FOOD SELECTION AND PREFERENCE AS RELATED TO LARVAL NUTRITION OF AN INSECT, PSEUDOSARCOPHAGA AFFINIS (DIPTERA, SARCOPHAGIDAE), ON SYNTHETIC DIETS

Abstract

Larvae of Pseudosarcophaga affinis auct. nec Fallén readily discriminated between synthetic diets satisfactory for growth and those that had nutritionally important faults. The faults were lack of an essential amino acid, unsatisfactory ratios of essential and nonessential amino acids, and unsatisfactory proportions of the best amino acid mixture relative to glucose levels. Some of these were made to resemble the proportions of amino acids and glucose found by other workers in tissues of aphid-resistant and -susceptible varieties of peas. All the experiments showed that the diets chosen by larvae were those on which they grew and developed best. That larvae can relate the chemical composition of the selected foodstuff with their nutritional requirements may cast some light on varietal resistance of plants or other foodstuff to insects.