Relationship of free amino acids of some solanaceous plants to growth and development of Leptinotarsa decemlineata (Coleoptera: Chrysomelidae).

Beginning at hatching, larvae of the Colorado potato beetle, Leptinotarsa decemlineata (Say), were fed young, bloom-stage, and senescent foliage of 4 solanaceous plants, namely, potato, eggplant, horse-nettle, and 4 varieties of tomato. Under laboratory rearing conditions, larvae completed their growth most rapidly on young foliage of potato, while larval stadia were prolonged for those fed some of the other plants, especially the senescent plants. Percent survival from first-instar larvae to adults was relatively high for all that had fed on the potato foliages, young eggplant, and bloom-stage Rutgers tomato, but was extremely low for those fed senescent foliage of the tomato varieties. Average adult weights were higher for those that had fed as larvae on foliages of potato and bloom-stage Rutgers tomato, lowest for those reared on young eggplant foliages. Ethanol extracts were made of the several kinds of foliages, and the free amino acid composition of the extracts was checked by 1- and 2-way paper chromatography. Extracts of young potato foliage contained the greatest variety of amino acids, and all potato foliages contained all the essential amino acids. Threonine and tryptophan were absent from other extracts. The most prominent amino acids and amides in all the plant extracts were glutamic acid, serine, aspartic acid, alanine, glutamine, and gamma aminobutyric acid.