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The effect of L ‐canavanine and L ‐canaline on the hemolymph amino acid composition of the tobacco hornworm, Manduca sexta (L.) (Sphingidae)
Author(s) -
Lenz Cynthia,
Dahlman D. L.,
Rosenthal G. A.
Publication year - 1986
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.940030305
Subject(s) - manduca sexta , sphingidae , hemolymph , biology , canavanine , ornithine , arginine , biochemistry , amino acid , botany , larva , food science
Tobacco hornworm larvae, Manduca sexta (L.) (Sphingidae), were administered L ‐canaline either by parenteral injection or by dietary consumption. The overt toxicity and the alteration of hemolymph amino acids caused by these nonprotein amino acids were evaluated. The LD 50 value for parenterally administered canavanine and canaline is 1.0 and 2.5 mg/g fresh body weight, respectively. A dietary concentration of 5.2 mM for canavanine and over 20 mM for canaline represent the respective LC 50 values. A large percentage of the larvae reared on diets supplemented with additional arginine, ornithine, or 2,4‐diaminobutyric acid in addition to canavanine or canaline were unable to complete larval‐pupal ecdysis. These toxic effects were associated with a decreased glutamic acid hemolymph titer and dramatically elevated ornithine. On the other hand, larvae administered canavanine or canaline alone, either by dietary consumption or parenteral injection, experienced less drastic developmental aberrations. These symptoms were in some cases correlated with increased ornithine and glutamic acid titers. Evidence is presented that even a canavanine‐ and canaline‐sensitive insect such as M. sexta has a marked ability to eliminate these protective allelochemicals.