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Science 11 July 1986:
Vol. 233. no. 4760, pp. 221 - 223
DOI: 10.1126/science.233.4760.221
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Articles

A Toxic Dipeptide from the Defense Glands of the Colorado Beetle

D. DALOZE 1, J. C. BRAEKMAN 1, and J. M. PASTEELS 1

1 Collectif de Bio-écologie, Faculté des Sciences, C.P. 160, Université Libre de Bruxelles, Avenue F. D. Roosevelt, 50, 1050 Bruxelles, Belgium.

The Colorado beetle is protected against predators by the secretions of defensive glands located on the pronotum and the elytra. The single major compound of the secretion was identified as ggr-L-glutamyl-L-2-amino-3(Z),5-hexadienoic acid by spectroscopic and chemical methods. This compound, which contains a nonprotein beta,ggr- unsaturated amino acid, is toxic to ants (Myrmica rubra) at a concentration 10-2 molar, which is less than its estimated concentration in the secretion (1.8 x 10-1 molar).

Submitted on December 19, 1985
Accepted on March 24, 1986

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Science. ISSN 0036-8075 (print), 1095-9203 (online)