Biodegradation and transfer of ingested 2,4-D herbicide by a polyphagous saturniid caterpillar

A herbicide containing 2,4-dichlorophenoxyacetic acid (2,4-D) and related c hemicals was fed to caterpillars of Eupackardia calleta, and the fate of th e substances in the larvae and during further ontogenesis was followed by c ombined gas chromatography/mass spectrometry. The compounds were found in d iffering amounts in larval midgut, faeces, fat body/haemolymph, and even in an exocrine secretion produced by integumental glands. Furthermore, they w ere detected in samples from the resulting adult moths, indicating an intra individual transfer. Since the individual development of E calleta was dist inctly accelerated by 2,4-D, possible impacts of the herbicide on the life history of the animals in the field are discussed. Based on the chemical da ta, hypothetical metabolic pathways for 2,4-D in E. calleta larvae are prop osed. (C) 2001 Elsevier Science Ltd. All rights reserved.