Journal of Chemical Ecology (2002) 28, 1365-1375

J.A. Cianfrogna, A.R. Zangerl and M.R. Berenbaum (2002)
Effects of furanocoumarins on feeding behavior of parsnip webworms Depressaria pastinacella
Journal of Chemical Ecology 28 (7), 1365-1375
Abstract: The parsnip webworm, Depressaria pastinacella, exhibits limited physiological resistance to furanocoumarin toxins in its principal host, the wild parsnip, Pastinaca sativa. These insects are typically found attacking individual plants low in furanocoumarins, relative to others within populations. They also feed preferentially on parthenocarpic fruits, which are lower in furanocoumarin content than are normal fruits. However, in a previous study with artificial diets, they did not appear to discriminate between high and low concentrations of furanocoumarins. In this study, the ability of webworms to distinguish between diets differing in furanocoumarin content was examined with an artificial diet containing wild parsnip and in green parsnip fruits with and without supplemental furanocoumarins. Larvae showed no preference for high or low furanocoumarin diets containing equal amounts of freeze-dried parsnip fruit powder. When given a choice between otherwise similar wild parsnip fruits, webworms strongly preferred fruits that were not augmented with furanocoumarins in one plant but showed no preference or only a weak preference for nonaugmented fruits in four other plants. In order to identify chemical constituents other than furanocoumarins that might determine feeding preferences, we compared the chemical profile of parthenocarpic fruits (which are preferred) to that of normal fruit. Octyl butyrate, a known deterrent to webworms, is highly correlated with furanocoumarin content, occurs in all plants, and differs significantly among normal and parthenocarpic fruit, suggesting that webworms may be able to avoid furanocoumarins by virtue of their behavioral response to octyl butyrate.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): May R. Berenbaum

Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Depressaria pastinacella	Parsnip (Pastinaca sativa)