Garotenoids and colouration of poplar hawkmoth caterpillars (Laothoe populi) |
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Authors: | JOY GRAYSON MALCOLM EDMUNDS E. HILARY EVANS GEORGE BRITTON |
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Affiliation: | Department of Applied Biology, Lancashire Polytechnic, Preston PR1 2TQ;Department of Biochemistry, University of Liverpool, P.O. Box 147, Liverpool L69 3BX |
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Abstract: | Carotcnoids and chlorophylls a and b were extracted from final instar caterpillars of the poplar hawkmoth ( Laothoe populi ) and the eyed hawkmoth ( Smerinthus ocellata ), as well as from their food plants. Both species of caterpillar absorb the two chlorophylls and the carotenoids lutein, cis -lutein and β-carotene in the gut and deposit lutein and cis -lutein in the integument. It is the lutein, together with pterobilin, that is largely responsible for the colour of the insect: yellow-green poplar hawkmoth caterpillars have more lutein in the integument than dull green ones which in turn have more than white ones. Yellow-green and dull green caterpillars both sequester lutein and cis -lutein in the gut wall, but the yellow-greens translocate more of these pigments to the integument than the dull greens. The white caterpillars absorb very little lutein and cis -lutein into the gut, and so they have much less also in the integument. The mechanism by which the reflected light perceived by the caterpillar is translated into differential absorption of pigment by the gut and deposition in the integument is not known. |
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Keywords: | Carotenoids chlorophyll lutein colouration Laothoe populi hawkmoth caterpillars plant pigment sequestration |
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