Specific Accumulation of Lutein within the Epidermis of Butterfly Larvae - Carotenoids: Physical, Chemical, and Biological Functions and Properties - page 531

435 nm

0.009

0.007

0.005

0.003

0.001

350 400 450 500 550

(a)

Wavelength (nm)

Scan AP+
3.48e3
Cone voltage 5

391.3;3479

100

Parent and principle ions
M +1

%

15 10'

O

10 15'

HO

0

m/z

(b)

300 325 350 375 400 425 450 475 500 525 550 575 600 625 650 675 700 725 750

-apo-b-carotenal obtained during elution; and
(b) the mass spectrum shows a single major peak, the principle ion ( M + 1, 391 e / z ) matching that of the
expected C 27 H 35 O 2 chemical formula.

FIGURE 25.5 (a) The UV/visible spectrum of 3-hydroxy-10 ′

found in those of the Monarch. Remarkably, the Atala has much higher concentrations of lutein in
all regions than the other species investigated in this study.

25.4 DISCUSSION
The presence of high concentrations of lutein and the striking absence of measurable quantities of
other carotenoids in the yellow bands of the Monarch larvae as well as those of other species coni rm
that the coloration in these yellow pigmented regions results from a localized, specii c lutein accu-
mulation. Analysis of food-plant extracts showed that numerous carotenoids, in addition to lutein,
are abundant in the diet of these larvae, including zeaxanthin, xanthophyll epoxides, and b-carotene,
Figure 25.3b. A comparison of the chromatogram of the leaf extracts with that obtained from the
larvae shows that lutein in the epidermis extracts is dramatically enriched relative to zeaxanthin
and that the other carotenoids are undetectable. The presence of small but readily measured levels
of lutein (but not other carotenoids) in other colored regions suggests that its presence, albeit at low
levels, in these regions could serve a photoprotective function throughout the epidermis. Notably,
the accumulation of carotenoids by parsnip webworms serves to protect them from photosensitized
damage during the exposure to UV light (Carroll and Berenbaum 2002). Considerable data demon-
strate that even low levels of carotenoids are effective at protecting the epidermis from light-induced