TY - JOUR
T1 - Carotenoid deprivation and beta-carotene's effects on male and female turtle color
AU - Steffen, John E.
AU - Quigley, Rhett
AU - Whibley, Ian
AU - McGraw, Kevin J.
N1 - Funding Information:
JES is indebted to Robert Warburton and Coleen Nolan for establishing the SOARs scholarship program which provided financial support to RQ and IW. JES would like to thank LA for the painted turtle photo, SH for reading and offering comments on an early draft of this manuscript, and the CBPB reviewers and editor for their revision suggestions. Finally, JES would like to thank the many Shepherd University students who helped feed turtles and clean turtle tanks throughout the study.
Publisher Copyright:
© 2020
PY - 2021/4/1
Y1 - 2021/4/1
N2 - Carotenoid-colored integuments commonly function as sexually selected honest signals because carotenoid pigments can be costly to obtain, ingest, absorb, metabolize or transport before being deposited into the integument. As such, carotenoid pigmentation is often sexually dichromatic, with males being more colorful than females. Sexual dichromatism may also occur in ultraviolet (UV) wavelengths, which is visible to organisms who possess UV-sensitive photoreceptors. The stripes and spots of painted turtles (Chrysemys picta) are carotenoid-based and reflect UV wavelengths. This research describes UV sexual dichromatism in painted turtles and shows how carotenoid deprivation changes spot and stripe color in male and female painted turtles. Adult turtles were fed a diet that was supplemented with carotenoids (i.e., C diet) or deprived of carotenoids (C-). Stripe and spot color were measured with UV–vis spectrometry, and blood was drawn from all turtles before and after the dietary treatment. HPLC analysis revealed five carotenoids (4 xanthophylls and beta-carotene) circulating in turtle blood. C-diet reduced yellow chroma and increased brightness of yellow and red stripes or spots, relative to the C diet, but there was no sexually dimorphic effect of carotenoid deprivation on color, nor did carotenoid deprivation affect UV reflectance. Carotenoid deprivation reduced all circulating carotenoids, but beta-carotene was the only pigment with a significant effect on post-experimental carotenoids, implying that changes in color were due in part to reduction in circulating levels of beta-carotene. Color generation appears to be complex in turtles and have dietary as well as non-dietary components.
AB - Carotenoid-colored integuments commonly function as sexually selected honest signals because carotenoid pigments can be costly to obtain, ingest, absorb, metabolize or transport before being deposited into the integument. As such, carotenoid pigmentation is often sexually dichromatic, with males being more colorful than females. Sexual dichromatism may also occur in ultraviolet (UV) wavelengths, which is visible to organisms who possess UV-sensitive photoreceptors. The stripes and spots of painted turtles (Chrysemys picta) are carotenoid-based and reflect UV wavelengths. This research describes UV sexual dichromatism in painted turtles and shows how carotenoid deprivation changes spot and stripe color in male and female painted turtles. Adult turtles were fed a diet that was supplemented with carotenoids (i.e., C diet) or deprived of carotenoids (C-). Stripe and spot color were measured with UV–vis spectrometry, and blood was drawn from all turtles before and after the dietary treatment. HPLC analysis revealed five carotenoids (4 xanthophylls and beta-carotene) circulating in turtle blood. C-diet reduced yellow chroma and increased brightness of yellow and red stripes or spots, relative to the C diet, but there was no sexually dimorphic effect of carotenoid deprivation on color, nor did carotenoid deprivation affect UV reflectance. Carotenoid deprivation reduced all circulating carotenoids, but beta-carotene was the only pigment with a significant effect on post-experimental carotenoids, implying that changes in color were due in part to reduction in circulating levels of beta-carotene. Color generation appears to be complex in turtles and have dietary as well as non-dietary components.
KW - Beta-carotene
KW - Color
KW - Diet
KW - Sexual dichromatism
KW - UV
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U2 - 10.1016/j.cbpb.2020.110546
DO - 10.1016/j.cbpb.2020.110546
M3 - Article
C2 - 33346113
AN - SCOPUS:85098705329
SN - 1096-4959
VL - 253
JO - Comparative Biochemistry and Physiology Part - B: Biochemistry and Molecular Biology
JF - Comparative Biochemistry and Physiology Part - B: Biochemistry and Molecular Biology
M1 - 110546
ER -