Food-dependent color patterns in Thamnocephalus platyurus Packard (Branchiopoda: Anostraca); a laboratory study

Abstract

Coloration of phyllopods varies from place to place and from one life stage to another. It ranges from translucent or whitish through gray, blue, green, orange, and reddish. Here, we present experimental evidence for a food-dependent color pattern in Thamnocephalus platyurus Packard. The presence or absence of the synthetic pigment trans-β-carotene in a baker’s yeast diet was the controlling factor. All the 24 old larvae used in the experiment were whitish in color. From day 6 until the end of the experiment (day 11), 100% of the shrimps under a diet with synthetic trans-β-carotene (treatment 1) exhibited a characteristic color pattern which consisted of an orange color in the cercopods, and in all thoracopods; the rest of the body exhibited no particular color. In comparison, 100% of the shrimps under a diet without synthetic trans-β-carotene (treatment 2) were whitish throughout the body. In females from treatment 1, the ovaries and oocytes were green-bluish, while in females from treatment 2 the ovaries and oocytes were whitish. No significant differences in survival and growth were found, except that at day 9, there was a significant difference in growth, the females with the synthetic trans-β-carotene group growing faster.Key wordsβ-carotenebaker’s yeastgrowthsurvival