Relationship between Plastron Color and Nutrition in Pseudemys nelsoni Carr, 1938

Abstract

Body coloration of emydids can be triggered by different types of factors. Therefore, the current study aimed to investigate the changes in plastron color of Florida Red-bellied Turtle Pseudemys nelsoni (P. nelsoni Carr, 1938), an emydid of North America. In the current study, 15 (3 males and 12 females) fresh corpses of captive-reared adult specimens of P. nelsoni were analyzed using digital images as well as applying geometric morphometrics and color photo processing techniques. Plastron color had no relationship with size nor fluctuating asymmetry, which could be considered as a negative proxy for stress. Moreover, there were no significant differences between males and females in this regard. It can be suggested that reddish on plastron for P. nelsoni was highly related to feeding, compared to other external factors, such as age, size, or stress. In wild P. nelsoni populations, reddish plastral coloration was related to body size probably due to ontogenetic differences in the diet, as juveniles are omnivorous. Since adults are herbivores, reddish fading observed in the samples of the current study would be a mere expression of unnatural colors, which can probably be linked to unbalanced feeding. The results of the current research could contribute to the understanding of the ways color changes appear in captive turtles in response to differences in dietary access to carotenoids.