Comparación ontogénica de la frecuencia de muda en Rhinella marina (Anura, Bufonidae)


Iheringia, Sér. Zool.




Molting is a process of constant renewal of the outer layer of epidermis (stratum corneum) in amphibians, which provides a barrier against injury, pathogens and evaporative water loss. This paper evaluates the molting frequency between juveniles and adults of Rhinella marina (Linnaeus, 1758) and between the night and day time. Two daily observations, at 7 am and 7 pm, were made between October 2011 and March 2012 to three groups of individuals, classified by their size, snout vent length, as adults (mean=80 mm), medium juveniles (mean=19 mm) and small juveniles (mean=13 mm). The animals were placed in terrariums in the laboratory and marked on their back with a spot of correction fluid. The molting was determined by the total loss of the mark and a bright color on the dorsal skin. We found a significant difference (Kruskal-Wallis, H=19.84, p<0.0001) in the molting frequency among the three groups: adults=7.5 days, medium juveniles=5.4 days, and small juveniles=5.3 days. Also, between the number of molting frogs during the night and day hours (Chi-square, χ2=7.891, p=0.019), particularly in the two groups of juveniles, who moulted mostly at night, as adults did not show any clear difference. It is possible that the highest molting frequency in juveniles may be related to their ontogenetic status, with a smaller size and higher metabolic and developmental rate.

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