The effect of different UV and calcium provisioning on health and fitness traits of red-eyed tree frogs (Agalychnis callidryas)

Abstract

In response to global amphibian declines and extinctions, the IUCN has recommended the establishment of ex situ conservation breeding programmes. However, there are a limited number of studies that scientifically assess amphibian husbandry practices, even at a basic level of nutrition and lighting. One component of captive husbandry that is increasingly discussed is the provision of ultraviolet radiation (UVR), which is required for the synthesis of vitamin D3 and subsequent assimilation of calcium and phosphorous from the diet. Here we used two methods of UV provision (“background UV” and “background UV with UV boost”) and two calcium gut-loading diets (5% and 10%) to assess the effects on a range of fitness measures in the red-eyed tree frog (Agalychnis callidryas). We found no effects of either UV treatment or calcium diet on growth, body condition or cutaneous bacterial communities of frogs, although subsequent to the UV boost, frogs had a significantly greater fungal load in comparison to frogs that were not UV-boosted. There were negligible differences in the breeding success of females according to UV exposure. Provision of the UV boost was not demonstrated to provide any real advantages for A. callidryas in terms of growth or breeding success. In addition, there were no benefits of a 10% calcium diet over a 5% calcium diet (in conjunction with regular dusting). Further studies that investigate the UV requirements of other amphibian species and ecotypes are required, particularly in conjunction with naturalistic cricket gut-loading diets.