Bernal-Bautista Manuel Hernando, Turriago-González Jorge Luis, Villa-Navarro Francisco Antonio
Rev Biol Trop. 2017 Mar;65(1):55-63.
Anuran embryos and tadpoles are daily exposed to wide thermal variations in their ponds, with maximum temperatures at midday. The aim of this research was to study the impact of three daily variable thermal environments (with maximum experimental temperatures between 10:00 and 16:00 hours), on the survival, developmental time and body size of metamorphs of four tropical anuran species from lowland habitats in Colombia. A total of 50 embryos (Gosner stage ten) to metamorphosis (Gosner stage 46) of Rhinella humboldti, Hypsiboas crepitans and Engystomops pustulosus were exposed to each one of the three daily variable temperature treatments: high temperature (mean = 27.5 °C; maximum temperature = 34 ± 1 °C; range = 23-35 °C), medium temperature (25.5 °C; 29 ± 1 °C; 23-30 °C), and low temperature (24 °C; 24 ± 1 °C; 23-25 °C). For the other species, Espadarana prosoblepon, 40 embryos to metamorphosis were exposed to each one of the following thermal treatments: high temperature (mean = 22 °C; maximum temperature = 25 ± 1 °C; range = 18-26 °C), medium temperature (20.5 °C; 22 ± 1 °C; 18-23 °C), and low temperature (19 °C; 19 ± 1 °C; 18-20 °C). For all species, the thermal variable environment with the highest temperature showed the greatest accumulated survival, reduced significantly the developmental time from embryos to metamorphs, and the snout-vent-length of metamorphs. Therefore, under field conditions where ponds are exposed to thermally variable environments, the highest temperatures may promote a decrease in the period of time to metamorphosis, and a positive increase for the anuran survival; nevertheless, extreme temperatures were also found in the microhabitat of the species studied, higher than their upper thermal limits reported, which suggest a vulnerable situation for them and other tropical anurans from similar habitats.
无尾两栖类胚胎和蝌蚪每天都会在其栖息的池塘中经历大幅度的温度变化，中午温度最高。本研究旨在探究三种每日变化的热环境（实验最高温度出现在10:00至16:00之间）对来自哥伦比亚低地栖息地的四种热带无尾两栖类幼体的存活、发育时间和体型的影响。将总共50个处于戈斯纳10期的洪氏蟾蜍、鸣声雨蛙和脓疱姬蛙胚胎饲养至变态（戈斯纳46期），分别置于三种每日变化温度处理中的每一种环境中：高温（平均 = 27.5°C；最高温度 = 34 ± 1°C；范围 = 23 - 35°C）、中温（25.5°C；29 ± 1°C；23 - 30°C）和低温（24°C；24 ± 1°C；23 - 25°C）。对于另一种物种，即前口蛙，将40个胚胎饲养至变态，分别置于以下热处理中的每一种环境中：高温（平均 = 22°C；最高温度 = 25 ± 1°C；范围 = 18 - 26°C）、中温（20.5°C；22 ± 1°C；18 - 23°C）和低温（19°C；19 ± 1°C；18 - 20°C）。对于所有物种而言，温度最高的热变化环境显示出最高的累积存活率，显著缩短了从胚胎到幼体的发育时间，以及幼体的吻肛长度。因此，在野外池塘暴露于热变化环境的条件下，最高温度可能会缩短变态所需的时间，并提高无尾两栖类的存活率；然而，在所研究物种的微生境中也发现了极端温度，高于所报道的它们的热上限，这表明它们以及来自类似栖息地的其他热带无尾两栖类处于脆弱状态。
