The impact of egg incubation temperature on the personality of oviparous reptiles

Personality traits, defined as differences in the behavior of individual animals of the same species that are consistent over time and context, such as ‘boldness,’ have been shown to be both heritable and be influenced by external factors, such as predation pressure. Currently, we know very little about the role that early environmental factors have upon personality. Thus, we investigated the impact of incubation temperature upon the boldness on an oviparous reptile, the bearded dragon (Pogona vitticeps). Eggs, from one clutch, were incubated at two different average temperatures within the normal range. After hatching the lizards were raised under the same environmental conditions. Novel object and novel environment tests were used to assess personality. Each test was repeated in both the short term and the long term. The results revealed that incubation temperature did impact upon ‘boldness’ but only in the short term and suggests that, rather than influencing personality, incubation temperature may have an effect on the development of behavioral of oviparous reptiles at different stages across ontogeny.

动物个性特质（personality traits）被定义为同一物种不同个体间存在的、在时间与情境中保持稳定的行为差异，例如“大胆性（boldness）”。已有研究表明，这类特质既具有遗传性，同时也会受到捕食压力等外部因素的影响。目前学界对于早期环境因素在动物个性形成中所发挥的作用仍知之甚少。因此，本研究以卵生爬行动物鬃狮蜥（Pogona vitticeps）为研究对象，探究孵化温度对其大胆性的影响。实验选取同一窝的卵，在正常孵化温度范围内的两种不同平均温度下进行孵化。幼体破壳后，所有蜥蜴均在相同的环境条件下饲养。本研究采用新物体识别实验与新环境实验对其个性进行评估，且分别在短期与长期两个时间维度下重复开展上述两项实验。结果显示，孵化温度确实会对“大胆性”产生影响，但该影响仅存在于短期维度。这表明，孵化温度并未直接作用于动物个性，而是可能在个体发育的不同阶段影响卵生爬行动物的行为发育。