The ability to rapidly adjust thermal tolerance in response to variable temperatures may facilitate the success of invasive species in non-native ranges. The Asian house gecko Hemidactylus frenatus is native to the tropics of South and Southeast Asia. This small lizard has spread across the globe and has also successfully invaded colder regions of Australia. In this study, we investigated whether this species displays plasticity in thermal tolerance in its introduced range. We measured cold tolerance (CT_min) and heat tolerance (CT_max) of H. frenatus from two native tropical populations in Thailand, and two introduced subtropical populations in southeastern Australia. We also explored seasonal variation in the thermal tolerance of the introduced populations. We found that heat tolerance (CT_max) of geckos did not differ among four populations in Thailand and Australia (range = 43.4–43.7 °C). By contrast, geckos from southeastern Australia had lower cold tolerance (CT_min) (mean = 10.43 °C) than geckos from Thailand (mean = 11.57 °C). We also documented seasonal shifts in cold tolerance of H. frenatus from southeastern Australia. Geckos captured in winter had cold tolerances 1–2 °C lower than those captured in summer. Unexpectedly, this shift in cold tolerance was accompanied by a 1–2 °C upward shift in heat tolerance. Our results support a growing body of evidence showing that tropical invaders can adjust cold tolerance downwards via plasticity or acclimation. Such changes may allow tropical invaders to expand their geographic range into colder regions of non-native ranges.

响应温度变化而快速调节热耐受性的能力可以促进非本地范围内入侵物种的成功。亚洲壁虎Hemidactylus frenatus是原产于南亚和东南亚的热带地区。这种小蜥蜴已经遍布全球，并成功地入侵了澳大利亚的寒冷地区。在这项研究中，我们调查了该物种在引入范围内的热耐受性是否显示可塑性。我们测量了H. frenatus的耐寒性（CT _min）和耐热性（CT _max）来自泰国的两个热带原始种群，以及澳大利亚东南部的两个亚热带种群。我们还探讨了引入种群的热耐受性的季节性变化。我们发现，在泰国和澳大利亚的四个种群（范围= 43.4–43.7°C）中，壁虎的耐热性（CT _max）没有差异。相比之下，澳大利亚东南部的壁虎的耐寒性（CT _min）（平均= 10.43°C）低于泰国的壁虎（平均= 11.57°C）。我们还记录了H. frenatus的耐寒性的季节性变化来自澳大利亚东南部。冬季捕获的壁虎的耐寒性比夏季捕获的壁虎低1-2°C。出乎意料的是，这种耐寒性的变化伴随着耐热性上升1-2°C。我们的结果支持越来越多的证据表明，热带入侵者可以通过可塑性或适应性向下调节耐寒性。这种变化可能使热带入侵者将其地理范围扩展到非本地范围的较冷地区。