School of Biological Sciences A08, University of Sydney, Sydney, New South Wales, Australia.
PLoS One. 2014 Jan 24;9(1):e86271. doi: 10.1371/journal.pone.0086271. eCollection 2014.
A species' intelligence may reliably predict its invasive potential. If this is true, then we might expect invasive species to be better at learning novel tasks than non-invasive congeners. To test this hypothesis, we exposed two sympatric species of Australian scincid lizards, Lampropholis delicata (invasive) and L. guichenoti (non-invasive) to standardized maze-learning tasks. Both species rapidly decreased the time they needed to find a food reward, but latencies were always higher for L. delicata than L. guichenoti. More detailed analysis showed that neither species actually learned the position of the food reward; they were as likely to turn the wrong way at the end of the study as at the beginning. Instead, their times decreased because they spent less time immobile in later trials; and L. guichenoti arrived at the reward sooner because they exhibited "freezing" (immobility) less than L. delicata. Hence, our data confirm that the species differ in their performance in this standardized test, but neither the decreasing time to find the reward, nor the interspecific disparity in those times, are reflective of cognitive abilities. Behavioural differences may well explain why one species is invasive and one is not, but those differences do not necessarily involve cognitive ability.
一个物种的智力可以可靠地预测其入侵潜力。如果这是真的，那么我们可能期望入侵物种比非入侵同属种更擅长学习新任务。为了验证这一假设，我们让两种澳大利亚石龙子蜥蜴——细鳞蜥（入侵种）和吉氏石龙子（非入侵种）——接受标准化的迷宫学习任务。这两个物种都能迅速减少找到食物奖励所需的时间，但细鳞蜥的潜伏期总是比吉氏石龙子高。更详细的分析表明，这两个物种实际上都没有学会食物奖励的位置；在研究结束时，它们走错方向的可能性与开始时一样大。相反，它们的时间减少是因为它们在后续试验中静止不动的时间减少了；而吉氏石龙子比细鳞蜥更快地到达了奖励地点，因为它们表现出的“冻结”（不动）比细鳞蜥少。因此，我们的数据证实，这两个物种在这个标准化测试中的表现存在差异，但无论是找到奖励所需的时间减少，还是两个物种之间时间的差异，都不能反映认知能力。行为差异很可能解释了为什么一个物种具有入侵性，而另一个物种没有，但这些差异不一定涉及认知能力。
