Dolev Yinnon, Nelson Ximena J
School of Biological Sciences, University of Canterbury, Christchurch, New Zealand.
PLoS One. 2014 Jun 3;9(6):e97819. doi: 10.1371/journal.pone.0097819. eCollection 2014.
The East African jumping spider Evarcha culicivora feeds indirectly on vertebrate blood by preferentially preying upon blood-fed Anopheles mosquitoes, the vectors of human malaria1, using the distinct resting posture and engorged abdomen characteristic of these specific prey as key elements for their recognition. To understand perceptual categorization of objects by these spiders, we investigated their predatory behavior toward different digital stimuli--abstract 'stick figure' representations of Anopheles constructed solely by known key identification elements, disarranged versions of these, as well as non-prey items and detailed images of alternative prey. We hypothesized that the abstract images representing Anopheles would be perceived as potential prey, and would be preferred to those of non-preferred prey. Spiders perceived the abstract stick figures of Anopheles specifically as their preferred prey, attacking them significantly more often than non-preferred prey, even when the comprising elements of the Anopheles stick figures were disarranged and disconnected from each other. However, if the relative angles between the elements of the disconnected stick figures of Anopheles were altered, the otherwise identical set of elements was no longer perceived as prey. These data show that E. culicivora is capable of making discriminations based on abstract concepts, such as the hypothetical angle formed by discontinuous elements. It is this inter-element angle rather than resting posture that is important for correct identification of Anopheles. Our results provide a glimpse of the underlying processes of object recognition in animals with minute brains, and suggest that these spiders use a local processing approach for object recognition, rather than a holistic or global approach. This study provides an excellent basis for a comparative analysis on feature extraction and detection by animals as diverse as bees and mammals.
东非跳蛛Evarcha culicivora通过优先捕食吸食过血液的按蚊间接摄取脊椎动物的血液，按蚊是人类疟疾的传播媒介。该跳蛛利用这些特定猎物独特的静止姿势和饱满的腹部特征作为识别它们的关键要素。为了了解这些蜘蛛对物体的感知分类，我们研究了它们对不同数字刺激的捕食行为——这些数字刺激是仅由已知关键识别要素构建的按蚊抽象“简笔画”表示、这些简笔画的打乱版本，以及非猎物项目和替代猎物的详细图像。我们假设，代表按蚊的抽象图像会被视为潜在猎物，并且会比非偏好猎物的图像更受青睐。蜘蛛将按蚊的抽象简笔画明确视为它们的偏好猎物，攻击这些简笔画的频率明显高于非偏好猎物，即使按蚊简笔画的组成要素被打乱且彼此不相连。然而，如果按蚊不相连简笔画要素之间的相对角度发生改变，那么原本相同的一组要素就不再被视为猎物。这些数据表明，E. culicivora能够基于抽象概念进行区分，比如由不连续要素形成的假设角度。对于正确识别按蚊而言，重要的是这种要素间的角度而非静止姿势。我们的研究结果让我们得以一窥具有微小大脑的动物进行物体识别的潜在过程，并表明这些蜘蛛使用局部处理方法进行物体识别，而非整体或全局方法。这项研究为对蜜蜂和哺乳动物等多种动物的特征提取和检测进行比较分析提供了绝佳的基础。
