Transfer from continuous to discrete quantities in honeybees

Honeybees can estimate quantities having different dimensions: continuous and uncountable such as the relative size of visual objects in an array, or discrete and countable such as the number of objects of the array. Honeybees can transfer quantity discrimination (i.e., choosing the larger/smaller stimulus) from number to size. Here we investigated whether honeybees could also generalize from the size (continuous) to the number (discrete) dimension. We trained free-flying foragers to discriminate between large and small size elements. At test, bees were presented with a comparison between larger and smaller numerosities controlled for different continuous variables co-varying with numerosity such as total area, total perimeter, convex hull, and element size. Results showed that bees generalized from the size to the numerical dimension of the stimuli. This cross-dimensional transfer supports the idea of a universal mechanism for the encoding of abstract magnitudes in invertebrate species comparable to that of vertebrate species.

蜜蜂具备估算不同维度数量的能力：连续不可数维度，例如阵列中视觉对象的相对大小；离散可数维度，例如阵列中对象的数量。蜜蜂可将数量辨别能力（即选择更大或更小的刺激物）从数量维度迁移至大小维度。本研究旨在探究蜜蜂是否也能从大小（连续）维度泛化至数量（离散）维度。我们训练自由飞行的觅食蜂区分大小各异的视觉元素。测试阶段，我们向蜜蜂呈现数量多寡有别的两组刺激物，并控制了与数量共变的各类连续变量，包括总面积、总周长、凸包（convex hull）以及单个元素的大小。实验结果表明，蜜蜂能够将刺激物的大小维度泛化至数量维度。这种跨维度迁移现象，印证了无脊椎动物与脊椎动物类似，存在用于编码抽象数量的通用机制这一观点。