Data from: Queen palm fruit selection and foraging techniques by squirrels in the Atlantic Forest

Palm fruits are a significant resource for fauna worldwide, particularly in tropical regions. Such is the case for queen palm seeds (Syagrus romanzoffiana), which is a vital source of nutrients for the squirrel Guerlinguetus ingrami. This squirrel acts as seed predator, as well as seed disperser of this important palm for the frugivore community, but we don´t know how this squirrel select and manipulate the queen palm seeds. The objective of this study was to address three key topics: (1) investigate the squirrel’s capacity to discern which of the fruit’s three pores is the germinal orifice, which permits a more efficient opening of the fruit; (2) assess whether the thickness and size of the fruit endocarp influence the squirrel’s selection during foraging; and (3) evaluate the intentionality of the rodents to prey on the invertebrates within the fruit. For this, we used behavioral experimentation techniques, controlling the predictor variables and observing the changes in the squirrel’s behavior. We found that (1) the squirrel identified the germinal pore by its greater depth relative to the other pores; (2) the size and thickness of the fruit not influences the squirrel’s choice; and (3) the squirrel prefers to consume fruits infested by invertebrates. The development of strategies to more efficiently open the queen palm fruit indicates the importance of this resource to the squirrels. In addition, due to the preference for invertebrates, the squirrel controls the population of these fruit parasites, providing a service to the population of palm trees.棕榈果实是全球各类动物的重要食物资源，在热带区域尤为关键。以皇后葵（Syagrus romanzoffiana）的种子为例，其为英格拉姆松鼠（Guerlinguetus ingrami）提供了关键的营养来源。该松鼠既是这类重要棕榈的种子捕食者，同时也是其种子传播者，为果食动物群落提供生态支撑，但目前学界尚不清楚该松鼠如何选择并处理皇后葵种子。本研究旨在解决三个核心科学问题：(1) 探究该松鼠能否辨别果实的三个微孔中哪个是萌发孔（germinal orifice）——该结构可使果实更高效地被打开；(2) 评估果实内果皮（endocarp）的厚度与尺寸是否会影响该松鼠在觅食过程中的选择偏好；(3) 探究该啮齿动物是否存在主动取食果实内无脊椎动物的行为意向。为此，我们采用行为实验技术，通过控制预测变量并实时观察松鼠的行为变化开展研究。研究结果显示：(1) 该松鼠通过对比微孔深度，识别出相较于其余微孔更深的萌发孔；(2) 果实的尺寸与内果皮厚度并不会影响该松鼠的选择；(3) 该松鼠更偏好取食被无脊椎动物侵染的果实。该松鼠演化出高效打开皇后葵果实的策略，这一现象印证了该食物资源对其生存的重要性。此外，由于该松鼠偏好取食无脊椎动物，其可抑制这类果实寄生虫的种群数量，从而为棕榈种群提供了重要的生态服务。