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.

棕榈果是全球陆生动物的重要食物资源，在热带区域尤为突出。皇后椰（Syagrus romanzoffiana）的种子，是松鼠Guerlinguetus ingrami关键的营养来源。该松鼠既是这类重要棕榈的种子捕食者，也是果实食性动物群落中的种子传播者，但目前学界尚未明确该松鼠如何选择并处理皇后椰的种子。本研究旨在探究三个核心问题：（1）验证该松鼠能否辨别果实的三个开孔中何者为萌发孔（germinal orifice），以实现更高效的果实破开操作；（2）评估果实内果皮（endocarp）的厚度与尺寸是否会影响该松鼠觅食时的选择偏好；（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倾向。为此，我们采用行为实验技术，控制预测变量并实时观测松鼠的行为变化。研究结果显示：（1）该松鼠通过对比开孔深度，识别出相对更深的萌发孔；（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。该松鼠演化出高效破开皇后椰果实的策略，表明该食物资源对其生存具有极高的重要性。此外，由于该松鼠偏好取食果实内的无脊椎动物寄生物，它能够抑制这类果实寄生虫的种群规模，从而为棕榈种群提供了关键的生态服务。