Abstract:
Recent evidence suggests that individuals differ in foraging tactics and this variation is often linked to an individual\'s behavioural type (BT). Yet, while foraging typically comprises a series of search and handling steps, empirical investigations have rarely considered BT-dependent effects across multiple stages of the foraging process, particularly in natural settings. In our long-term sleepy lizard (Tiliqua rugosa) study system, individuals exhibit behavioural consistency in boldness (measured as an individual\'s willingness to approach a novel food item in the presence of a threat) and aggressiveness (measured as an individual\'s response to an \'attack\' by a conspecific dummy). These BTs are only weakly correlated and have previously been shown to have interactive effects on lizard space use and movement, suggesting that they could also affect lizard foraging performance, particularly in their search behaviour for food. To investigate how lizards\' BTs affect their foraging process in the wild, we supplemented food in 123 patches across a 120-ha study site with three food abundance treatments (high, low and no-food controls). Patches were replenished twice a week over the species\' entire spring activity season and feeding behaviours were quantified with camera traps at these patches. We tracked lizards using GPS to determine their home range (HR) size and repeatedly assayed their aggressiveness and boldness in designated assays. We hypothesised that bolder lizards would be more efficient foragers while aggressive ones would be less attentive to the quality of foraging patches. We found an interactive BT effect on overall foraging performance. Individuals that were both bold and aggressive ate the highest number of food items from the foraging array. Further dissection of the foraging process showed that aggressive lizards in general ate the fewest food items in part because they visited foraging patches less regularly, and because they discriminated less between high and low-quality patches when revisiting them. Bolder lizards, in contrast, ate more tomatoes because they visited foraging patches more regularly, and ate a higher proportion of the available tomatoes at patches during visits. Our study demonstrates that BTs can interact to affect different search and handling components of the foraging process, leading to within-population variation in foraging success. Given that individual differences in foraging and movement will influence social and ecological interactions, our results highlight the potential role of BT\'s in shaping individual fitness strategies and population dynamics.
摘要:
最近的证据表明,个体在觅食策略上有所不同,这种变化通常与个体的行为类型(BT)有关。然而,觅食通常包括一系列搜索和处理步骤,实证研究很少考虑在觅食过程的多个阶段的BT依赖效应,特别是在自然环境中。在我们长期困倦的蜥蜴(Tiliquarugosa)研究系统中,个体表现出行为一致性的胆量(衡量为个体在存在威胁的情况下接近新食品的意愿)和攻击性(衡量为个体对特定假人的“攻击”的反应)。这些BT仅是弱相关的,并且先前已被证明对蜥蜴空间的使用和移动具有交互影响,表明它们也会影响蜥蜴的觅食性能,特别是在他们寻找食物的行为中。为了研究蜥蜴\'BT如何影响它们在野外的觅食过程,我们在120公顷的研究地点用三种食物丰富的治疗方法(高,低和无食物控制)。在整个春季活动季节,每周两次补充补丁,并在这些补丁上使用相机陷阱对喂养行为进行量化。我们使用GPS跟踪蜥蜴以确定它们的家庭范围(HR)大小,并在指定的测定中反复分析它们的侵略性和胆量。我们假设,大胆的蜥蜴将是更有效的觅食者,而侵略性的蜥蜴将不那么关注觅食斑块的质量。我们发现BT对整体觅食性能有相互作用的影响。既大胆又有侵略性的人从觅食阵列中摄取了最多的食物。对觅食过程的进一步解剖表明,进攻性蜥蜴通常吃最少的食物,部分原因是它们不太经常访问觅食斑块,因为他们在重新审视高质量和低质量的补丁时,对它们的区分较少。更大胆的蜥蜴,相比之下,吃了更多的西红柿,因为他们更经常地访问觅食斑块,并在访问期间在补丁中吃了更高比例的可用西红柿。我们的研究表明,BT可以相互作用以影响觅食过程的不同搜索和处理组件,导致觅食成功的种群内部差异。鉴于觅食和运动的个体差异将影响社会和生态互动,我们的结果强调了BT在塑造个体健身策略和种群动态方面的潜在作用.