Foraging theory upscaled: the behavioural ecology of herbivore movement

We outline how principles of optimal foraging developed for diet and food patch selection might be applied to movement behaviour expressed over larger spatial and temporal scales. Our focus is on large mammalian herbivores, capable of carrying global positioning system (GPS) collars operating through the seasonal cycle and dependent on vegetation resources that are fixed in space but seasonally variable in availability and nutritional value. The concept of intermittent movement leads to the recognition of distinct movement modes over a hierarchy of spatio-temporal scales. Over larger scales, periods with relatively low displacement may indicate settlement within foraging areas, habitat units or seasonal ranges. Directed movements connect these patches or places used for other activities. Selection is expressed by switches in movement mode and the intensity of utilization by the settlement period relative to the area covered. The type of benefit obtained during settlement periods may be inferred from movement patterns, local environmental features, or the diel activity schedule. Rates of movement indicate changing costs in time and energy over the seasonal cycle, between years and among regions. GPS telemetry potentially enables large-scale movement responses to changing environmental conditions to be linked to population performance.     

同一山洞中五种蝙蝠的回声定位比较及生态位的分化

对同一山洞中5种蝙蝠的回声定位叫声和外部形态作了比较分析,根据蝙蝠回声定位叫声,形态特征与捕食策略之间的联系,并结合部分的野外观察研究,推断其捕食生境及捕食策略,并对洞中5种共栖蝙蝠的生态位分化进行了分析;研究结果如下：（1）南蝠（Ia io)在地面或树冠中间的开阔空间捕食个体较大的昆虫;（2）大鼠耳蝠（Myotis myotis)主要以掠食性方式（gleaning) 捕食森林或草地地表面的昆虫;（3）黄大蹄幅（Hipposideros pratti)主要在树冠周围或树冠上方进行捕蝇器式（Fly-catching)（即倒挂于一固定枝条或地点,探索周围飞行或接近的昆虫,探索到后捕捉回原倒挂地点再进食）或飞行捕食,它主要捕食个体较大的甲虫;（4）角菊头蝠（Rhinolophus cornutus)主要在较密集树木中（枝叶间）,农田及树木周围捕食型较小的翼拍动昆虫;（5）三叶蹄幅（Aselliscus wheeleri)是在树木,灌丛或在其周围空间内捕食较小的翼拍动昆虫,但其食性可能菊头蝠不同,根据以上研究结果,认为这5种蝙蝠的取食生态位存在着明显的分化。     

马铁菊头蝠对同种咀嚼声的反应研究

咀嚼是哺乳动物食物吸收的重要组成部分,对动物的生存和繁殖极其重要。动物咀嚼时会发出低频低强度的咀嚼声,研究表明人类的咀嚼声可以增强自身或他人的食欲和愉悦度。蝙蝠作为哺乳动物中的第二大类群,其咀嚼声的特征和功能仍不清楚。本研究以吉林省集安市治安村的马铁菊头蝠Rhinolophus ferrumequinum为研究对象,通过回放蝙蝠咀嚼声和空白对照实验,同步录制蝙蝠的进食行为和回声定位声波,试图阐明蝙蝠咀嚼声对其进食行为和回声定位声波的影响。结果表明:进食次数在2种回放条件下的差异无统计学意义,但捕食尝试在2种回放条件下的差异有统计学意义。因此,咀嚼声能够显著地提高蝙蝠的进食欲望。此外,在蝙蝠咀嚼声的刺激下,其回声定位声波的频率增加,持续时间延长,脉冲速率减慢。这可能是因为蝙蝠在咀嚼声的影响下改变发声动机,从而改变了其回声定位声波的频谱时间结构。本研究第一次报道了蝙蝠咀嚼声对其进食行为的影响,为进一步阐明蝙蝠咀嚼声的功能和进化具有重要意义。     

Some Recent Developments in Evolutionary Approaches to the Study of Human Cognition and Behavior

In this paper I review some theoretical exchanges and empiricalresults from recent work on human behavior and cognition in thehope of indicating some productive avenues for critical engagement.I focus particular attention on methodological debates between Evolutionary Psychologists and behavioral ecologists. I argue for a broader and more encompassing approach to the evolutionarily based study of human behavior and cognition than either of these two rivals present.     

Use of Social and Ecological Information in Tamarin Foraging Decisions

A major consequence of group living is that foragers may rely on social information in addition to ecological information to locate feeding sites. Although conspecifics can provide cues as to the spatial location of food patches, individual foraging decisions also must include some assessment of the likelihood of obtaining access to a resource other group members seek. This likelihood differs in the 2 models generally proposed to explain intragroup social foraging: the information-sharing model and the producer-scrounger model. We conducted an experimental field study on wild groups of emperor (Saguinus imperator) and saddleback (S. fuscicollis) tamarins to determine the foraging strategies adopted by individual group members and their relationship to social rank, food intake, and the ability to use ecological and social information in making intra-patch foraging decisions. Individual tamarins applied different behavioral strategies compatible with a finder-joiner paradigm to solve foraging problems. About half of the individuals in each study group initiated 74%–90% of all food searches and acted as finders. Most alpha individuals adopted a joiner strategy by monitoring the activities of others' to obtain a reward. The individual arriving first at a reward platform enjoyed a finder's advantage. Despite differences in search effort, both finders and joiners presented similar abilities in learning to associate ecological cues with the presence of food rewards at our experimental feeding stations. We conclude that within a group foraging context, tamarins integrate social and ecological information in decision-making.     

Foraging in tropical rain forests: The case of the penan of Sarawak,East Malaysia (Borneo)

Bailey et al. (1989) and Headland (1987) have recently proposed hypotheses stating that human foragers are unable to live in undisturbed tropical rain forests without some reliance on cultivated foods. The present discussion considers these hypotheses, as well as some of the evidence by which they have been tested. Four conceptual problems in the way these hypotheses have been formulated are identified: (1) assumptions about the relationship between key features of tropical forest ecosystems and human subsistence potential, (2) in-consistencies in the definition of pure foraging, (3) adherence to a dichotomy between foraging and agriculture, the result being that conscious and unconscious effects of exploitation on the demographic parameters of key resources is ignored, and (4) problems in defining the significance of ecotones. I consider the case of Penan hunter-gatherers of Borneo, a population which, by virtue of their reliance on the sago palm Eugeissona utilis, contradicts the conclusions of Bailey et al. and Headland. I consider salient aspects of Penan reliance on Eugeissona, and describe how Penan exploitation of this resource may positively effect its availability. This case is seen to provide a challenge to the hypotheses of Bailey et al. and Headland, not only in the extent to which it contradicts their conclusions but, more significantly, in what it reveals about the assumptions upon which their hypotheses are based. This points to the need for greater precision in the definition of future hypotheses about foraging in tropical forests.     

Human adaptation and energetic efficiency

A lack of consensus on the general adaptive significance of energetic efficiency can be shown to exist in ecology and anthropology. After briefly reviewing key studies in optimal foraging theory and ecological anthropology, a model is presented which includes the following elements: (1) an equation of adaptive success with reproductive fitness, within an optimality framework; (2) a definition of energy limitation consistent with this framework; (3) a distinction between efficiency of energy capture and efficiency of energy use in achieving other goals; (4) a multiple definition of energetic efficiency that distinguishes purely energetic measures (output/input) from rate measures (energy captured per unit time); (5) the inclusion of time budgeting as a primary adaptive constraint; (6) a quantitative demonstration that increased output/input ratios do not consistently predict an increase in net energy captured, and are poor measures where time is a constraint. The general conclusion is that where energy is limiting, increased efficiency in the rate of energy capture will be adaptive because more net energy will be made available; where energy is not limiting, an increased net capture rate may still confer increased adaptive success, since time and labor energy are freed from energy-capture activities and can be devoted to achieving other adaptive goals. But while energetic efficiency, properly defined, is shown to have general adaptive significance in all cases where time or energy are constraints, considerations of adaptive optimality preclude the general equation of energetic efficiency and adaptive success.     

What moves us? How mobility and movement are at the center of human evolution

Movement is central to the survival of all free‐living organisms. Consequently, movement and what anthropologists often refer to as mobility, which is the sum of small‐scale movements tracked across larger geographic and temporal scales, are key targets of selection. Movement and mobility also underpin many of the key features that make us human and that allowed our lineage to adapt to changing environments across the globe. The most obvious example is the evolution of humans' singular mode of locomotion. Bipedalism is arguably the most important derived anatomical trait of the hominin lineage. The mechanisms and circumstances that gave rise to this novel mode of movement remain subjects of intense research.     

The Importance of Behavioral Plasticity for Maximizing Foraging Efficiency in Frugivorous Lepidopteran Larvae

In this study, we present evidence that the larvae of Acrobasis vaccinii (Lepidoptera: Pyralidae), a species that feeds on cranberry fruit, are able to take into account at least three cues (fruit size, fruit color, and the distance between fruits) when searching for food. In laboratory experiments, the relative impact of each cue depended on which cues were presented in a given bioassay. Fruit color was the dominant cue in some contexts (e.g., larvae showed a significant perference for green fruit over red ones regardless of fruit size when fruits were equidistant from the larvae) but not in others (e.g., when given a choice between a large red fruit placed close to the larvae and a small green fruit placed farther away, a significantly higher proportion of larvae chose the former). This plasticity in foraging behavior allows larvae to maximize foraging efficiency under conditions of differing fruit and larval densities, which this species experiences in nature.     

四川绵阳洞栖蝙蝠多样性及受胁现状

1999～2005年,对四川省绵阳市洞栖性蝙蝠进行了凋杳。共采集到4科,5属,14种,约占四川蝙蝠种类31．8％,中国蝙蝠种类11．7％。其中,大足鼠耳蝠（Myotis ricketti）为中国特有种,中华鼠耳蝠（Myotis chinensis）已被列入《中国物种红色名录》中的易危（VU）种,南蝠（Iu io）等5种被列入近危（NT）种。调查中发现不少洞穴已被开发或正在被开发成旅游景点,人为干扰已严重威胁洞穴内蝙蝠的生存。建议对蝙蝠栖息地采取一定的保护措施,并加强保护蝙蝠的宣传教育。     

Causes,proximate and ultimate

Within evolutionary biology a distinction is frequently made between proximate and ultimate causes. One apparently plausible interpretation of this dichotomy is that proximate causes concern processes occurring during the life of an organism while ultimate causes refer to those processes (particularly natural selection) that shaped its genome. But ultimate causes are not sought through historical investigations of an organisms lineage. Rather, explanations referring to ultimate causes typically emerge from functional analyses. But these functional analyses do not identify causes of any kind, much less ultimate ones. So-called ultimate explanations are not about causes in any sense resembling those of proximate explanations. The attitude, implicit in the term ultimate cause, that these functional analyses are somehow superordinate to those involving proximate causes is unfounded. Ultimate causes are neither ultimate nor causes.