Repellent scent-marking of flowers by a guild of foraging bumblebees (Bombus spp.)

We have found that foraging bumblebees (Bombus hortorum, B. pascuorum, B. pratorum and B.␣terrestris) not only avoid flowers of Symphytum officinale that have recently been visited by conspecifics but also those that have been recently visited by heterospecifics. We propose that the decision whether to reject or accept a flower is influenced by a chemical odour that is left on the corolla by a forager, which temporarily repels subsequent foragers. Honeybees and carpenter bees have previously been shown to use similar repellent forage-marking scents. We found that flowers were repellent to other bumblebee foragers for approximately 20 min and also that after this time nectar levels in S. officinale flowers had largely replenished. Thus bumblebees could forage more efficiently by avoiding flowers with low rewards. Flowers to which extracts of tarsal components were applied were more often rejected by wild B. terrestris workers than flowers that had head extracts applied, which in turn were more often rejected than flowers that had body extracts applied. Extracts from four Bombus species were equally repellent to foragers. The sites of production of the repellent scent and its evolutionary origins are discussed. Received: 24 November 1997 / Accepted after revision: 8 March 1998     

Choosing rewarding flowers; perceptual limitations and innate preferences influence decision making in bumblebees and honeybees

Flowers exhibit great intra-specific variation in the rewards they offer. At any one time, a significant proportion of flowers often contain little or no reward. Hence, foraging profitably for floral rewards is problematic and any ability to discriminate between flowers and avoid those that are less rewarding will confer great advantages. In this study, we examine discrimination by foraging bees among flowers of nasturtium, Tropaeolum majus. Bee visitors included carpenter bees, Xylocopa violacea, which were primary nectar robbers; honeybees, Apis mellifera, which either acted as secondary nectar robbers or gathered pollen legitimately and bumblebees, Bombus hortorum, which were the only bees able to gather nectar legitimately. Many flowers were damaged by phytophagous insects. Nectar volume was markedly lower in flowers with damaged petals (which were also likely to be older) and in flowers that had nectar-robbing holes. We test whether bees exhibit selectivity with regards to the individual flowers, which they approach and enter, and whether this selectivity enhances foraging efficiency. The flowers approached (within 2 cm) by A. mellifera and B. hortorum were non-random when compared to the floral population; both species selectively approached un-blemished flowers. They both approached more yellow flowers than would be expected by chance, presumably a reflection of innate colour preferences, for nectar standing crop did not vary according to flower colour. Bees were also more likely to accept (land on) un-blemished flowers. A. mellifera gathering nectar exhibited selectivity with regards to the presence of robbing holes, being more likely to land on robbed flowers (they are not able to feed on un-robbed flowers). That they frequently approached un-robbed flowers suggests that they are not able to detect robbing holes at long-range, so that foraging efficiency may be limited by visual acuity. Nevertheless, by using a combination of long-range and short-range selectivity, nectar-gathering A. mellifera and B. hortorum greatly increased the average reward from the flowers on which they landed (by 68% and 48%, respectively) compared to the average standing crop in the flower population. Overall, our results demonstrate that bees use obvious floral cues (colour and petal blemishes) at long-range, but can switch to using more subtle cues (robbing holes) at close range. They also make many mistakes and some cues used do not correlate with floral rewards.     

The undermining effect revisited: The salience of everyday verbal rewards and self‐determined motivation

Self‐determination theory suggests that some rewards can undermine autonomous motivation and related positive outcomes. Key to this undermining is the extent to which rewards are perceived as salient in a given situation; when this is the case, individuals tend to attribute their behavior to the incentive, and the intrinsic value of the task is undermined. The role of salience has yet to be explicitly tested with respect to work motivation; we know little about whether undermining occurs in relation to verbal rewards, which characterize everyday work. We examine this in a field‐based quantitative diary study of 58 employees reporting 287 critical incidents of motivated behavior. When considering simple direct effects, the undermining effect was not supported; highly salient verbal rewards associated positively with introjected and external motivation, but at no cost to autonomous motivation. However, moderator analysis found support for the undermining effect for complex tasks; highly salient verbal rewards associated positively with external motivation while associating negatively with intrinsic and identified motivation. The findings suggest that verbal reward salience is an important characteristic of verbal reward perceptions and that salient verbal rewards are not advisable for more complex tasks but can have a valuable motivational impact for simple tasks. Copyright © 2015 John Wiley & Sons, Ltd.     

Rewards and employee creative performance: Moderating effects of creative self‐efficacy,reward importance,and locus of control

The effects of extrinsic rewards on creative performance have been controversial, and scholars have called for the examination of the boundary conditions of such effects. Drawing upon expectancy theory, we attend to both reinforcement and self‐determination pathways that reveal the informational and controlling functions of creativity‐related extrinsic rewards. We further identify the individual dispositions that moderate these two pathways. Specifically, we propose that extrinsic rewards for creativity positively predict creative performance only when employees have high creative self‐efficacy and regard such rewards as important. We likewise propose that extrinsic rewards positively affect the intrinsic motivation of employees with an internal locus of control, thus enhancing their creative performance. Results based on a sample of 181 employee–supervisor dyads largely supported these expectations. The current analysis enriches the creativity literature by combining different perspectives in a coherent framework, by demonstrating the positive effects of extrinsic rewards on intrinsic motivation, and by demonstrating that the rewards–creativity relationship varies across employees depending on their individual differences. Copyright © 2014 John Wiley & Sons, Ltd.     

Evaluation of pay-for-release conservation incentives for unintentionally caught threatened species

In the developing world, the exploitation of threatened species jeopardizes their permanence in the wild. Because not all captures are intentional, for instance when capture methods have low selectivity, pressure on these species may be lessened by releasing living incidentally caught animals. However, it is often unrealistic to expect people to voluntarily do so because it means foregoing the benefits of resource extraction. Financial incentives for such animal release may foster conservation objectives. Reducing human–animal conflicts, protecting natural habitat, and conserving nests of threatened species are examples of conservation benefits that can be built on financial reward systems. However, incentives aiming to protect unintentionally captured threatened species are scarce. We considered pay for release, a type of ecosystem-service payment designed to foster the release of incidentally captured threatened species. We aimed to determine the best conditions to implement this scheme, its potential benefits (e.g., incentivizing the release of threatened species), and pitfalls and priority research needs (e.g., required conditions for pay for release to work) to show that its global applicability is possible. Given that approaches solely based on education and law enforcement may be ineffective under some circumstances, we argue that pay for release can protect incidentally captured endangered species if used under conditions conducive for its success. When local participants’ intrinsic motivation for conservation is weak, but the release of incidentally live-caught animals into their habitats is readily achievable, pay-for-release schemes could jump start urgently needed conservation efforts against indiscriminate animal harvesting.     

谈新大学生军训中的思想和作风收获

本文立足军训大学生思想作风素质的提升,为进一步巩固校园来之不易的军训成果,结合大一新生的军训实际,从思想意识、意志力水平、作风纪律性、生活自立精神等六个方面概括了大学生在军训中的思想和作风收获.     

Leadership behaviors and follower performance: Deductive and inductive examination of theoretical rationales and underlying mechanisms

There are competing theoretical rationales and mechanisms used to explain the relation between leadership behaviors (e.g., consideration, initiating structure, contingent rewards, and transformational leadership) and follower performance (e.g., task performance and organizational citizenship behaviors). We conducted two studies to critically examine and clarify the leadership behaviors–follower performance relation by pitting the various theoretical rationales and mechanisms against each other. We first engaged in deductive (Study 1) and then inductive (Study 2) theorizing and relied upon 35 meta‐analyses involving 3327 primary‐level studies and 930 349 observations as input for meta‐analytic structural equation modeling. Results of our dual deductive–inductive approach revealed an unexpected yet surprisingly consistent explanation for why leadership behaviors affect follower performance. Specifically, leader–member exchange is a mediating mechanism that was empirically determined to be involved in the largest indirect relations between the four major leadership behaviors and follower performance. This result represents a departure from current conceptualizations and points to a common underlying mechanism that parsimoniously explains how leadership behaviors relate to follower performance. Also, results lead to a shift in terms of recommendations for what leaders should focus on to bring about improved follower performance. Copyright © 2016 John Wiley & Sons, Ltd.     

安全激励对具从众动机的建筑工人不安全行为的干预作用

为了研究安全激励对具有从众动机的建筑工人不安全行为的干预作用,识别建筑工人不安全行为的影响及干预因素,分别对具有从众动机的建筑工人不安全行为发生机理、安全奖励和安全惩罚的干预机理进行假定。基于调研数据,采用SPSS和AMOS工具展开模型拟合。研究结果表明:安全激励对建筑工人不安全行为有一定的干预作用;奖励对从众动机建筑工人的安全动机的端正产生0.108的正向影响、对安全能力的提升产生0.121的正向影响;惩罚对从众动机的建筑工人的安全心理健康产生0.140的正向影响、对安全知识的学习产生0.250的正向影响。基于此,提出预防具有从众动机的建筑工人不安全行为的有效措施。     

Relative Importance of Intrinsic,Extrinsic, and Anthropic Factors in the Geomorphic Zonation of the Trinity River,Texas1

Phillips, Jonathan D., 2010. Relative Importance of Intrinsic, Extrinsic, and Anthropic Factors in the Geomorphic Zonation of the Trinity River, Texas. Journal of the American Water Resources Association (JAWRA) 46(4): 807-823. DOI: 10.1111/j.1752-1688.2010.00457.x Abstract: The Trinity River, Texas, was characterized according to its geologic framework, valley width and confinement, slope, sinuosity, channel-floodplain connectivity, and flow regime, leading to the identification of 18 hinge points along the 638 km study area where major transitions in two or more criteria occur. These, and effects of human agency, avulsions, and sea level rise, delineate 21 river styles or zones. Each zone was evaluated with respect to dominant factors determining its geomorphological characteristics: geology/lithology, tectonics, Holocene sea level rise, meandering, cutoffs and other lateral channel changes, avulsions, valley constrictions by alluvial terraces, and paleomeander depressions. Direct human influences (a large impoundment and water withdrawals) are also evident. Entropy of the relationships between these controls and the geomorphological zones shows that all the controls are significant, and each accounts for 4-15% of the total entropy. Geologic controls, lateral channel changes, and constriction by terraces are the three most influential controls, illustrating that controls on river morphology include extrinsic boundary conditions, active process-form interrelationships, and inherited features. Extrinsic and intrinsic controls each account for about a third of the entropy, but the latter includes antecedent features as well as active channel dynamics, underscoring the importance of historical contingency even in alluvial rivers.