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51.
Independence, not conflict, characterizes dart-shooting and sperm exchange in a hermaphroditic snail
Although the sexes are united in hermaphrodites, conflict can still occur because the male and female functions have separate
interests. We examined the evidence for conflict in the mating system of the terrestrial snail Cantareus aspersus (formerly Helix aspersa) where sharp, calcareous darts are ‘shot’ during courtship. We predicted that the use of the dart would either reflect or
create conflict and this would be evident in either the courtship behavior or the transference of sperm. Previous studies
demonstrated that the dart functions after sperm transfer to increase sperm survival. Using detailed observations of mating
snails, we examined the factors that determine dart shooting order, the behavioral responses after being hit by a dart, the
accuracy of dart shooting, and the allocation of sperm resources. We found that each dart was shot independently, and each
animal appeared to be interested only in getting off the best possible shot, probably one that penetrates deeply near the
genital pore. There is no evidence of mating conflict. Every snail transfers sperm to its partner, and the size of the donation
does not depend on the success or failure of either snail’s dart shot. Although the receipt of a dart does not appear to cause
harm, it may produce indirect costs due to the partial loss of control over fertilization. We conclude that mating in C. aspersus is a partnership in which independent actors demonstrate unconditional reciprocity during courtship and sperm transfer. 相似文献
52.
Joris M. Koene Tina Pförtner Nico K. Michiels 《Behavioral ecology and sociobiology》2005,59(2):243-249
Sexual conflict between mating partners can give rise to strategies that are advantageous for one sex but harmful to the opposite sex. Usually, sperm donors develop (offensive) traits to enhance their chances in sperm competition, while sperm recipients evolve (defensive) traits that allow them to stay in control of who fathers their offspring. Here, we demonstrate that these processes are also at work in simultaneous hermaphrodites. The hermaphroditic earthworm Lumbricus terrestris uses 40 to 44 copulatory setae to pierce into its partner's skin, causing damage and injecting a substance from its setal glands. Experimental injection of the gland substance indicates that a refractory period may be induced. More importantly, removal of the copulatory setae shows that they influence the partner's sperm uptake. When the setae are present, more sperm are taken up and sperm are distributed more equally over the four spermathecae. We interpret this as a strategy that stacks the odds for the donor's sperm in fertilizing cocoons. 相似文献
53.
Nathalie Stroeymeyt Elisabeth Brunner Jürgen Heinze 《Behavioral ecology and sociobiology》2007,61(9):1449-1457
Animal societies, including those of humans, are under constant threat by selfish individuals, who attempt to enforce their
own interests at the cost of the group. In the societies of bees, wasps, and ants, such individual selfishness can be prevented
by “policing,” whereby workers or queens impede the reproduction of other individuals by aggression, immobilization, or egg
eating. In this study, we report on a particular kind of reproduction control in the ant Temnothorax unifasciatus, which can be considered as a selfish act itself. We experimentally induced workers to lay eggs by dividing several colonies
into two halves, one with and one without a queen. In queenless colonies, workers established rank orders by aggression and
several top-ranking workers started to reproduce. Upon reunification, egg-laying workers mostly stopped behaving aggressively.
They were neither attacked by the queen nor by random workers, but instead received infrequent, nondestructive, targeted aggression
from a few workers, most of which became fertile when the queen was later removed. The introduction of differentially stained
worker-laid and queen-laid eggs in queenright fragments did not lead to a selective removal of worker-laid eggs. Hence, there
appears to be no collective worker policing in T. unifasciatus. Instead, reproduction appears to be controlled mostly through a few attacks from high-ranking workers, which, in this way,
might attempt to selfishly increase their chances of future reproduction. 相似文献
54.
Unkasević M Vukmirović Z Tosić I Lazić L 《Environmental science and pollution research international》2003,10(2):89-97
This study has shown theoretical, observed and experimental evidence of pollutants released, transported and deposited during the Kosovo conflict in 1999 and their effects on precipitation in Serbia. The greatest bombardment of the chemical industry, oil refineries and fuel storage in Serbia which occurred during April, resulted in releases of many hazardous, toxic and cancerogenic substances. The number of April's days with precipitation greater or equal to 0.1 mm in 1999 are compared to those in the period from 1961 to 1990 registered at thirty meteorological stations in Serbia and especially at the Belgrade-Observatory station in the period from 1888 to 1995. The maximums of days with precipitation greater or equal to 0.1 mm were at the wider Belgrade area and at the central and southwestern parts of Serbia during April 1999. This is confirmed by using the Eta trajectory analysis. 相似文献
55.
56.
为定量评价大坝浇筑过程空间冲突致灾事故后果,通过对缆机运输典型情景进行危害能量运动分解,确定在水平和竖直方向运动方式,阐述危害能量在流动路径相互转化形式;根据能量守恒定律,分析危害能量在吊罐与承灾体碰撞接触之间转移规律,将吊罐与人头部接触过程抽象为带强阻尼的弹簧振子系统,建立危害能量与碰撞冲量相等的动量方程,量化空间冲突致灾后果。结果表明:吊罐坠落危害能量极大,产生的碰撞冲击力与吊罐的运输速度、高度呈正相关,与阻力系数呈负相关,风速、载重对其影响较大。对比2种不同碰撞情景发现,机械碰撞因顶部承载力缓冲,对人头部产生伤害远小于直接碰撞,并对碰撞结果分级评价,研究结果可为大坝浇筑交叉作业空间冲突致灾风险评价提供参考。 相似文献
57.
Wildlife-road conflict has profound negative impacts on both wildlife populations and society. Despite a long-held understanding of this problem, in most regions the wildlife-management strategies (WMS) available to mitigate this conflict are still relatively underutilized. This study examines the implementation of these strategies into road infrastructure, using Southern Ontario as a case study, in order to develop an understanding of what leads to successful WMS implementation. The project management concept of critical success factors was applied and interviews with project decision-makers and key stakeholders were conducted. Nine factors were identified and a comparison between a ‘smooth’ and ‘rough’ project is used to illustrate the cumulative effects that these factors, and their interrelationships, have on project implementation success. Practitioners can use these findings to evaluate WMS projects based on likelihood of success and allocate resources accordingly, ultimately leading to increased chances of implementation and overall benefit to conservation and society. 相似文献
58.
Energy's role in the extraversion (dis)advantage: How energy ties and task conflict help clarify the relationship between extraversion and proactive performance
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While academic and practitioner literatures have proposed that extraverts are at an advantage in team‐based work, it remains unclear exactly what that advantage might be, how extraverts attain such an advantage, and under which conditions. Theory highlighting the importance of energy in the coordination of team efforts helps to answer these questions. We propose that extraverted individuals are able to develop more energizing relationships with their teammates and as a result are seen as proactively contributing to their team. However, problems in coordination (i.e., team task conflict) can reverse this extraversion advantage. We studied 27 project‐based teams at their formation, peak performance, and after disbandment. Results suggest that when team task conflict is low, extraverts energize their teammates and are viewed by others as proactively contributing to the team. However, when team task conflict is high, extraverts develop energizing relationships with fewer of their teammates and are not viewed as proactively contributing to the team. Our findings regarding energizing relationships and team task conflict clarify why extraversion is related to proactive performance and in what way, how, and when extraverts may be at a (dis)advantage in team‐based work. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
59.
The aim of this article is to conceptually delineate moral anger from other related constructs. Drawing upon social functional accounts of anger, we contend that distilling the finer nuances of morally motivated anger and its expression can increase the precision with which we examine prosocial forms of anger (e.g., redressing injustice), in general, and moral anger, in particular. Without this differentiation, we assert that (i) moral anger remains theoretically elusive, (ii) that this thwarts our ability to methodologically capture the unique variance moral anger can explain in important work outcomes, and that (iii) this can promote ill‐informed organizational policies and practice. We offer a four‐factor definition of moral anger and demonstrate the utility of this characterization as a distinct construct with application for workplace phenomena such as, but not limited to, whistle‐blowing. Next, we outline a future research agenda, including how to operationalize the construct and address issues of construct, discriminant, and convergent validity. Finally, we argue for greater appreciation of anger's prosocial functions and concomitant understanding that many anger displays can be justified and lack harmful intent. If allowed and addressed with interest and concern, these emotional displays can lead to improved organizational practice. © 2015 The Authors Journal of Organizational Behavior Published by John Wiley & Sons Ltd. 相似文献
60.
冲突分析理论方法及其在环境管理中的实例研究 总被引:6,自引:0,他引:6
对冲突分析的基本概念和原理做了简要介绍,以环境规划管理的的业务为背景,指出冲突问题的广泛存在和研究冲突分析的必要性,并就"污染集中治理的投资分摊问题"进行深入地探讨,提出了5种协商解,通过分析比较,推荐"不次于N-1方合作收益的协商解"作为一般问题的解,对于同情弱势方的仲裁者,则推荐"以不合作为现状点的基于满意度的协商解"。 相似文献