نتایج جستجو برای: bromus secalinus l

تعداد نتایج: 619117  

Journal: :Annals of botany 2006
Xue-Hua Ye Fei-Hai Yu Ming Dong

BACKGROUND AND AIMS A phalanx growth form enables clonal plants to make better use of resource-rich patches, whereas a guerrilla growth form provides them with opportunities to escape from resource-poor sites. Leymus secalinus produces both spreading (guerrilla form) and clumping ramets (phalanx form). Here, the hypothesis that a trade-off between the two growth forms in L. secalinus exists und...

2002
Rob Hart Uwe Latacz-Lohmann

We introduce uncertainty about farmer characteristics into the moral hazard problem facing a regulator offering agri-environmental contracts. Our model allows for a continuum of farmer compliance costs. For reasonable parameter values the model predicts high levels of cheating and intensive monitoring, contrary to the evidence. We therefore add variation in farmers’ propensity to cheat, the reg...

Journal: :Journal of evolutionary biology 2010
R Kümmerli P van den Berg A S Griffin S A West A Gardner

Repression of competition (RC) within social groups has been suggested as a key mechanism driving the evolution of cooperation, because it aligns the individual's proximate interest with the interest of the group. Despite its enormous potential for explaining cooperation across all levels of biological organization, ranging from fair meiosis, to policing in insect societies, to sanctions in mut...

Journal: :Proceedings. Biological sciences 2010
Suzanne C Mills Isabelle M Côté

Cheating is common in cooperative interactions, but its occurrence can be controlled by various means ranging from rewarding cooperators to active punishment of cheaters. Punishment occurs in the mutualism involving the cleanerfish Labroides dimidiatus and its reef fish clients. When L. dimidiatus cheats, by taking scales and mucus rather than ectoparasites, wronged clients either chase or with...

Journal: :Current Biology 2005
Freya Harrison Angus Buckling

When the supply of beneficial mutations limits adaptation, bacterial mutator alleles can reach high frequencies by hitchhiking with advantageous mutations. However, when populations are well adapted to their environments, the increased rate of deleterious mutations makes hypermutability selectively disadvantageous. Here, we consider a further cost of hypermutability: its potential to break down...

2012
Andrew D Morgan Benjamin J Z Quigley Sam P Brown Angus Buckling

While the conditions that favour the maintenance of cooperation have been extensively investigated, the significance of non-social selection pressures on social behaviours has received little attention. In the absence of non-social selection pressures, patches of cooperators are vulnerable to invasion by cheats. However, we show both theoretically, and experimentally with the bacterium Pseudomo...

2016
S. Nageeb Ali David A. Miller David Yilin Yang

In multilateral enforcement, a player who cheats on one partner is punished by many partners. But renegotiation might subvert the threat of multilateral punishment. We consider renegotiation proofness in multilateral enforcement games with public monitoring, and also introduce the notion of “bilateral renegotiation proofness” for games with private monitoring. With public monitoring, renegotiat...

2017
Siobhán O'Brien Adela M Luján Steve Paterson Michael A Cant Angus Buckling

Cooperation in nature is ubiquitous, but is susceptible to social cheats who pay little or no cost of cooperation yet reap the benefits. The effect such cheats have on reducing population productivity suggests that there is selection for cooperators to mitigate the adverse effects of cheats. While mechanisms have been elucidated for scenarios involving a direct association between producer and ...

Journal: :Current Biology 2009
Kendra P. Rumbaugh Stephen P. Diggle Chase M. Watters Adin Ross-Gillespie Ashleigh S. Griffin Stuart A. West

The ability of pathogenic bacteria to exploit their hosts depends upon various virulence factors, released in response to the concentration of small autoinducer molecules that are also released by the bacteria [1-5]. In vitro experiments suggest that autoinducer molecules are signals used to coordinate cooperative behaviors and that this process of quorum sensing (QS) can be exploited by indivi...

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