Experimental evidence that partner choice is a driving force in the payoff distribution among cooperators or mutualists: the cleaner fish case

Abstract Market-like situations emerge in nature when trading partners exchange goods and services. However, how partner choice option contributes to the expression of social strategic sophistication (i.e., the ability to adjust behavior flexibly given the specifics of a situation) is still poorly understood. A suitable study system to explore this question is the “cleaner” fish Labroides dimidiatus. Cleaners trade parasite removal in exchange for food with a variety of “client” species. Previous research documented strong interindividual variation in two features of their strategic sophistication, namely, the ability to adjust service quality to the presence of an audience and to give priority to clients with access to alternative cleaners (“visitor clients”) over clients lacking such choice options (“resident clients”). Here, we sampled various demes (i.e., group of individuals) of the same population of cleaner fish in order to investigate the extent to which factors describing fish densities and cleaning interaction patterns predict the strategic sophistication in two laboratory experiments. These experiments tested whether cleaners could increase their food intake through reputation management and/or learning to provide service priority to a visitor-like ephemeral food plate. We found that high “outbidding competition,” characterized by high densities of cleaners and visitor clients, along with visitor’s behavior promoting such competition, consistently predicted high strategic sophistication in cleaners. A better understanding of the role of learning versus potential genetic factors, interacting with local market conditions to affect strategic sophistication, is needed to clarify how natural selection has promoted the evolution and maintenance of cooperation in this cleaning mutualism.

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Key experimental evidence of chromosomal DNA transfer among selected tuberculosis-causing mycobacteria

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1604921113 ◽

2016 ◽

Vol 113 (35) ◽

pp. 9876-9881 ◽

Cited By ~ 56

Author(s):

Eva C. Boritsch ◽

Varun Khanna ◽

Alexandre Pawlik ◽

Nadine Honoré ◽

Victor H. Navas ◽

...

Keyword(s):

Experimental Evidence ◽

Driving Force ◽

Risk Evaluation ◽

Size Range ◽

Dna Transfer ◽

Whole Genome ◽

Proof Of Concept ◽

Chromosomal Dna ◽

Transfer Frequency ◽

The Impact

Horizontal gene transfer (HGT) is a major driving force of bacterial diversification and evolution. For tuberculosis-causing mycobacteria, the impact of HGT in the emergence and distribution of dominant lineages remains a matter of debate. Here, by using fluorescence-assisted mating assays and whole genome sequencing, we present unique experimental evidence of chromosomal DNA transfer between tubercle bacilli of the early-branching Mycobacterium canettii clade. We found that the obtained recombinants had received multiple donor-derived DNA fragments in the size range of 100 bp to 118 kbp, fragments large enough to contain whole operons. Although the transfer frequency between M. canettii strains was low and no transfer could be observed among classical Mycobacterium tuberculosis complex (MTBC) strains, our study provides the proof of concept for genetic exchange in tubercle bacilli. This outstanding, now experimentally validated phenomenon presumably played a key role in the early evolution of the MTBC toward pathogenicity. Moreover, our findings also provide important information for the risk evaluation of potential transfer of drug resistance and fitness mutations among clinically relevant mycobacterial strains.

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No experimental evidence for local competition in the nestling phase as a driving force for density-dependent avian clutch size

Journal of Animal Ecology ◽

10.1111/j.1365-2656.2009.01535.x ◽

2009 ◽

Vol 78 (4) ◽

pp. 828-838 ◽

Cited By ~ 10

Author(s):

Marion Nicolaus ◽

Christiaan Both ◽

Richard Ubels ◽

Pim Edelaar ◽

Joost M. Tinbergen

Keyword(s):

Experimental Evidence ◽

Clutch Size ◽

Driving Force ◽

Local Competition ◽

Density Dependent

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How do memory modules differentially contribute to familiarity and recollection?

Behavioral and Brain Sciences ◽

10.1017/s0140525x19001833 ◽

2019 ◽

Vol 42 ◽

Author(s):

Olya Hakobyan ◽

Sen Cheng

Keyword(s):

Recognition Memory ◽

Experimental Evidence ◽

Subjective Experience ◽

Target Article ◽

Memory Modules ◽

Familiarity And Recollection ◽

Memory Contents

Abstract We fully support dissociating the subjective experience from the memory contents in recognition memory, as Bastin et al. posit in the target article. However, having two generic memory modules with qualitatively different functions is not mandatory and is in fact inconsistent with experimental evidence. We propose that quantitative differences in the properties of the memory modules can account for the apparent dissociation of recollection and familiarity along anatomical lines.

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Redox Reactions in Lipid Membranes as a Model for Primordial Energy-Conserving Systems

International Astronomical Union Colloquium ◽

10.1017/s0252921100014950 ◽

1997 ◽

Vol 161 ◽

pp. 437-442

Author(s):

Salvatore Di Bernardo ◽

Romana Fato ◽

Giorgio Lenaz

Keyword(s):

Experimental Evidence ◽

Lipid Membranes ◽

Energy Supply ◽

Redox Reactions ◽

Living Systems ◽

Asymmetric Distribution ◽

Conservation Of Energy ◽

Asymmetrical Distribution ◽

Energy Conserving ◽

Living Organisms

AbstractOne of the peculiar aspects of living systems is the production and conservation of energy. This aspect is provided by specialized organelles, such as the mitochondria and chloroplasts, in developed living organisms. In primordial systems lacking specialized enzymatic complexes the energy supply was probably bound to the generation and maintenance of an asymmetric distribution of charged molecules in compartmentalized systems. On the basis of experimental evidence, we suggest that lipophilic quinones were involved in the generation of this asymmetrical distribution of charges through vectorial redox reactions across lipid membranes.

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A Method for Setting the Clearance Angle

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100095200 ◽

1972 ◽

Vol 30 ◽

pp. 388-389

Author(s):

Michael T. Bucek ◽

Howard J. Arnott

Keyword(s):

Experimental Evidence ◽

Light Source ◽

Black Spot ◽

Critical Factor ◽

Clearance Angle ◽

Crude Approximation ◽

Ultrathin Sections

It is believed by the authors, with supporting experimental evidence, that as little as 0.5°, or less, knife clearance angle may be a critical factor in obtaining optimum quality ultrathin sections. The degree increments located on the knife holder provides the investigator with only a crude approximation of the angle at which the holder is set. With the increments displayed on the holder one cannot set the clearance angle precisely and reproducibly. The ability to routinely set this angle precisely and without difficulty would obviously be of great assistance to the operator. A device has been contrived to aid the investigator in precisely setting the clearance angle. This device is relatively simple and is easily constructed. It consists of a light source and an optically flat, front surfaced mirror with a minute black spot in the center. The mirror is affixed to the knife by placing it permanently on top of the knife holder.

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In situ TEM Studies of agglomeration of sub-nanometer Ru layers in Ru/C multilayers

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100121685 ◽

1992 ◽

Vol 50 (1) ◽

pp. 256-257

Author(s):

Tai D. Nguyen ◽

Ronald Gronsky ◽

Jeffrey B. Kortright

Keyword(s):

Layered Structure ◽

Driving Force ◽

High Energy ◽

Superior Performance ◽

In Situ Tem ◽

Rayleigh Instability ◽

Practical Applications ◽

Transmission Electron ◽

Diffraction Patterns

Nanometer period Ru/C multilayers are one of the prime candidates for normal incident reflecting mirrors at wavelengths < 10 nm. Superior performance, which requires uniform layers and smooth interfaces, and high stability of the layered structure under thermal loadings are some of the demands in practical applications. Previous studies however show that the Ru layers in the 2 nm period Ru/C multilayer agglomerate upon moderate annealing, and the layered structure is no longer retained. This agglomeration and crystallization of the Ru layers upon annealing to form almost spherical crystallites is a result of the reduction of surface or interfacial energy from die amorphous high energy non-equilibrium state of the as-prepared sample dirough diffusive arrangements of the atoms. Proposed models for mechanism of thin film agglomeration include one analogous to Rayleigh instability, and grain boundary grooving in polycrystalline films. These models however are not necessarily appropriate to explain for the agglomeration in the sub-nanometer amorphous Ru layers in Ru/C multilayers. The Ru-C phase diagram shows a wide miscible gap, which indicates the preference of phase separation between these two materials and provides an additional driving force for agglomeration. In this paper, we study the evolution of the microstructures and layered structure via in-situ Transmission Electron Microscopy (TEM), and attempt to determine the order of occurence of agglomeration and crystallization in the Ru layers by observing the diffraction patterns.

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The nucleation of cavities at grain boundaries

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100126299 ◽

1987 ◽

Vol 45 ◽

pp. 288-291

Author(s):

P. J. Goodhew

Keyword(s):

Surface Tension ◽

Surface Energy ◽

Grain Boundaries ◽

Radiation Damage ◽

Impurity Concentration ◽

Driving Force ◽

Nucleation And Growth ◽

Phase Boundaries ◽

Cavity Nucleation ◽

Spherical Bubble

Cavity nucleation and growth at grain and phase boundaries is of concern because it can lead to failure during creep and can lead to embrittlement as a result of radiation damage. Two major types of cavity are usually distinguished: The term bubble is applied to a cavity which contains gas at a pressure which is at least sufficient to support the surface tension (2g/r for a spherical bubble of radius r and surface energy g). The term void is generally applied to any cavity which contains less gas than this, but is not necessarily empty of gas. A void would therefore tend to shrink in the absence of any imposed driving force for growth, whereas a bubble would be stable or would tend to grow. It is widely considered that cavity nucleation always requires the presence of one or more gas atoms. However since it is extremely difficult to prepare experimental materials with a gas impurity concentration lower than their eventual cavity concentration there is little to be gained by debating this point.

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Introductory Remarks

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600002646 ◽

1980 ◽

Vol 38 ◽

pp. 598-599

Author(s):

H. Mohri

Keyword(s):

Muscle Contraction ◽

Experimental Evidence ◽

Sea Urchin ◽

Constant Length ◽

Thin Filaments ◽

Bridge Formation ◽

Thick Filaments ◽

Sliding Mechanism ◽

Radial Spokes ◽

Cilia And Flagella

In 1959, Afzelius observed the presence of two rows of arms projecting from each outer doublet microtubule of the so-called 9 + 2 pattern of cilia and flagella, and suggested a possibility that the outer doublet microtubules slide with respect to each other with the aid of these arms during ciliary and flagellar movement. The identification of the arms as an ATPase, dynein, by Gibbons (1963)strengthened this hypothesis, since the ATPase-bearing heads of myosin molecules projecting from the thick filaments pull the thin filaments by cross-bridge formation during muscle contraction. The first experimental evidence for the sliding mechanism in cilia and flagella was obtained by examining the tip patterns of molluscan gill cilia by Satir (1965) who observed constant length of the microtubules during ciliary bending. Further evidence for the sliding-tubule mechanism was given by Summers and Gibbons (1971), using trypsin-treated axonemal fragments of sea urchin spermatozoa. Upon the addition of ATP, the outer doublets telescoped out from these fragments and the total length reached up to seven or more times that of the original fragment. Thus, the arms on a certain doublet microtubule can walk along the adjacent doublet when the doublet microtubules are disconnected by digestion of the interdoublet links which connect them with each other, or the radial spokes which connect them with the central pair-central sheath complex as illustrated in Fig. 1. On the basis of these pioneer works, the sliding-tubule mechanism has been established as one of the basic mechanisms for ciliary and flagellar movement.

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