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

Supply and demand largely determine the price of goods on human markets. It has been proposed that in animals, similar forces influence the payoff distribution between trading partners in Sexual selection, intraspecific cooperation and interspecific mutualism. Here we present the first experimental evidence supporting biological market theory in it study on cleaner fish, Labroides dimidiatus. Cleaners interact with two classes of clients: choosy client species with access to several cleaners usually do not queue for service and do not return if ignored, while resident client species with access to only one cleaning station do queue or return. We used plexiglas plates with equal amounts of food to stimulate these behaviours of the two client classes. Cleaners soon inspected 'choosy' plates before 'resident' plates. This supports previous field observations that suggest that client species with access to several cleaners exert choice to receive better(immediate) service.

Mating Intelligence, Self-Esteem, Self-Perceived Attractiveness, And Partner Choice

The present research was conducted in two studies. The first study examined how mating intelligence, self-esteem, and self-perceived attractiveness are related to each other. The second study examined how these three constructs relate to partner choice. It was hypothesized that participants who score high on mating intelligence will also score high on self-esteem and self-perceived attractiveness. Furthermore, those that score high on self-esteem will also score high on self-perceived attractiveness. It was expected that the results would be more significant for women than for men. For the second study, it was hypothesized that participants who score high on all three constructs will be more likely to select the attractive partner. The results did not show a significant interaction between mating intelligence, self-esteem, and self-perceived attractiveness. They also did not indicate higher significance levels for women. However, there were significant effects between the constructs. Additionally, participants with an average or a high score on mating intelligence were more likely to select the attractive partner.

Cdc42 explores the cell periphery for mate selection in fission yeast.

How cells polarize in response to external cues is a fundamental biological problem. For mating, yeast cells orient growth toward the source of a pheromone gradient produced by cells of the opposite mating type. Polarized growth depends on the small GTPase Cdc42, a central eukaryotic polarity regulator that controls signaling, cytoskeleton polarization, and vesicle trafficking. However, the mechanisms of polarity establishment and mate selection in complex cellular environments are poorly understood. Here we show that, in fission yeast, low-level pheromone signaling promotes a novel polarization state, where active Cdc42, its GEF Scd1, and scaffold Scd2 form colocalizing dynamic zones that sample the periphery of the cell. Two direct Cdc42 effectors--actin cables marked by myosin V Myo52 and the exocyst complex labeled by Sec6 and Sec8--also dynamically colocalize with active Cdc42. However, these cells do not grow due to a block in the exocytosis of cell wall synthases Bgs1 and Bgs4. High-level pheromone stabilizes active Cdc42 zones and promotes cell wall synthase exocytosis and polarized growth. However, in the absence of prior low-level pheromone signaling, exploration fails, and cells polarize growth at cell poles by default. Consequently, these cells show altered partner choice, mating preferentially with sister rather than nonsister cells. Thus, Cdc42 exploration serves to orient growth for partner selection. This process may also promote genetic diversification.

Fluorescence behavioral imaging (FBI) tracks identity in heterogeneous groups of Drosophila.

Distinguishing subpopulations in group behavioral experiments can reveal the impact of differences in genetic, pharmacological and life-histories on social interactions and decision-making. Here we describe Fluorescence Behavioral Imaging (FBI), a toolkit that uses transgenic fluorescence to discriminate subpopulations, imaging hardware that simultaneously records behavior and fluorescence expression, and open-source software for automated, high-accuracy determination of genetic identity. Using FBI, we measure courtship partner choice in genetically mixed groups of Drosophila.

Mycorrhizal ecology and evolution: the past, the present, and the future.

1406 I. 1407 II. 1408 III. 1410 IV. 1411 V. 1413 VI. 1416 VII. 1418 1418 References 1419 SUMMARY: Almost all land plants form symbiotic associations with mycorrhizal fungi. These below-ground fungi play a key role in terrestrial ecosystems as they regulate nutrient and carbon cycles, and influence soil structure and ecosystem multifunctionality. Up to 80% of plant N and P is provided by mycorrhizal fungi and many plant species depend on these symbionts for growth and survival. Estimates suggest that there are c. 50 000 fungal species that form mycorrhizal associations with c. 250 000 plant species. The development of high-throughput molecular tools has helped us to better understand the biology, evolution, and biodiversity of mycorrhizal associations. Nuclear genome assemblies and gene annotations of 33 mycorrhizal fungal species are now available providing fascinating opportunities to deepen our understanding of the mycorrhizal lifestyle, the metabolic capabilities of these plant symbionts, the molecular dialogue between symbionts, and evolutionary adaptations across a range of mycorrhizal associations. Large-scale molecular surveys have provided novel insights into the diversity, spatial and temporal dynamics of mycorrhizal fungal communities. At the ecological level, network theory makes it possible to analyze interactions between plant-fungal partners as complex underground multi-species networks. Our analysis suggests that nestedness, modularity and specificity of mycorrhizal networks vary and depend on mycorrhizal type. Mechanistic models explaining partner choice, resource exchange, and coevolution in mycorrhizal associations have been developed and are being tested. This review ends with major frontiers for further research.

Critérios utilizados na seleção de parceiras amorosas em relacionamentos de curto e longo prazo entre mulheres de orientação homossexual em idade reprodutiva

Diferentes critérios utilizados para a escolha de parceiros entre homens e mulheres têm sido identificados. Essa diferença, provavelmente, origina-se pelos diferentes graus de investimento parental entre gêneros. Mulheres parecem ter predisposição a selecionar parceiros com características de investimento emocional, material e com bons indicativos de saúde. Já homens podem utilizar os mesmos critérios que as mulheres, porém dão mais importância que estas à aparência física e juventude. Em relacionamentos de curto e longo prazo a literatura indica que há uma diferença nas escolhas entre mulheres. No primeiro caso, elas têm demonstrando preferir características relacionadas à saúde física, comparado ao segundo tipo de relacionamento, no qual a ênfase tem sido voltada à parceiros bons provedores de recursos e com alto nível de investimento emocional. Há poucas pesquisas que investigaram os critérios que mulheres homossexuais utilizam na escolha de suas parceiras amorosas. Estudos que investigaram a origem da homossexualidade apontaram a possibilidade de influências biológicas. Em termos evolutivos, a homossexualidade poderia ter surgido, em parte, como subproduto da evolução do prazer característico das atividades sexuais. Se esta hipótese estiver correta, o potencial para o desenvolvimento de uma orientação homo, hetero ou bissexual pode ser potencializado por ambientes característicos dos indivíduos em particular. Tal hipótese pode sugerir que os mecanismos psicológicos para escolha de parceiros sejam semelhantes entre as mulheres de variadas orientações sexuais. Para testar esta hipótese, investigou-se as preferências na escolha de parceiras de 100 mulheres em período reprodutivo, entre 18 e 40 anos, que se auto-classificaram como “homossexual exclusivo” ou “homossexual, e às vezes heterossexual”. Para a coleta de dados foram utilizados dois instrumentos, um para seleção das participantes e outro para a coleta de informações. O instrumento de coleta de dados foi dividido em: 1) Dados Demográficos; 2) Dados da parceira; 3) Critérios valorizados na escolha de uma parceira; 4) Critérios valorizados na escolha de uma parceira de curto e longo prazo; 5) Variáveis relacionadas ao desempenho sexual. As participantes foram contatadas pelo método a) “snow ball”, b) bares frequentados por grupos homossexuais e c) associações GLBT. Especificamente, investigou-se as variáveis envolvidas na escolha de parceiras de curto e longo prazo e comparou-se os resultados com os dados coletados por Cruz (2009), com mulheres heterossexuais em período reprodutivo. Os resultados indicaram que há maior preferência por atributos físicos em relacionamentos de curto prazo entre mulheres homo e heterossexuais. Atributos referentes à formação de vínculo foram mais solicitados em relacionamentos de longo prazo, possivelmente porque 75,6% dessas mulheres têm renda e não dependem do parceiro(a) para o provimento na relação, diminuindo a necessidade de parceiro(a)s que invistam recursos materiais. Mulheres homossexuais parecem ter os mesmos padrões de escolha de parceiros que heterossexuais.

Realidade ou ficção? A influência da autopercepção como parceiro romântico e da autoestima na escolha e preferência de parceiros românticos

In general, men and women look for characteristics that can indicate improvement of their reproductive success in their romantic partners. However, partner choice is not only based on what the individual want in a partner, but he/she also takes into consideration how they perceive themselves in a determined environment, in a way that self-perception can change according to the context where the individual is inserted in. Besides the environment, self-esteem can be a factor that modifies romantic partner preferences and the way that people choose these partners for being able to influence how people evaluate themselves. Most of the studies that originate today’s universal standards in the study of romantic partner were conducted with undergraduate students, which may limit the coverage of the conclusions for contemplating people of the same educational level and probably also socioeconomic status (SES). The present research, held in Brazil, where the social inequality rate is high, and part in Canada, country with low social inequality, had as goal verifying romantic partners preferences and choices and self-evaluation as romantic partners in different educational level and SES. Men, mainly of low SES, tend to prioritize social status when looking for a romantic partner while the universal pattern is the preference for physical attractiveness, and women of low SES seem to be aware of this preference when expressing that social status is important for their self-perception. In addition, the results corroborate the influence of the context, selfesteem, and SES in the self-perception as a romantic partner, though the latter two appear to modulate how the is the influence of the context on participants’ perception. Moreover, this research also indicated that the preferences appear to represent the choices for the most important characteristics for each sex, being the other characteristics probably modulated by the quantity of available participants in the environment.

Características preferidas por hombres y mujeres que buscan pareja estable de su mismo sexo

Las preferencias en elección de pareja de hombres y mujeres interesados en establecer relaciones a largo plazo con personas de su mismo sexo biológico ha sido un tema de interés para el análisis evolucionista, ya que existe debate frente a los resultados de las investigaciones y los planteamientos de las teorías de inversión parental y estrategias sexuales. Con el objetivo de identificar qué características son preferidas por hombres y mujeres interesados en establecer una relación a largo plazo con personas de su mismo sexo biológico y contribuir a esta discusión, se llevó a cabo un estudio descriptivo en el que analizamos el contenido de 732 perfiles de hombres y mujeres (H=491; M=241) que buscaban una relación estable con parejas de su mismo sexo biológico. Las categorías analizadas fueron: edad, atractivo físico (apariencia, contextura, estatura y peso), estatus socioeconómico (situación laboral, nivel educativo y zona de residencia buscada), estado civil, número de hijos y hábitos saludables (fumar y beber). Los resultados encontrados muestran que los hombres presentan rangos amplios en las características deseadas en una pareja (edad=16.87; estatura=11.37; peso=15.23) y además buscan personas menores a la edad ofrecida (M=-4.17 años). En las mujeres se encontró que los rangos son más restringidos (edad=13.85; estatura=9.83; peso=12.77) y además prefieren parejas mayores (M=2.89 años). A nivel general, se evidencia que los resultados encontrados en la mayoría de las variables podrían indicar congruencia con los planteamientos de la teoría de inversión parental y estrategias sexuales; sin embargo, en otras variables los resultados no son claros.

Finding a school technological partner: a multicriteria method for school information system producer selection

The choice of an information systems is a critical factor of success in an organization's performance, since, by involving multiple decision-makers, with often conflicting objectives, several alternatives with aggressive marketing, makes it particularly complex by the scope of a consensus. The main objective of this work is to make the analysis and selection of a information system to support the school management, pedagogical and administrative components, using a multicriteria decision aid system – MMASSITI – Multicriteria Method- ology to Support the Selection of Information Systems/Information Technologies – integrates a multicriteria model that seeks to provide a systematic approach in the process of choice of Information Systems, able to produce sustained recommendations concerning the decision scope. Its application to a case study has identi- fied the relevant factors in the selection process of school educational and management information system and get a solution that allows the decision maker’ to compare the quality of the various alternatives.

Communication and choice in yeast mating

Dissertação apresentada para obtenção do grau de doutor em Biologia de Sistemas pelo Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa.

Choice of partners in multiple two-person prisoner's dilemma games: An experimental study

We examine the effect of unilateral and mutual partner selection in the context of prisoner's dilemmas experimentally. Subjects play simultaneously several finitely repeated two-person prisoner's dilemma games. We find that unilateral choice is the best system. It leads to low defection and fewer singles than with mutual choice. Furthermore, with the unilateral choice setup we are able to show that intendingdefectors are more likely to try to avoid a match than intending cooperators. We compare our results of multiple games with single game PD-experiments and find no difference in aggregate behavior. Hence the multiple game technique is robust and might therefore be an important tool in the future for testing the use of mixed strategies.

International Partner Management in the Software Industry

The purpose of this research is to describe how the scope of internationalization affects partner management in software companies. The effects are analyzed separately for small and large companies. Partner management is described from three perspectives: who should manage partnerships, how they should be managed and how does the context affect the choice of management style. Inductive case study is selected as research design. Eventually four case companies are chosen. The findings reveal that the size of the company affects the volume whereas the scope of internationalization affects the choice of partner management activities. Companies with high scope of internationalization required a more formal yet flexible management system whereas companies with low scope of internationalization relied more on the informal relations and personal management.

International research partnerships: establishing partner selection criteria in the university-university context

The main objective of the study was to identify and evaluate criteria for international partner selection in university-university context. This study attempted at promoting better understanding of how universities should proceed in selecting partners for producing joint research publications. Thus, the aim of the study was to gain an understanding of how research collaborations can be developed and how partners can be selected. The choice of a right partner has been identified as a precondition for partnership success. In international research collaborations partnering scientists with different skills and backgrounds bring together complementary knowledge into research projects, which in most cases results in a higher quality output. Therefore, prior to selecting a partner, the set of criteria should be established. This research examined twelve Russian universities with the status of national research university as potential partners for Lappeenranta University of Technology, and selected the most appropriate universities based on established set of criteria. Potential partners’ evaluation was done using secondary sources by tracking partners’ academic success during the period 2005 – 2010. Based on established criteria, the study calculated the partnership index for each university. The results of the research reveal that among twelve examined universities there are four potential partners who have been rather active in publishing scientific articles during 2005 – 2010.