Predation shapes sperm performance surfaces in guppies

Sperm velocity is a key determinant of competitive fertilization success in many species. Selection is therefore expected to favour the evolution of faster sperm when the level of sperm competition is high. However, several aspects can determine the direction and strength of selection acting on this key performance trait, including ecological factors that influence both sperm competition and the strength of selection acting on correlated traits that may constrain evolutionary responses in sperm velocity. Here, we determine how a key ecological variable, the level of predation, shapes sperm swimming speed across 18 Trinidadian populations of guppies ( Poecilia reticulata ). We use performance analysis, a statistical tool akin to the familiar methods of multivariate selection analyses, to determine how the level of predation influences sperm velocity (modelled as a performance trait) when accounting for correlated pre- and postcopulatory traits that are also impacted by predation. We show that predation affects the combination of pre- and postcopulatory traits that ultimately predict sperm performance. Overall, we report evidence for disruptive relationships between sperm performance and combinations of ornaments and sperm morphology, but the specific combinations of traits that predict sperm velocity depended on the level of predation. These analyses underscore the complex nonlinear interrelationships among pre- and postcopulatory traits and the importance of considering ecological factors that may ultimately change the way in which multiple traits interact to determine a trait's performance value. As such, our results are likely to be broadly applicable across systems where selection is influenced by ecological conditions.

Emotional Intelligence and Its Measurement

Emotional intelligence (EI) is used in organizational training, coaching, and graduate schools. Despite its acceptance in practical applications, researchers continue to argue about its validity. EI can be defined “as a constellation of components from within a person that enable self-awareness of and management of his/her emotions, and to be aware of and manage the emotions of others.” EI seems to exist at the performance trait or ability, self-schema and trait, and behavioral levels. Based on this multilevel view, all the conceptualizations of EI and the different measures that result are EI. Research on the behavioral level of EI—its assessment, strengths, psychometric validity, and challenges—complements that on other approaches, which have already been the subject of many academic papers.

Distribution of milk flow in Holstein Friesian and Fleckvieh cows in Croatia

The aim was to investigate the distribution of milk flow rate in Holstein Friesian and Fleckvieh cattle. Researches were made in four farms in Eastern Croatia with 534 cows. 2594 tests were made with computer milking equipment, Alfa-Laval and with digital milk flow counter made by Tru-Test Company. The measuring of milk flow rates was done from 50th to 180th day of lactation. Tests showed as expected better results among Holstein Friesian then Fleckvieh cows. The optimal distribution of milk flow rate of Holstein Friesian type was 56.58 % and Fleckvieh was only 38.91 %. The results of the investigation are discussed. The milk flow rate represents an essential performance trait and should be included into the breeding program.