Social and seasonal plasticity of the electric fish, Brachyhypopomus gauderio

The South American electric knifefish, Brachyhypopomus gauderio, uses weakly electric fields to see and communicate in the dark. Only one study to date has investigated natural behavior in this species during the breeding season; this study proposed that B. guarerio has an exploded lek polygyny breeding system. To test this hypothesis, artificial marshes simulating the native vegetation, temperature, and water conductivities of the South American subtropics were created to study seasonal variation in associative behavior of B. gauderio during the breeding and non-breeding seasons. Mark/recapture methods were used to keep track of individual fish and their dispersion inside the experimental designs. The experimental design proved to be extremely successful at eliciting reproduction. Differences were found in seasonal variations of social behaviors between adult and juvenile populations. Although no apparent sex. differences in movement patterns were found during the breeding season; a trend for male-male aversion was found, suggesting male-male avoidance as a possible strategy guiding aspects of social behaviors in this species. Further, movement may be a tactic for mate seeking as the individuals who moved the most during the breeding season obtained the most opposite sex interactions. These findings support the exploded lek polygyny model. Social interactions are subject to complex regulation by social, physiologic and ecological factors; the extent to which these associations are repeatable may provide novel insights on the evolution of sociality as it has been shaped by natural selection.

Introducing "Fourth Space" : Young Muslims Negotiating Marriage in Europe

Based on interviews with young persons in two national Muslim youth organizations in Europe, this article examines how young Muslims negotiate between the cultural customs of their societiesof origin, their everyday experiences in Europe, and the global Muslim public sphere. In seekinga universal “true” core of Islam, these young persons create their own version of Islam, a “fourthspace” in which they reinterpret the authoritative source texts of Islam in light of personal diasporicexperiences in Europe. This reinterpretation becomes particularly pertinent in the context of planningfor future marriage, where they jointly construct new understandings of Islam to argue for inter-ethnic marriages and later age at marriage, to argue against coercion in arranged marriages, tooppose polygyny and to portray the stigmatization of divorce as counter to the true spirit of Islam.