Dispersal is a biological process performed in three stages: emigration, transfer and immigration. Intra-specific variation on dispersal behavior, such as sex-bias, is very common in nature, particularly in birds and mammals. However, dispersal is difficult to measure in the field and many hypotheses concerning the causes of sex-biased dispersal remain without empirical confirmation. An importa...

1. The theory of food-regulated self-thinning (FST) for mobile animals predicts population density (N) to be an inverse function of mean body mass (W) scaled to an exponent (b), such that Nˆ kWÿb, where k is a constant. FST also predicts energy requirements (or energy ̄ow) to remain constant over time (termed energetic equivalence) as losses to cohorts (e.g. emigration and mortality) are balance...

The group IV cytoplasmic protein-tyrosine kinase Fer has been linked to cellular signaling responses to many different stimuli, including growth factors and cytokines. However, the biological relevance of Fer activation in vivo has not been demonstrated to date. Recently, we generated a transgenic mouse line in which Fer protein is expressed but lacks catalytic activity. Homozygous mutant mice ...