Together with the presence of intermediate grey colour

expressed by intermediate-sized individuals, this fish could ontogenetically changes their body colour from white to black. Both sexes of black individuals selleck occupied feeding territories, but white individuals were non-territorial, indicating that the black body signals the possession of a feeding territory. Sexually active females were invariably black, whereas sexually active males were both black and white in colour. Few of the largest black males held harems, which included several female territories, whereas the remaining males were bachelors with no female territories. These bachelor males invested more in testes than harem males, suggesting that bachelors employ sneaking tactics, which is corroborated by our sneaking observations. To our knowledge, this is the first study showing that sneakers are entirely dissimilar to females in appearance. Herein,

we discuss why sneakers are dichromatic in relation to their life histories. “
“The chamois Rupicapra rupicapra has been termed a highly polygynous species, with a great male competition for mating. If so, a lower survival should be expected for the male sex. From 1986 to 2000, 1801 carcasses of chamois were collected in the Maritime Alps Regional Park, Italy, where a protected, healthy, stable population of chamois occurred (c. 12 individuals 100 ha−1). Each year, population structure from carcasses Selleckchem Alvelestat was consistent with that from the count carried out on the preceding year on live individuals. Demographic features (assessed from mortality data, as well as from live counts) showed a balanced age structure and a good adult survival (10% individuals older than 11 years). Mortality peaks showed a cyclic pattern of 3–4 years. Winter severity and local density affected survival, with no significant difference between sexes. The number of carcasses was dependent on the combination of snow depth and mean temperature, in winter. Both sexes showed nearly the same survivorship curves, with a quite similar life expectancy in the first year (males=6.8 years, females=7.0 years), and the same maximum age

at death (16 years), as it may be expected in a monomorphic, monogamous species. This is, however, a rare event selleck chemicals llc among polygynous species, with a high male competition for females and male juvenile dispersion, which normally affect male survival. The similar adult survival of the two sexes could be explained by comparable energetic costs and risks for reproduction, or through greater fat reserves put on by males, before the rut, which may lower their winter mortality. “
“Packard and colleagues investigate the prediction of the body mass of dinosaurs, using allometric models, advocating parameter estimation via direct optimization of a least-squares criterion on arithmetic axes rather than the conventional approach based on linear least-squares regression on logarithmic axes.