Population structure and pattern of geographic variation in Muscari comosum along its range of distribution

Genetic variation for six loci in 37 populations of Muscari comosum L. (Liliaeeae) is surveyed. One locus is monomorphic and identical in all the populations. The remaining loci are polymorphic. Although the GOT-1 and GOT-3 loci show a pronounced heterozygote deficit explained by selection acting upon these loci (or on genes linked to them), the remaining loci nearly conform to Hardy-Weinberg proportions. The overall pattern shows a low level of heterozygote deficit (F_IS=0.08) explained by the mixed mating system. The organization of genetic variation shows a low level of interpopulation differentiation (F_ST or G_ST=0.04). At the same time, autocorrelation analysis shows no pattern of geographical variation. It is concluded that gene flow and selection interact to produce the overall pattern of genetic variation.     

Growth and nutritional condition of the larvae of Odontesthes microlepidotus (Atherinidae): an experimental approach

Synopsis The relation between the feeding and mortality of fish larvae is mediated not only by starvation but also by their growth. In this work, daily otolith ring deposition was analysed in laboratory-reared larvae of Odontesthes microlepidotus (Jenyns), and their growth was studied in relation to ring number and otolith diameter. The nutritional condition of these larvae was assessed by means of morphometric comparisons between fed and starved larvae in order to develop a tool to evaluate the nutritional status of larvae in breeding areas. Changes in body shape have been found as a consequence of starvation. No dependence was found between mean hepatocyte nuclear area and fasting.     

Photoinhibition,photo-ecophysiology,and biophysics,a special issue in honor of Wah Soon Chow

Photosynthesis Research - Abnormally altered precipitation patterns induced by climate change have profound global effects on crop production. However, the plant functional responses to various...     

Human growth hormone as an activator for lecithin--cholesterol acyl-transferase.

The human growth hormone, intravenously administered, exhibits antilipolytic action as well as a diabetogenic effect; it leads to an increase in the activity of lecithin-cholesterol acyl-transferase.     

Behavioural mechanisms that undermine species envelope models: the causes of patchiness in the distribution of great bustards Otis tarda in Spain

Despite the general success of species envelope models, capturing the fine-scale detail of patchiness in the distributions of some species is problematic. For great bustards in Spain, apparently suitable habitat patches remain unoccupied and cannot be distinguished from occupied patches in current distribution models. We consider philopatry and conspecific attraction as main behavioural mechanisms which could account for this patchiness, and then look for evidence of their influence on the distribution of great bustards across the whole of Spain. We compared the characteristics of habitat patches classed as suitable by a distribution model according to whether they were actually used or not. Occupied patches were larger than unoccupied patches and over-used in proportion to their size, suggesting aggregation and a metapopulation structure. Arguing that conspecific attraction may serve to transfer information about site history and environmental predictability (at least over a short time period), we compared the coefficients of variation in time-series of vegetation and climatic factors at occupied and unoccupied sites. Great bustards chose sites which were more environmentally stable at critical periods in the breeding cycle, "public information" that can only be gained from others rather than through sampling. There is thus evidence that both metapopulation dynamics and conspecific attraction influence the large scale distribution of great bustards in Spain. We discuss how alternative predictor variables and multi-stage analyses may help us to incorporate behavioural mechanisms into distribution models, but acknowledge that there are limits to the value of species envelope models for animal species making decisions.