Experimental evidence for trait utility of gill raker number in adaptive radiation of a north temperate fish.

North temperate fish in post-glacial lakes are textbook examples for rapid parallel adaptive radiation into multiple trophic specialists within individual lakes. Speciation repeatedly proceeded along the benthic-limnetic habitat axis, and benthic-limnetic sister species diverge in the number of gill rakers. Yet, the utility of different numbers of gill rakers for consuming benthic vs. limnetic food has only very rarely been experimentally demonstrated. We bred and raised families of a benthic-limnetic species pair of whitefish under common garden conditions to test whether these species (i) show heritable differentiation in feeding efficiency on zooplankton, and (ii) whether variation in feeding efficiency is predicted by variation in gill raker numbers. We used zooplankton of three different size classes to investigate prey size dependency of divergence in feeding efficiency and to investigate the effect strength of variation in the number of gill rakers. Our results show strong interspecific differences in feeding efficiency. These differences are largest when fish were tested with the smallest zooplankton. Importantly, feeding efficiency is significantly positively correlated with the number of gill rakers when using small zooplankton, also when species identity is statistically controlled for. Our results support the hypothesis that a larger number of gill rakers are of adaptive significance for feeding on zooplankton and provide one of the first experimental demonstrations of trait utility of gill raker number when fish feed on zooplankton. These results are consistent with the suggested importance of divergent selection driven feeding adaptation during adaptive radiation of fish in post-glacial lakes.

Adaptive plasticity and genetic divergence in feeding efficiency during parallel adaptive radiation of whitefish (Coregonus spp.).

Parallel phenotypic divergence in replicated adaptive radiations could either result from parallel genetic divergence in response to similar divergent selection regimes or from equivalent phenotypically plastic response to the repeated occurrence of contrasting environments. In post-glacial fish, replicated divergence in phenotypes along the benthic-limnetic habitat axis is commonly observed. Here, we use two benthic-limnetic species pairs of whitefish from two Swiss lakes, raised in a common garden design, with reciprocal food treatments in one species pair, to experimentally measure whether feeding efficiency on benthic prey has a genetic basis or whether it underlies phenotypic plasticity (or both). To do so, we offered experimental fish mosquito larvae, partially burried in sand, and measured multiple feeding efficiency variables. Our results reveal both, genetic divergence as well as phenotypically plastic divergence in feeding efficiency, with the phenotypically benthic species raised on benthic food being the most efficient forager on benthic prey. This indicates that both, divergent natural selection on genetically heritable traits and adaptive phenotypic plasticity, are likely important mechanisms driving phenotypic divergence in adaptive radiation.

Evidence of neutral and adaptive genetic divergence between European trout populations sampled along altitudinal gradients.

Species with a wide geographical distribution are often composed of distinct subgroups which may be adapted to their local environment. European trout (Salmo trutta species complex) provide an example of such a complex consisting of several genetically and ecologically distinct forms. However, trout populations are strongly influenced by human activities, and it is unclear to what extent neutral and adaptive genetic differences have persisted. We sampled 30 Swiss trout populations from heterogeneous environments along replicated altitudinal gradients in three major European drainages. More than 850 individuals were genotyped at 18 microsatellite loci which included loci diagnostic for evolutionary lineages and candidate markers associated with temperature tolerance, reproductive timing and immune defence. We find that the phylogeographic structure of Swiss trout populations has not been completely erased by stocking. Distinct genetic clusters corresponding to the different drainages could be identified, although nonindigenous alleles were clearly present, especially in the two Mediterranean drainages. We also still detected neutral genetic differentiation within rivers which was often associated with the geographical distance between populations. Five loci showed evidence of divergent selection between populations with several drainage-specific patterns. Lineage-diagnostic markers, a marker linked to a quantitative trait locus for upper temperature tolerance in other salmonids and a marker linked to the major histocompatibility class I gene were implicated in local adaptation and some patterns were associated with altitude. In contrast, tentative evidence suggests a signal of balancing selection at a second immune relevant gene (TAP2). Our results confirm the persistence of both neutral and potentially adaptive genetic differences between trout populations in the face of massive human-mediated dispersal.

A pyrosequencing assay for the rapid discrimination of mitochondrial lineages in the Salmo trutta species complex.

The European trout (Salmo trutta species complex) is genetically very diverse consisting of five distinct mitochondrial lineages that probably originated in the Pleistocene. Here, we describe a novel pyrosequencing protocol to generate two short sequence reads from the mitochondrial control region, which allow the unambiguous identification of all five lineages. The approach was found to be easily transferable between laboratories and should be a valuable tool for the assessment of genetic diversity in trout. Pyrosequencing-based assays for molecular species identification are expected to be generally useful whenever multiple positions in a short DNA sequence need to be assessed.

Parental perceptions of childhood illness.

This article takes parental perception as the starting point of an analysis of the relationship between ill children, their families, and their doctors in the handling of a child's illness. A modified version of Creer, Marion, and Creer's Asthma Problem Behavior Checklist, adapted to suit Italian conditions, was used. The questionnaire was given to a sample of 460 parents of 230 preadolescent children. The sample was divided into two groups: The first sample was comprised of 84 parents of 42 preadolescent children with atopic symptoms (asthma, bronchitis, or hay fever), and the second sample was comprised of 376 parents of 188 preadolescents who had never had either atopic disturbances or any other serious disease. The results showed that both groups of parents felt their children were capable of autonomously managing their disease, and that they see medical facilities as their primary resource. Children were not perceived as being altered by their illness, although their illness undoubtedly affected family relationships; this was particularly true in the case of families with members who experience atopic problems. The factors causing the greatest difficulties were: disagreements over treatment, anxiety caused by the disease, and the sacrifices made by family members as a result of illness.

[Chlordesmethyldiazepam as an anesthesia-inducing agent: time of loss of consciousness. Statistical analysis in man]. / Il clordemetildiazepam come farmaco ipnoinducente: tempo di perdita di coscienza. Analisi statistica nell'uomo.

.1 mg/kg e.v. of chlordesmethyldiazepam, a 1.4 benzodiazepine derivative, were given in induction of anaesthesia of 60 plastic-reconstructive surgery patients respectively in 30 (Group 1.30 patients) and in 60 sec (Group 2.30 patients) to assess the times to spontaneous closing of the eyes and to disappearance of the palpebral reflex. It is concluded that the reflex times are not significantly different in both groups.