Can female preference drive intraspecific diversity dynamics in brown trout (Salmo trutta,L.)?

Intraspecific diversity can be strongly impacted by the dynamics of reproductive isolation during secondary contacts. The high levels of hybridisation and introgression between Atlantic and Mediterranean lineages in contemporary populations of brown trout in the Northern part of the French Alps are a good case in point. After a long period of allopatry, which one assumes has facilitated their divergent phenotypic and genetic evolution, man has removed a geographical reproductive barrier via stocking the Atlantic lineage in the Mediterranean area, thereby potentially enabling gene flow between native and non native populations. We investigate how much a prezygotic reproductive behaviour, that is female preference for male phenotype, can influence hybridisation in natural environments, using subaquatic video recording of reproduction. Our statistical model indicates that female preference appears to be largely heterogamous: females tend to select dissimilar males with respect to their own phenotype; thus, rather than acting as a barrier to gene flow, female preference is favouring gene flow between lineages that have been artificially placed in sympatry. This finding based on observational data is in agreement with previously reported genetic data, high levels of hybridisation between the lineages. We suggest that a knowledge of reproductive behaviour in natural environments is an essential tool for biodiversity managers to assess the potential risks associated with the introduction into recipient populations of non‐native lineage fish at the intraspecific level.     

Biological characteristics of the hydrological landscapes in the Bay of Biscay in spring 2009

In the present study we investigated the biogeography of macrozooplankton and fish biomass in the Bay of Biscay. In this region, we defined six different landscapes based on the hydrogeographical characteristics observed in spring 2009. We then related landscape's characteristics and environmental parameters such as light attenuation depth and chlorophyll‐a with macrozooplankton and fish acoustic biomass. Hydrodynamic structures together with coastal influences (river discharges, predation pressure and depth preference) and vertical thermohaline structure/mixing (feeding modes and ability to stay in preferred layers) appeared as the main factors determining the biological distribution. Besides, variance partitioning was used to assess the respective roles played by the hydrological environment, the geographical space and the biological environment alone, and their interactions. Results revealed that: (i) macrozooplankton and fish have a preference for different hydrogeographical landscapes; (ii) the association between hydrological conditions and geographical features, i.e. the spatial structure of the hydrological environment, plays a key role in the distribution of macrozooplankton; and (iii) prey–predator relationships have to be taken into account to provide a comprehensive characterization of habitat suitability.     

Urinary cortisol as an additional tool to assess the welfare of pregnant sows kept in two types of housing

The use of urinary cortisol (UC) as an additional tool to evaluate sows welfare was assessed in two experiments. In a preliminary methodological experiment, the kinetics of cortisol excretion in urine was studied during an Adreno Cortico Trophic Hormone (ACTH) challenge test in 10 pregnant sows. In a second experiment, 96 primiparous sows of an experimental unit were assigned to two different housing systems: 48 animals were housed in individual pens (IP) and 48 animals in collective pens (CP) with 6 animals per pen. UC was measured at the beginning and at the end of pregnancy and compared with other welfare indicators such as behaviour or skin damage. In both experiments, UC was measured using a high pressure liquid chromatography assay. In experiment 1, UC was constant on the day before injection of ACTH, with no variations related to circadian rhythm. It began to rise 2 h after the injection, peaked between 2 to 5 h after then returned to the basal concentration on the day after the injection. In experiment 2, UC concentrations were not different between CP- and IP-housed sows but they were higher in sows exhibiting the less stereotypies in comparison with sows exhibiting the most stereotypies. The results of this study suggest that UC is a good indicator of acute stress, more convenient than plasma cortisol measurement since it is a non-invasive method avoiding restraint or catheterisation of sows. They also suggest that UC could also give additional information on the assessment of chronic stress and improve the evaluation of animal welfare if used in conjunction with other welfare indicators.     

The motivations and practice-area interests of first-year French veterinary students (2005-2008)

Concerns about new trends in the veterinary profession in several industrialized countries have received significant attention recently. We conducted an online survey among first-year veterinary students enrolled between 2005 and 2008 in France's four National Veterinary Schools (Ecoles Nationales Vétérinaires [ENV]) to inquire into what determined future graduates' practice-area interests and how they built a concept of their future work. A total of 1,080 students-or 70% of first-year students-responded to the survey. These students were predominantly of middle and higher social classes and most of them lived in urban areas. About 96% of the respondents had made the ENV their first choice when taking the entrance examination. In total, 39.7% declared "vocation" as the leading factor influencing their career choice. Together, the three leading practice types (wild animals, pets, and mixed) contemplated by students after graduating amount to 64.7% of the points awarded. Practice types that are not directly related to animal health were disregarded in this analysis. The results convey both how early and how firmly the choice of the veterinary career is made. They highlight the preponderance of the image of the veterinarian as an "animal doctor," the gap between the respective proportions of practice areas in the current employment pattern of veterinarians, and the aspirations of students upon admission to the ENV. A longitudinal study after one year is needed to test whether or not these career choices change during the five years of the ENV program under the influence of teaching and extramural studies.     

Quantitative and qualitative assessment of milk production after pharmaceutical induction of lactation in the mare

The induction of lactation is performed in ruminants by steroidogenic impregnation, followed by drugs intended to increase prolactin secretion. The aim of this study was to induce lactation in barren mares and to evaluate milk production. Five treated and 5 control mares were used in June and September in year 1, and 12 mares were used in year 2. Mares were administered a vaginal pessary (500 mg altrenogest and 50 mg estradiol benzoate) for 1 week. The 2nd week, another sponge with 100 mg estradiol benzoate was administered, together with 50 mg/100 kg body weight (BW) sulpiride in oil (IM q12h). All mares were milked by hand. Drug treatment was stopped after I L was obtained. Milk production and composition and plasma prolactin concentration were measured. In year 2, the same steroid treatment was applied, but mares received sulpiride (n = 6) or domperidone (1.1 mg/kg PO q12h) (n = 6). A milking machine and oxytocin injections 1 minute before the start of milking were used. In year 1, all treated mares started milking within 1-5 days after sulpiride treatment. Mean daily milk production was 0.88 +/- 0.52 L/500 kg BW. Milk immunoglobulin G (IgG) contents increased in all mares (IgG concentration range, 14-92 g/L). Plasma prolactin increased during sulpiride treatment (range. 27.7 +/- 2.9 to 43.7 +/- 6.7 ng/mL [before] to 289.0 +/- 7.8 ng/mL during treatment, P < .001). In year 2, results were similar to those in year 1, with peak IgG concentrations ranging from 4.2 to 106.7 g/L and a larger daily milk production (3.13 +/- 0.75 with sulpiride and 3.45 +/- 0.51 L/500 kg BW with domperidone). In conclusion, lactation can be induced in mares within 2 weeks, and some mares produce good-quality colostrum.     

Molecular diversity and genome structure in modern sugarcane varieties

Summary RFLP analysis was performed on 40 sugarcane cultivated varieties. Twenty-two maize low copy DNA clones located on different regions of the 10 maize chromosomes were used as probes to survey variability among the sugarcane varieties. A total of 425 fragments, 411 of which were polymorphic, were identified for 22 probe/enzyme combinations. Each variety displayed an average of 7.28 fragments per combination, revealing the complex polyploid origin of modern sugarcane varieties. The average genetic similarity between sugarcane varieties was 0.61. Although cultivated varieties appear closely related to S. officinarum clones, the genes of S. spontaneum seem to constitute the principal component of varietal diversity. A very weak global structuring among the 40 varieties is observed, in agreement with the profuse exchanges of parental materials between sugarcane breeding stations. Traces of linkage disequilibrium can be attributed to the distribution of S. spontaneum chromosomes among sugarcane varieties. The possibility of using modern varieties as a population for detecting associations between molecular markers and agronomic traits is suggested.     

Focusing beyond the diffraction limit with far-field time reversal

We present an approach for subwavelength focusing of microwaves using both a time-reversal mirror placed in the far field and a random distribution of scatterers placed in the near field of the focusing point. The far-field time-reversal mirror is used to build the time-reversed wave field, which interacts with the random medium to regenerate not only the propagating waves but also the evanescent waves required to refocus below the diffraction limit. Focal spots as small as one-thirtieth of a wavelength are described. We present one example of an application to telecommunications, which shows enhancement of the information transmission rate by a factor of 3.     

Modelling Discharge and Sediment Yield at Catchment Scale Using Connectivity Components

Knowledge about connectivity and what affects it, through space and time, is needed for taking appropriate action at the right place and/or time by stakeholders. Various conceptual frameworks for hydrological and sediment connectivity have been developed in recent years. For most of these frameworks, the objective was to conceptualise connectivity, not necessarily to infer it from measurements. Studies focussing on measurements of connectivity have so far not been done often. Because of lack of data on connectivity, few real‐world data have been used in recent connectivity modelling studies. The aim of this study was to demonstrate that existing data can be used to assess governing factors of connectivity, and how these change over time. Data from three catchments in Navarre, Northern Spain, were used to assess factors that influence hydrologic and sediment connectivity. These factors were used as components in a linear model for discharge and suspended‐sediment yield. Three components of connectivity were distinguished: topographical, biological and soil. Changes in the topographical component for the studied periods were considered relatively small, and, therefore, kept constant. Changes in the biological component were determined using the Normalised Difference Vegetation Index. Changes in the soil component were assessed using an Antecedent Precipitation Index. Nash–Sutcliffe model efficiency coefficients were between 0·49 through 0·62 for the discharge models and between 0·23 through 0·3 for the sediment‐yield models. We recommend applying the model at smaller spatial scales than catchment scale to minimise the lumping of spatial variability in the components. Copyright © 2016 John Wiley & Sons, Ltd.     

Long-term sustainability of forest ecosystems on sandstone in the Vosges Mountains (France) facing atmospheric deposition and silvicultural change

Since the 1980s, atmospheric deposition acidity has generally decreased in European forest ecosystems. However, at many sites, little or no sign of recovery has been observed yet. Concerns are rising about the sustainability of these ecosystems because of reduced nutrients inputs in atmospheric deposition and the increase in biomass harvesting to supply bio-energy.We used a silver fir plot of the French monitoring network (RENECOFOR, site SP57) typical of the ecosystems on sandstone in the Vosges Mountains, to investigate its functioning and its response facing past and possible future changes. We (1) calculated 12-year-mean “input-output” nutrient budgets, (2) measured the change in soil exchangeable cations and anions, (3) used monitoring data to calibrate a process oriented biogeochemical model, NuCM, that was then used to (4) simulate the consequences of two main scenarios and their combinations: constant or reduced atmospheric deposition, and traditional or whole-tree harvesting.Mean term changes in exchangeable nutrients and input-output budgets showed a loss of exchangeable sulphate and base cations, the level of which depended on the method. This combined efflux induced an acidification of soil solution and an alkalinisation of the soil. The model NuCM was successfully calibrated and scenarios were implemented. A slight recovery was simulated when deposition was maintained constant but combined acid and nutrient atmospheric deposition reduction delayed recovery. Whole-tree harvesting drastically decreased soil fertility compared to traditional silviculture. Hence, biomass harvesting in forests on poor soils may counter recovery in the future.