Only two weeks are required forTricholoma matsutake to differentiate ectomycorrhizal Hartig net structures in roots ofPinus densiflora seedlings cultivated on artificial substrate

There has been conflicting debate over many years regarding the trophic status ofTricholoma matsutake (Ito et Imai) Sing., and further investigations are necessary to better understandT. matsutake physiology, particularly carbon nutrition, during ectomycorrhizal symbiosis. For this purpose, we developed a technique to rapidly synthesizein vitro ectomycorrhizas betweenPinus densiflora Sieb. et Zucc. andT. matsutake on artificial substrate (vermiculite: perlite: peat: beech sawdust; 5:5:1:1.), without added sugar in the nutrient solution. Only 1 week was required before the first rudimentary Hartig net ‘palmetti’ could be observed in roots. Well-developed Hartig net structures appeared in taproots after 2 weeks and in lateral roots after 3 weeks. Such rapid root infection may be attributed to the quality of the substrate and the inoculum used. This research was supported by a grant from the Bio-oriented Technology Research Advancement Institution (BRAIN).     

Adaptive plasticity in female mate choice dampens sexual selection on male ornaments in the lark bunting

Theory on the evolution of ornamental male traits by sexual selection assumes consistency in selection over time. Temporal variation in female choice could dampen sexual selection, but scant information exists on the degree to which individual female preferences are flexible. Here we show that in lark buntings sexual selection on male traits varied dramatically across years and, in some cases, exhibited reversals in the direction of selection for a single trait. We show that these shifts are probably because of flexibility in mate choice by individual females and that they parallel shifts in the male traits that predict female reproductive success in a given year. Plasticity in choice and concomitant reversals in mating patterns across time may weaken the strength of sexual selection and could maintain genetic variation underlying multiple sexual ornaments.     

Late Mousterian persistence near the Arctic Circle

Palaeolithic sites in Russian high latitudes have been considered as Upper Palaeolithic and thus representing an Arctic expansion of modern humans. Here we show that at Byzovaya, in the western foothills of the Polar Urals, the technological structure of the lithic assemblage makes it directly comparable with Mousterian Middle Palaeolithic industries that so far have been exclusively attributed to the Neandertal populations in Europe. Radiocarbon and optical-stimulated luminescence dates on bones and sand grains indicate that the site was occupied during a short period around 28,500 carbon-14 years before the present (about 31,000 to 34,000 calendar years ago), at the time when only Upper Palaeolithic cultures occupied lower latitudes of Eurasia. Byzovaya may thus represent a late northern refuge for Neandertals, about 1000 km north of earlier known Mousterian sites.     

The kinetic profile of oxolinic acid in sharpsnout sea bream, Diplodus puntazzo (Cetti 1777)

The pharmacokinetics of oxolinic acid (OA) were investigated after a single intra‐vascular injection (20 mg kg^?1 fish) in sharpsnout sea bream (90 g), a promising new euryhaline species for Mediterranean fish farming. The distribution half‐life (t_1/2α) and the elimination half‐life (t_1/2β) of OA were calculated to be 0.4 and 10 h respectively. The apparent volume of distribution at steady‐state (V_d(ss)) and total clearance rate (CL_T) of the drug were found to be 2.1 L kg and 0.2 L kg^?1 h^?1 respectively. The bioavailability (F%) of OA following oral administration (40 mg kg^?1 fish) was estimated to be 15%. The results indicate a rapid distribution and elimination of the drug, moderate tissue penetration, but low absorption in sharpsnout sea bream. The kinetic profile of OA found in this species is comparable with that observed in another well‐known sparid, gilthead sea bream.     

Effect of diet composition on nutrient digestibility and digestive enzyme levels of gilthead sea bream (Sparus aurata L.)

An experiment was conducted to evaluate the effects of dietary composition on apparent digestibility coefficients of protein, fat and carbohydrate of gilthead sea bream. In addition α‐amylase and proteolytic activities were measured in the digestive tract of fish, held at 20±1°C. Six experimental diets were formulated containing approximately 40%, 45% and 50% protein, 11% and 21% fat and a starch level which fluctuated from 14% to 36%. Fish having an average weight of 100–130 g were used, fed at 1.5% of their body weight daily, and digestibility was measured using an indirect method. Enzyme activities were measured in the digestive tract of fish, fed diets containing a combination of 40%, 50% protein with 11%, 21% fat at 0.5, 5, 10, 24 h after a single meal. Starch digestibility was reduced with its level in the diet. It also negatively affected fat digestibility as well as protein digestibility, the last only at the high fat level. Dietary fat level had a negative effect on starch and protein digestibility. Fat affected also strongly α‐amylase levels in the digestive tract, while its effect on protease activity was of smaller magnitude. These results indicate that digestive enzyme activities and nutrient digestibility values are affected by dietary composition, carbohydrates and fat indicating the strongest effect.     

Myriophyllum heterophyllum Michaux [Haloragaceae] en Haute‐Vienne (Limousin,France), et situation de cette plante invasive en France et en Europe

On the 10th of July 2011, in Saint‐Sylvestre, a municipality of the Haute‐Vienne French department, an unknown aquatic plant was observed which largely covered a private pond. After a collaborative identification by the authors and the national botanical conservatory of Massif Central (CBNMC) office Limousin, it was concluded to be Myriophyllum heterophyllum Michaux. This article describes the situation of this species, which is considered an invasive alien species in Europe, but had not previously been the subject of an official report, or evaluation of its situation in France and in Europe in the natural environment.     

Observations on the increase of wild gilthead seabream,Sparus aurata abundance,in the eastern Adriatic Sea: problems and opportunities

The recent increase of the local population of gilthead seabream, Sparus aurata, in three areas along the southeastern Adriatic Sea: Malostonski Bay (Croatia and Bosnia and Herzegovina), Neretva Estuary (Croatia) and Boka Kotorska Bay (Montenegro) and its adverse effects on shellfish culture by preying on Mediterranean mussels, Mytilus galloprovincialis, and the European flat oyster, Ostrea edulis, are studied. The results from the analysis of the existing information show that the main reason for the recent increase is the escapes from local fish farm which enrich the local population constantly with new gilthead sea bream. The existence of practically endless food in the area of the shellfish farms allows the concentration of the population in the region instead of its dispersion along the Adriatic coast. Moreover, ecological analysis indicates that the gilthead seabream is facing a very low competition from other local species which enhances its capacity to further populate the region. While the impact on the ecosystem is not yet known, the socio-economic impact of the increase of the gilthead seabream population is evident today. Many shellfish farms are closing today in the region since the damages may reach over 90 % of the production.