Eco-evolutionary processes shaping floral nectar sugar composition.

Floral nectar sugar composition is assumed to reflect the nutritional demands and foraging behaviour of pollinators, but the relative contributions of evolutionary and abiotic factors to nectar sugar composition remain largely unknown across the angiosperms. We compiled a comprehensive dataset on nectar sugar composition for 414 insect-pollinated plant species across central Europe, along with phylogeny, paleoclimate, flower morphology, and pollinator dietary demands, to disentangle their relative effects. We found that phylogeny was strongly related with nectar sucrose content, which increased with the phylogenetic age of plant families, but even more strongly with historic global surface temperature. Nectar sugar composition was also defined by floral morphology, though it was not related to our functional measure of pollinator dietary demands. However, specialist pollinators of current plant-pollinator networks predominantly visited plant species with sucrose-rich nectar. Our results suggest that both physiological mechanisms related to plant water balance and evolutionary effects related to paleoclimatic changes have shaped floral nectar sugar composition during the radiation and specialisation of plants and pollinators. As a consequence, the high velocity of current climate change may affect plant-pollinator interaction networks due to a conflicting combination of immediate physiological responses and phylogenetic conservatism.

Signals of adaptation to agricultural stress in the genomes of two European bumblebees.

Human-induced environmental impacts on wildlife are widespread, causing major biodiversity losses. One major threat is agricultural intensification, typically characterised by large areas of monoculture, mechanical tillage, and the use of agrochemicals. Intensification leads to the fragmentation and loss of natural habitats, native vegetation, and nesting and breeding sites. Understanding the adaptability of insects to these changing environmental conditions is critical to predicting their survival. Bumblebees, key pollinators of wild and cultivated plants, are used as model species to assess insect adaptation to anthropogenic stressors. We investigated the effects of agricultural pressures on two common European bumblebees, Bombus pascuorum and B. lapidarius. Restriction-site Associated DNA Sequencing was used to identify loci under selective pressure across agricultural-natural gradients over 97 locations in Europe. 191 unique loci in B. pascuorum and 260 in B. lapidarius were identified as under selective pressure, and associated with agricultural stressors. Further investigation suggested several candidate proteins including several neurodevelopment, muscle, and detoxification proteins, but these have yet to be validated. These results provide insights into agriculture as a stressor for bumblebees, and signal for conservation action in light of ongoing anthropogenic changes.

Radiocesium (137Cs) and Mineral Elements in Culinary-Medicinal Mushrooms from the Southern Outskirts of Kyiv, Ukraine.

In recent decades, the estimation of radionuclide and heavy metal levels in culinary-medicinal mushrooms has been of interest because some of them have proven to be hyperaccumulators of toxic elements. This article presents results on radiocesium (137Cs) activity in fruit bodies of medicinal-culinary mushrooms-Agaricus sylvaticus Schaeff., Chlorophyllum rhacodes (Vitt.) Vellinga, Coprinellus micaceus (Bull.) Vilgalys, Hopple & Jacq. Johnson, Coprinopsis atramentaria (Bull.) Redhead, Vilgalys & Moncalvo, Coprinus comatus (O.F. Mull.) Pers., Fistulina hepatica (Schaeff.) With., Laetiporus sulphureus (Bull.) Murrill, Leccinum scabrum (Bull.) Gray, Macrolepiota procera (Scop.) Singer, Melanoleuca brevipes (Bull.) Pat., Pleurotus ostreatus (Jacq.) P. Kumm., Xerocomellus chrysenteron (Bull.) Sutara, nonedible Echinoderma asperum (Pers.) Bon, and toxic species Agaricus xanthodermus Genev.-collected in 2015, as well as magnesium, manganese, iron, copper, zinc, chromium, nickel, molybdenum, cadmium, selenium, lead, and mercury content in medicinal-culinary species-Armillaria mellea (Vahl) P. Kumm., Ch. rhacodes, C. comatus, Grifola frondosa (Dicks.) Gray, Gyroporus cyanescens (Bull.) Quel., L. scabrum, M. procera, P. ostreatus, and X. chrysenteron-collected during 2016-2017 on the southern outskirts of Kyiv, the capital of Ukraine. The data obtained suggest safe levels of radiocesium and some essential and toxic elements in mushroom fruit bodies. All the investigated species are collective sorbents of magnesium, manganese, copper, and zinc; thus, they represent the source of the intake of these elements in the human body. The species-specific manner of mineral element accumulation was observed. In addition to medicinal values, some species (in particular, M. procera and Ch. rhacodes) are of interest as potential informative bioindicators of heavy metal contamination of the environment.