The presence of the long-lived radionuclides Cs and Sr in ecosystems is a major environmental concern because bioavailable forms of the radionuclides are readily transferred to living organisms. The present study investigated how holometabolous insect development influences the fate of radiocaesium and radiostrontium by examining the behaviour of tracers (Cs and Sr) and stable elements during the larval feeding stage (21-23 days old), the pupal stage, and the adult stage. We aimed to evaluate the degree to which an herbivore or a detritivore food chain could serve as transfer pathways to higher trophic levels in terms of accumulation potential, and during which stage of development the accumulation potential is highest.
View Article and Find Full Text PDFThe role of insects in the transfer of radionuclides has received little attention, despite their key role in nutrient cycling within ecosystems. In this study, we investigated the trophic food chain transfer of radiocaesium (Cs) from reindeer meat to the blowfly Calliphora vicina (Robineau-Desvoidy) (Diptera: Calliphoridae) and further from blowfly pupae to the parasitoid wasp Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae). Radiocaesium was transferred to blowfly larvae during their feeding stage, with the highest whole-organism to food source concentration ratios (CR) being found in actively feeding third instar blowfly larvae, with CR in the range of 0.
View Article and Find Full Text PDFClimate change is altering the world's ecosystems through direct effects of climate warming and precipitation changes but also indirectly through changes in biotic interactions. For instance, climate-driven changes in plant and/or insect communities may alter plant-pollinator interactions, thereby influencing plant reproductive success and ultimately population dynamics of insect-pollinated plants. To better understand how the importance of insect pollination for plant fruit set varies with climate, we experimentally excluded pollinators from the partly selfing keystone species along elevational gradients in the forest-tundra ecotone in central Norway.
View Article and Find Full Text PDF