Fertile diploid males in the ant Cataglyphis cursor: a potential cost of thelytoky?

Under the hymenopteran single-locus complementary sex-determination system, production of diploid males results from homozygosity at the sex-determiner locus. This arises when both parents transmit identical alleles at the locus to the offspring. In species reproducing asexually through thelytokous parthenogenesis, production of diploid males may also occur when the sex locus undergoes recombination and becomes homozygous in the offspring. Diploid males represent a substantial genetic load in hymenopteran populations because they often produce unviable sperm or sire sterile triploid female offspring. In the Mediterranean ant Cataglyphis cursor, the queen and workers can produce female offspring through automictic thelytokous parthenogenesis with central fusion, a mode of parthenogenesis that increases homozygosity. We report, for the first time, the presence of about 39 % of colonies producing adult diploid males (seven colonies out of 18). Overall, 8 % of adult males were diploid (12 diploid males out of the 146 males genotyped). Genotyping workers from the seven colonies producing diploid males showed that three diploid males were sons of queens and produced by thelytoky, six were probably sons of workers also produced by thelytoky and three were non-natal. Furthermore, the mating of a diploid male with two virgin queens in the laboratory led to the production of sterile triploid workers, which shows that diploid males in C. cursor are fertile, mate successfully and produce viable and functional but probably sterile female offspring. Because diploid males originate from thelytokous reproduction, they are only produced during sexual production and hence do not impair colony growth, which could explain why they are not removed at early brood stages.     

Foliar uptake and metal(loid) bioaccessibility in vegetables exposed to particulate matter

At the global scale, high concentrations of particulate matter (PM) enriched with metal(loid)s are currently observed in the atmosphere of urban areas. Foliar lead uptake was demonstrated for vegetables exposed to airborne PM. Our main objective here was to highlight the health risk associated with the consumption of vegetables exposed to foliar deposits of PM enriched with the various metal(loid)s frequently observed in the atmosphere of urban areas (Cd, Sb, Zn and Pb). Leaves of mature cabbage and spinach were exposed to manufactured mono-metallic oxide particles (CdO, Sb₂O₃ and ZnO) or to complex process PM mainly enriched with lead. Total and bioaccessible metal(loid) concentrations were then measured for polluted vegetables and the various PM used as sources. Finally, scanning electronic microscopy coupled with energy dispersive X-ray microanalysis was used to study PM–phyllosphere interactions. High quantities of Cd, Sb, Zn and Pb were taken up by the plant leaves. These levels depended on both the plant species and nature of the PM, highlighting the interest of acquiring data for different plants and sources of exposure in order to better identify and manage health risks. A maximum of 2 % of the leaf surfaces were covered with the PM. However, particles appeared to be enriched in stomatal openings, with up to 12 % of their area occupied. Metal(loid) bioaccessibility was significantly higher for vegetables compared to PM sources, certainly due to chemical speciation changes. Taken together, these results confirm the importance of taking atmospheric PM into account when assessing the health risks associated with ingestion of vegetables grown in urban vegetable crops or kitchen gardens.     

Oceanographic and biogeochemical drivers cause divergent trends in the nitrogen isoscape in a changing Arctic Ocean

Nitrogen stable isotopes (δ¹⁵N) are used to study food web and foraging dynamics due to the step-wise enrichment of tissues with increasing trophic level, but they rely on the isoscape baseline that varies markedly in the Arctic due to the interplay between Atlantic- and Pacific-origin waters. Using a hierarchy of simulations with a state-of-the-art ocean-biogeochemical model, we demonstrate that the canonical isotopic gradient of 2–3‰ between the Pacific and Atlantic sectors of the Arctic Ocean has grown to 3–4‰ and will continue to expand under a high emissions climate change scenario by the end of the twenty-first century. δ¹⁵N increases in the Pacific-influenced high Arctic due to increased primary production, while Atlantic sector decreases result from the integrated effects of Atlantic inflow and anthropogenic inputs. While these trends will complicate longitudinal food web studies using δ¹⁵N, they may aid those focussed on movement as the Arctic isoscape becomes more regionally distinct.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01635-6.     

Arsenic accumulation and physiological attributes of spinach in the presence of amendments: an implication to reduce health risk

The current study examined the effect of calcium (Ca) and ethylenediaminetetraacetic acid (EDTA) on arsenic (As) uptake and toxicity to spinach (Spinacia oleracea) as well as assessed the potential human health risks. Spinach seedlings were exposed to three levels of As (25, 125, and 250 μM) alone or together with three levels of EDTA (25, 125, and 250 μM) and Ca (1, 5, and 10 mM). The effect of EDTA and Ca was assessed in terms of As contents in roots and shoots, hydrogen peroxide production, chlorophyll contents, and lipid peroxidation. The accumulation and toxicity of As to spinach plants increased with increasing As levels in nutrient solution. Exposure to As resulted in lipid peroxidation and reduced chlorophyll contents. The highest level of As alone (250 μM) showed highest human health risk (hazard quotient of 7.09 at As-250). Addition of EDTA enhanced As accumulation by spinach, while reduced As toxicity to spinach, as well as human health risk (hazard quotient of 4.01 at As-250). Similarly, Ca significantly reduced As toxicity to spinach and the human health risks (hazard quotient of 3.79 at As-250) by reducing its accumulation in spinach. Higher levels of Ca were more effective in reducing As uptake and toxicity as well as enhancing chlorophyll contents.     

Health risk assessment of drinking arsenic-containing groundwater in Hasilpur,Pakistan: effect of sampling area,depth, and source

Environmental Science and Pollution Research - Currently, several news channels and research publications have highlighted the dilemma of arsenic (As)-contaminated groundwater in Pakistan. However,...     

Evaluation of environmental contamination by toxic trace elements in Kazakhstan based on reviews of available scientific data

Environmental Science and Pollution Research - The environmental situation concerning pollution by (eco)toxic and persistent trace elements in Kazakhstan has been investigated by analytical reviews...     

Heavy metal contamination and exposure risk assessment via drinking groundwater in Vehari,Pakistan

Environmental Science and Pollution Research - The presence of toxic substances in aquifers, particularly potentially toxic heavy metals, is an important environmental and social concern worldwide....     

Optimal allocations of agricultural intensity reveal win-no loss solutions for food production and biodiversity

Regional Environmental Change - Reconciling biodiversity conservation and food production may require the fine-tuning of both agricultural intensity and its spatial allocation. Here, we explored...     

Vermicompost addition influences symbiotic fungi communities associated with leek cultivated in metal-rich soils

In the context of urban agriculture, where soils are frequently contaminated with metal(loid)s (TM), we studied the influence of vermicompost amendments on symbiotic fungal communities associated with plants grown in two metal-rich soils. Leek (Allium porrum L.) plants were grown with or without vermicompost in two metal-rich soils characterized by either geogenic or anthropogenic TM sources, to assess the influence of pollutant origin on soil-plant transfer. Fungal communities associated with the leek roots were identified by high throughput Illumina MiSeq and TM contents were measured using mass spectrometry. Vermicompost addition led to a dramatic change in the fungal community with a loss of diversity in the two tested soils. This effect could partially explain the changes in metal transfer at the soil-AMF-plant interface. Our results suggest being careful while using composts when growing edibles in contaminated soils. More generally, this study highlights the need for further research in the field of fungal communities to refine practical recommendations to gardeners.

Graphical abstract