Exploring connections between pollinator health and human health

Biological control for One Health

Biological control has been effectively exploited by mankind since 300 CE. By promoting the natural regulation of pests, weeds, and diseases, it produces societal benefits at the food-environment-health nexus. Here we scrutinize biological control endeavours and their social-ecological outcomes through a holistic 'One-Health' lens, recognizing that the health of humans, animals, plants, and the wider environment are linked and interdependent. Evidence shows that biological control generates desirable outcomes within all One Health dimensions, mitigating global change issues such as chemical pollution, biocide resistance, biodiversity loss, and habitat destruction. Yet, its cross-disciplinary achievements remain underappreciated. To remedy this, we advocate a systems-level, integrated approach to biological control research, policy, and practice. Framing biological control in a One Health context helps to unite medical and veterinary personnel, ecologists, conservationists and agricultural professionals in a joint quest for solutions to some of the most pressing issues in planetary health.

Exposure Pathways and Toxicity of Microplastics in Terrestrial Insects

The detrimental effects of plastics on aquatic organisms, including those of macroplastics, microplastics, and nanoplastics, have been well established. However, knowledge on the interaction between plastics and terrestrial insects is limited. To develop effective strategies for mitigating the impact of plastic pollution on terrestrial ecosystems, it is necessary to understand the toxicity effects and influencing factors of plastic ingestion by insects. An overview of current knowledge regarding plastic ingestion by terrestrial insects is provided in this Review, and the factors influencing this interaction are identified. The pathways through which insects interact with plastics, which can lead to plastic accumulation and microplastic transfer to higher trophic levels, are also discussed using an overview and a conceptual model. The diverse impacts of plastic exposure on insects are discussed, and the challenges in existing studies, such as a limited focus on certain plastic types, are identified. Further research on standardized methods for sampling and analysis is crucial for reliable research, and long-term monitoring is essential to assess plastic trends and ecological impacts in terrestrial ecosystems. The mechanisms underlying these effects need to be uncovered, and their potential long-term consequences for insect populations and ecosystems require evaluation.

Biodiversity burdens in Spanish conventional and low-impact single-family homes

Biodiversity loss caused by housing is not a well-defined sector of environmental impact. This research quantifies effects on biodiversity of an average Spanish Single-Family House (SFH) with 180 m2 of built surface. The current Spanish SFH stock GWP amounts to 1.16 Gt CO2eq in a 50-year life cycle, 40 % of which is embodied in the building materials and the 60 % are emissions due to the use of the building. This stock also impacts with 10.2 Gt 1,4-DCB the land, water and human health. SFHs also drive 6052 species extinct in a 50 year life cycle, and account for 3.03 M years of life lost due to premature death or lived with a disability. Divided by the 16 M people living in Spanish SFHs, each one lost 0.19 years of their lives (68.1 days) due to their home's impacts on human health. The article compares a reference conventional building against three low-impact cases, to understand how different building techniques and materials influence environmental outcomes that keep biodiversity loss the lowest possible. Scenarios include a standard brick and concrete house as Scenario 0 (SC0, Base), a timber Passivhaus as Scenario 1 (SC1), a straw-bale house with renewable energies as Scenario 2 (SC2), and an earth bioclimatic house as Scenario 3 (SC3). An initial Global Warming Potential (GWP) analysis was performed to relate previous building Life Cycle Assessment (LCA) studies with biodiversity metrics. Three main biodiversity metrics; ecotoxicity (as midpoint indicator), biodiversity loss and damage to human health (both as endpoint indicators) have been considered. Compared to SC0 with 1292 kgCO2-eq·m-2 (516 embodied) of GWP, we found that SC1 emitted -47.0 % of that, SC2-41.4 % and SC3-80.9 %. Concerning ecotoxicity, where SC0 has 11,399 kg 1,4 DCB, the results are -27.9 % in SC1, -19.2 % in SC2, and -45.6 % in SC3. Regarding biodiversity loss, where SC0 has 7.54 E-06 species.yr·m-2, the impacts are -30.9 % in SC1, -32.6 % in SC2, and -58.6 % in SC3. Human health damage in SC0 being 3.37 E-03 DALY, has been reduced in the timber home (SC1) is -44.2 %, of the Straw SFH (SC2) -39.2 %, and of the earth house (SC3) -67.1 %. This article shows that with current existing technological solutions GWP could be reduced in -80.9 %, ecotoxicity in -45.6 %, biodiversity loss in -58.6 % and human health in -67.1 %. Spanish Single-Family Houses built in timber, earth or straw-bale are real alternatives to current cement traditional building.

Ecological interactions affect the bioactivity of medicinal plants

Essential oils produced by medicinal plants possess important bioactive properties (antibacterial, antioxidant) of high value for human society. Pollination and herbivory can modify the chemical defences of plants and therefore they may influence the bioactivity of essential oils. However, the effect of ecological interactions on plant bioactivity has not yet been evaluated. We tested the hypothesis that cross-pollination and simulated herbivory modify the chemical composition of essential oils, improving the bioactive properties of the medicinal plant Lepechinia floribunda (Lamiaceae). Through controlled experiments, we showed that essential oils from the outcrossed plant progeny had a higher relative abundance of oxygenated terpenes and it almost doubled the bacteriostatic effect on Staphylococcus aureus, compared to inbred progeny (i.e., progeny produced in absence of pollinators). Herbivory affected negatively and positively the production of rare compounds in inbred and outcrossed plants, respectively, but its effects on bioactivity still remain unknown. We show for the first time that by mediating cross-pollination (indirect ecosystem service), pollinators can improve ecosystem services linked to the biological activity of plant's essential oils. We stress the importance of the qualitative component of pollination (self, cross); an aspect usually neglected in studies of pollination services.

Global meta-analysis shows reduced quality of food crops under inadequate animal pollination

Animal pollination supports the production of a wide range of food crops fundamental to maintaining diverse and nutritionally balanced diets. Here, we present a global meta-analysis quantifying the contribution of pollination to multiple facets of crop quality, including both organoleptic and nutritional traits. In fruits and vegetables, pollinators strongly improve several commercially important attributes related to appearance and shelf life, whereas they have smaller effects on nutritional value. Pollination does not increase quality in stimulant crops, nuts, and spices. We report weak signals of a pollination deficit for organoleptic traits, which might indicate a potential service decline across agricultural landscapes. However, the deficit is small and non-significant at the α = 0.05 level, suggesting that pollen deposition from wild and/or managed pollinators is sufficient to maximise quality in most cases. As producing commercially suboptimal fruits can have multiple negative economic and environmental consequences, safeguarding pollination services is important to maintain food security.

Pesticide mixtures detected in crop and non-target wild plant pollen and nectar

Cultivation of mass flowering entomophilous crops benefits from the presence of managed and wild pollinators, who visit flowers to forage on pollen and nectar. However, management of these crops typically includes application of pesticides, the presence of which may pose a hazard for pollinators foraging in an agricultural environment. To determine the levels of potential exposure to pesticides, their presence and concentration in pollen and nectar need assessing, both within and beyond the target crop plants. We selected ten pesticide compounds and one metabolite and analysed their occurrence in a crop (Brassica napus) and a wild plant (Rubus fruticosus agg.), which was flowering in field edges. Nectar and pollen from both plants were collected from five spring and five winter sown B. napus fields in Ireland, and were tested for pesticide residues, using QuEChERS and Liquid Chromatography tandem mass spectrometry (LC-MS/MS). Pesticide residues were detected in plant pollen and nectar of both plants. Most detections were from fields with no recorded application of the respective compounds in that year, but higher concentrations were observed in recently treated fields. Overall, more residues were detected in B. napus pollen and nectar than in the wild plant, and B. napus pollen had the highest mean concentration of residues. All matrices were contaminated with at least three compounds, and the most frequently detected compounds were fungicides. The most common compound mixture was comprised of the fungicides azoxystrobin, boscalid, and the neonicotinoid insecticide clothianidin, which was not recently applied on the fields. Our results indicate that persistent compounds like the neonicotinoids, should be continuously monitored for their presence and fate in the field environment. The toxicological evaluation of the compound mixtures identified in the present study should be performed, to determine their impacts on foraging insects that may be exposed to them.

Natural processes influencing pollinator health

Evidence from the last few decades indicates that pollinator abundance and diversity are at risk, with many species in decline. Anthropogenic impacts have been the focus of much recent work on the causes of these declines. However, natural processes, from plant chemistry, nutrition and microbial associations to landscape and habitat change, can also profoundly influence pollinator health. Here, we argue that these natural processes require greater attention and may even provide solutions to the deteriorating outlook for pollinators. Existing studies also focus on the decline of individuals and colonies and only occasionally at population levels. In the light of this we redefine pollinator health and argue that a top-down approach is required focusing at the ecological level of communities. We use examples from the primary research, opinion and review articles published in this special issue to illustrate how natural processes influence pollinator health, from community to individuals, and highlight where some of these processes could mitigate the challenges of anthropogenic and natural drivers of change. This article is part of the theme issue 'Natural processes influencing pollinator health: from chemistry to landscapes'.