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The concept of source-sink dynamics as a potentially important component of metapopulation dynamics was introduced in the 1980s. The objective of the present review was to review the considerable body of work that has been developed, to consider its theoretical implications as well as to understand how source-sink dynamics may manifest under field conditions in the specific case of nontarget arthropods in the agricultural environment. Our review concludes that metapopulation dynamics based on field observations are often far more complex than existing theoretical source-sink models would indicate, because they are dependent on numerous population processes and influencing factors. The difficulty in identifying and measuring these factors likely explains why empirical studies assessing source-sink dynamics are scarce. Furthermore, we highlight the importance of considering the spatial and temporal heterogeneity of agricultural landscapes when assessing the population dynamics of nontarget arthropods in the context of the risk from the use of plant protection products. A need is identified to further develop and thoroughly validate predictive population models, which can incorporate all factors relevant to a specific system. Once reliable predictive models for a number of representative nontarget arthropod species are available, they could provide a meaningful tool for refined risk evaluations (higher tier level risk assessment), addressing specific concerns identified at the initial evaluation stages (lower tier level risk assessment). Environ Toxicol Chem 2021;40:2667-2679. © 2021 ERM, FMC, Syngenta, Bayer AG, BASF SE, Corteva agriscience. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

The aim of the study was to investigate the potential impact of the insecticide chlorantraniliprole on queen-right bumblebee (Bombus terrestris) colonies under semi-field conditions in Phacelia tanacetifolia. The P. tanacetifolia crop was grown in soil treated with modelled worst-case 20-year plateau concentration of chlorantraniliprole in the top 20 cm of soil (equivalent to 0.088 mg a.s./kg). Additionally, two chlorantraniliprole spray applications at 60 g a.s./ha were made. In treatment T1 both spray applications took place before P. tanacetifolia flowering at growth stages BBCH 51–55 and BBCH 55–59. In T2 one spray application was conducted before P. tanacetifolia flowering at BBCH 55–59 and one application during P. tanacetifolia flowering and during daily bee flight at BBCH 61–62. The application in the control (C) and reference item treatment (R) (400 g dimethoate a.s./ha) was carried out during full P. tanacetifolia flowering and bumblebee flight. The bumblebee colonies were exposed to the treated flowering P. tanacetifolia crop for 20 days in the tunnels and afterwards the colonies were kept on a monitoring site. Results of this study indicate no significant differences between the chlorantraniliprole groups T1 and T2 and the control regarding all parameters assessed (i.e. adult and larval mortality, flight activity at the hive entrance, colony weight development, condition of the colonies and production of young queens and males). Overall, no effects of chlorantraniliprole on B. terrestris colonies including queen/male production, adult and larval survival, colony development and forager flight activity were found in this worst-case exposure set-up.

In the first step of earthworm risk assessment for plant protection products (PPPs), the risk is assessed by comparing the no-observed effect levels (NOELs) from laboratory reproduction tests with the predicted exposure of the PPP in soil, while applying a trigger value (assessment factor [AF]) to cover uncertainties. If this step indicates a potential risk, field studies are conducted. However, the predicted environmental concentration in soil, which can be calculated, for example, for different soil layers (ranging from 0-1 cm to 0-20 cm), and the AF determine the conservatism that is applied in this first step. In this review paper, the tier 1 earthworm risk assessment for PPPs is calibrated by comparing the NOEL in earthworm reproduction tests with effect levels on earthworm populations under realistic field conditions. A data set of 54 pairs of studies conducted in the laboratory and in the field with the same PPP was compiled, allowing a direct comparison of relevant endpoints. The results indicate that a tier 1 AF of 5 combined with a regulatory relevant soil layer of 0 to 5 cm provides a conservative tier 1 risk assessment. A risk was identified by the tier 1 risk assessment in the majority of the cases at application rates that were of low risk for natural earthworm populations under field conditions. Increasing the conservatism in the tier 1 risk assessment by reducing the depth of the regulatory relevant soil layer or by increasing the tier 1 AF would increase the number of false positives and trigger a large number of additional field studies. This increased conservatism, however, would not increase the margin of safety for earthworm populations. The analysis revealed that the risk assessment is conservative if an AF of 5 and a regulatory relevant soil layer of 0 to 5 cm is used. Integr Environ Assess Manag 2016;12:643-650. © 2015 SETAC.

Within the regulatory framework for authorisation of plant protection products (PPPs) (EU Directive 91/414/1991/EEC replaced by Regulation (EC) 1107/2009), higher tier risk assessments and earthworm field tests are conducted in different countries across Europe. This paper describes dominant earthworm species for regulatory and biogeographical regions in agricultural landscapes across Europe and examines regional differences in earthworm communities and densities and their respective response to a toxic reference. For the assessment of earthworm abundance and species distribution, data of untreated control plots from 30 earthworm field studies were analysed; each conducted according to the ISO 11268–3 (1999) guideline by European Crop Protection Association member companies in the context of registration of PPPs. For the evaluation of the response to PPPs under different regional and climatic conditions, the effect on earthworm abundance was assessed by comparing plots treated with toxic references with untreated control plots. Additionally, a comparative literature review was included providing an overview of earthworm species composition and densities in agricultural crops from 14 European countries. The assessment of earthworm field studies from six different European countries revealed that common earthworm species of anecic and endogeic ecological groups are present at most field sites. Dominant species groups of endogeic and anecic earthworms can be defined that are abundant in all assessed countries. These are the endogeic species Aporrectodea caliginosa, Aporrectodea rosea and Allolobophora chlorotica, and the anecic species Lumbricus terrestris (Northern and Central Europe) and Lumbricus friendi (Southern Europe). Taking into account the high variability in total earthworm abundances, it can be concluded that the variability within regions was larger than the variability between regions. Analysis of the earthworm community and data of toxic references lead to the conclusion that testing in different zones is not considered necessary.

The aim of this review was to assess the degree to which recent litter bag studies performed between 2002 and 2004 have followed the recommendations laid down in the ‘Effects of plant protection products on functional endpoints in soil (EPFES)’ guidance document and the Organisation for Economic Co-Operation and Development (OECD) Guidance Document on the Breakdown of Organic Matter in Litter bags (OECD, Guidance document on the breakdown of organic matter in litter bags, OECD series on testing and assessment, no 56, 36 pp, 2006), which can be required under European Union (EU) Directive 91/414/EEC (EU, Off J Eur Union, L230:1–32, 1991) for assessing the effect of plant protection products on non-target soil macro-organisms which contribute to the breakdown of organic matter. The current review covers the analysis of key parameters of the litter bag method of a total of 29 litter bag studies conducted by six European Crop Protection Association companies. The two validity criteria [i.e. 60% mass loss at the end of the study in the control and a maximum coefficient of variation of 40% for mass loss in the control plots (n = 6) during the first 6 months of the test] were met in all of the studies reviewed. In over half of the studies, more than 60% mass loss was reached in the control litter bags after about 6 months. Statistically significant effects on organic matter breakdown due to plant protection products were repeatedly observed during the first few months of the study conduct, including effects >10% up to >25% compared to the control. The survey of 29 study reports—performed from May 2002 to May 2004—showed that litter bag studies are generally being performed following the ‘EPFES’ guidance document and the OECD guidance document no. 56. Transient, statistically significant effects >10% up to >25% compared to the control were determined repeatedly during the first few months of the study conduct, thus clearly indicating the sensitivity of the litter bag test system. The litter bag study design is a valuable test system for the risk assessment of plant protection products on non-target soil macro-organisms which contribute to the breakdown of organic matter under EU Directive 91/414/EEC (EU, Off J Eur Union, L230:1–32, 1991). In general, it can be concluded that the litter bag test, as proposed by EPFES and the OECD guidance document, provides an integrative answer on the potential effects of plant protection products on organic matter breakdown in soil and can be continued to be used if the studies follow the recommendations as presented in the guidance documents closely.

In the first step of earthworm risk assessment for plant protection products (PPPs), the risk is assessed by comparing the no-observed effect levels (NOELs) from laboratory reproduction tests with the predicted exposure of the PPP in soil, while applying a trigger value (assessment factor [AF]) to cover uncertainties. If this step indicates a potential risk, field studies are conducted. However, the predicted environmental concentration in soil, which can be calculated, for example, for different soil layers (ranging from 0-1 cm to 0-20 cm), and the AF determine the conservatism that is applied in this first step. In this review paper, the tier 1 earthworm risk assessment for PPPs is calibrated by comparing the NOEL in earthworm reproduction tests with effect levels on earthworm populations under realistic field conditions. A data set of 54 pairs of studies conducted in the laboratory and in the field with the same PPP was compiled, allowing a direct comparison of relevant endpoints. The results indicate that a tier 1 AF of 5 combined with a regulatory relevant soil layer of 0 to 5 cm provides a conservative tier 1 risk assessment. A risk was identified by the tier 1 risk assessment in the majority of the cases at application rates that were of low risk for natural earthworm populations under field conditions. Increasing the conservatism in the tier 1 risk assessment by reducing the depth of the regulatory relevant soil layer or by increasing the tier 1 AF would increase the number of false positives and trigger a large number of additional field studies. This increased conservatism, however, would not increase the margin of safety for earthworm populations. The analysis revealed that the risk assessment is conservative if an AF of 5 and a regulatory relevant soil layer of 0 to 5 cm is used. Integr Environ Assess Manag 2016;12:643-650. © 2015 SETAC.

A mass rearing method for Erigone atra (Blackwall) (Araneae: Linyphiidae) allowing continuous laboratory rearing is described. Twenty 1–2-day old spiderlings were kept together in plastic boxes, which were filled with soil containing a culture of the Collembola species, Lepidocyrtus lanuginosus (Gmelin) (Entomobryidae), and serving the spiders as a continuous available prey source. Once per week vestigial-wing fruit flies of Drosophila melanogaster Meigen (Diptera: Drosophilidae) were provided as additional prey. In addition, the rearing boxes were filled with wood-wool serving spiders as points of contact for their webs. After 3–5 weeks most of the spiderlings developed to adults, which were separated individually into glass tubes filled with soil and Collembola until all of them became adult. To produce a new generation of spiders 20–40 adult/subadult spiders originating from different mass rearing boxes were brought together and kept and fed in the same way as the spiderlings. Within a few days females started to produce eggsacs. The eggsacs were transferred into glass tubes filled with a layer of moist plaster of Paris until the spiderlings hatched, which were then bred as described above. Erigone atra was bred over 12 generations within a period of 2 years. The mean rearing success (from 1 to 2-day-old spiderlings to adults) was 59.3%. Decreasing rearing success, decrease of fecundity or decrease of adult spider size were not observed. Advantages and use of the mass rearing method are discussed in relation to rearing methods for other spiders.

Intraguild predation between female erigonid spiders [Erigone atra (Blackwall) and Oedothorax apicatus (Blackwall), Araneae, Erigonidae] and lacewing larvae (second instar larvae of Chrysoperla carnea (Stephens), Neuropt., Chrysopidae) and interaction effects of predator combinations on cereal aphids were investigated in a microcosm system under laboratory conditions. The microcosm experiments were run for 7 days and consisted of 15wheat seedlings, 15 Sitobion avenae (F) (Hom., Aphididae) as start population, plus a female spider or a lacewing larva or a combination of a spider plus a lacewing larva. The mortality rate of lacewing larvae was significantly increased by 44 and 31% due to intraguild predation by female spiders of E. atra and O. apicatus in comparison with lacewing larvae that were kept alone. The final aphid numbers in the microcosms were significantly reduced by all single predator treatments (spiders, lacewing larvae) and the predator combinations in comparison with controls without predators. The predation effect on aphid populations due to both spider species was similar and not statistically different. An additive effect of the predator combinations ‘spider plus surviving lacewing larva’ was found for both spider species resulting in reduced aphid numbers compared with the single predator treatments. When the lacewing larva was killed by an E. atra female the effects on aphids were non-additive, but aphid numbers were not statistically increased compared with the lacewing larva treatment. When the lacewing larva was killed by an O. apicatus female, the effects of spider and C. carnea larva were additive on aphid numbers. In the presence of additional prey (fruit flies and Collembola) intraguild predation was not found and E. atra females had no significant effect on the survival of lacewing larvae. In addition, E. atra females had no significant effect on aphid numbers in the presence of fruit flies and Collembola, but in combination with a lacewing larva that survived, a significantly greater reduction of the aphid population was observed compared with the lacewing larva treatment. The body mass of lacewing larvae at the end of the experiment was not statistically influenced by the presence or absence of an E. atra female.

International audience; This chapter proposes a method for estimating risk to honey bees (Apis mellifera) and non-Apis bees from pesticides that are applied through sprays (acting on contact) and through seed or soil treatments and tree trunk injections (acting systemically). It describes the risk assessment process for honey bees and non-Apis bees. Problem formulation articulates the intent of the risk assessment and is predicated on particular protection goals for which the regulatory authority is responsible. The chapter illustrates the proposed risk assessment process identified by the participants of the 2011 SETAC Workshop on Pesticide Risk Assessment for Pollinators. The potential risk to adult honey bees from spray applications is assessed through calculation of an HQ. The screening-level and refined risk assessment processes for soil or seed treatment-applied pesticides incorporate different degrees of ecological realism. Screening-level assessments are typically based on conservative assumptions regarding both exposure and effects.

An essential component of an ecological risk assessment is a prediction of exposure of the organisms being assessed. This chapter outlines exposure pathways for the different pesticide delivery methods, both nonsystemic and systemic, and discusses methods used to predict pesticide exposure to honey bees and non-Apis bees. It provides an outline of techniques employed to measure pesticide residues in relevant matrices and discusses higher tier field study designs that are used to refine bee exposure assessments for specific products. The chapter presents perspectives regarding pesticide application technologies that can be employed to mitigate bee exposure, as well as future research needs to further refine exposure assessments for this taxa. Workshop participants agreed that the most significant route of exposure to bees from foliar-applied pesticides is from both contact and oral exposure to contaminated pollen, nectar, and processed food.

This chapter provides an overview of existing toxicity tests and their strengths and weaknesses, and discusses proposed modifications to existing studies, or additional studies that could address limitations in the current battery of studies. In the European Union (EU), regulatory authorities may require a bee brood feeding test to assess potential hazard of a pesticide on honey bee larvae. The chapter reports toxicity testing with some species of adult non-Apis bees with some frequency. It discusses some of the methods that have been developed to measure the potential sublethal effects of pesticides on honey bees. Laboratory toxicity tests are currently available for evaluating the potential effects of chemicals on bees. Laboratory-based studies will likely continue to focus on individual test organisms; and, although laboratory-based toxicity testing has historically focused on mortality, tests are evolving to provide insight on sublethal effects such as impaired behavior.

This chapter provides an overview of what to consider when planning or assessing either a semi-field or field study for toxicity testing. Elements in the design of semi-field and field studies encompass the study's objectives, the test organism, a study site, methods, endpoints, sample design, quality assurance and quality control standards, and the statistical analysis of the data. A semi-field study is designed to measure exposure or effects and is performed on a crop that is grown outdoors in an enclosed test system with controlled or confined exposure. A field study is designed to measure exposure or effects and is performed on a crop that is grown outdoors with no enclosure. The chapter describes the semi-field and field study for Apis and Non-Apis Bees. Monitoring schemes, for example, the UK Wildlife Incident Investigation Scheme (WIIS), rely on incidents being reported to a central organization.

This paper is a guidance document for side-effect testing with plant protection products on non-target arthropods under semi-field and field conditions. The principles, methods, endpoints and interpretation of non-target arthropod semi-field and field trials which should be conducted for registration of plant protection products in the European Union are presented and discussed. The recommendations presented reflect the opinions of the experts from authority, academia, industry and consulting which participated at the IOBC (International Organisation of Biological Control), BART (Beneficial Arthropod Regulatory Testing) group and EPPO (European Plant Protection Organisation) Joint Initiative workshop held in Versailles (France) on the 25–26 October, 1999.

The EU Plant Protection Product Directive 91/414/EEC recommends the EPPO/CoE Arthropod Natural Enemies Risk Assessment Scheme for guidance on how to conduct risk assessments for terrestrial non-target arthropods. This scheme is currently in the process of being revised by EPPO/ CoE. A major change will be the recommendation for the generation and use of ’Dose Response’ toxicity data instead of limit test data. In addition, the revised EPPO/CoE Non-target Arthropods Risk Assessment Scheme will replace the current arbitrary 30% threshold trigger value applied to limit test data, with a Hazard Quotient (HQ; = Ratio Application Rate/LC50 on Glass)), comparable to the successful approach adopted in the EPPO/CoE ’Honeybee Risk Assessment Scheme’. However, in order for this new approach to be implemented under 91/414/EEC, an appropriate regulatory HQ trigger value needs to be derived. Such an HQ trigger value has been established by calculating HQ values for the 2 recommended sensitive indicator species (T pyri andAphidius) for a wide range of products and validating opposite robust semi-field/field data. This validation indicated that an HQ trigger value of ≥ 12 forT pyri and ≥ 8 forAphidius spp., should be used to trigger higher-tier risk assessment and/or higher-tier testing for non-target arthropods. As these trigger values were validated with realistic semi-field/ field data they apply for both lethal and sub-lethal effects as well as single and multiple application scenarios. Due to the worst case assumptions used in this HQ validation analysis, no further uncertainty factors need to be applied for in-crop risk assessment. Whilst a small amount of uncertainty exists regarding the comparative sensitivity ofT pyri andAphidius spp. for off-crop non-target arthropod guilds of arthropods, this is balanced by the fact that the off-crop exposure assessment used in the HQ derivation, is at least an order of magnitude higher than that realistically likely in the field. This HQ approach and trigger value is an appropriate and conservative tool for tier 1 risk assessment, which should reduce the number of false positive results leading to unnecessary higher-tier testing.

Petri dish experiments were conducted to study intraguild predation (IGP) between erigonid spiders (Erigone atra (Blackwall), Oedothorax apicatus (Blackwall), a carabid beetle (Pterostichus melanarius (Ill.) and lacewing, Chrysoperla carnea (Stephens) larvae. Erigonid spiders increased the mortality rates of lacewing larvae to different degrees, depending on the species and sex of spider concerned. The effect of spiders on lacewing larvae was highest (up to nearly 100% mortality) in the absence of alternative prey. In the presence of three or 20 aphids (Sitobion avenae Fab.) female erigonids increased the mortality rates of lacewing larvae compared to controls, but predation on lacewing larvae decreased in the presence of increasing numbers of aphids. Males of O. apicatus caused no significant increase in mortality rate of lacewing larvae in the presence of aphids. Lacewing larvae (L2-larvae and L3-larvae) did not kill erigonid spiders. IGP between the female erigonids E. atra and O. apicatus was not found. P. melanarius fed on lacewing larvae and on erigonid spiders, and E. atra was preferred over O. apicatus. The sex-specific and species-specific IGP rates of spiders on lacewing larvae and the great influence of alternative prey on IGP rate reveal a general problem when data resulting from one sexual stage or one species or one feeding regime are generalized to a whole arthropod group. Moreover, the results suggest that an increase of top predators, such as carabid beetles, which prey only to a limited extent on the pest species itself, may affect natural insect pest control by IGP.

The current rearing technique for Erigone atra (Blackwall) and Oedothorax apicatus (Blackwall) (Araneae, Erigonidae) was improved. To reduce time spent rearing on live fruit flies the spiders were kept on a culture of the Collembola species Lepidocyrtus lanuginosus (Gmelin) (Entomobryidae). Side-effects on spiders of two pyrethroid insecticides (fenvalerate and lambda-cyhalothrin) and one carbamate insecticide (pirimicarb) were tested. Sensitivity of adults of both sexes and juveniles to insecticides and their influence on the rate of emergence of spiderlings from cocoons were investigated using topical application, spraying or residual contact. LD50 values for adults ranged from 0.49 to 2.52 ng a.i./spider for lambda-cyhalothrin and from 5.75 to 98.20 ng a.i./spider for fenvalerate. Topical application also resulted in up to a week's delay of web-building. A moving laboratory spraying equipment was used to spray spiders with different insecticide dosages and water volumes. Pyrethroids sprayed onto adults in webs had stronger effects than pyrethroids sprayed onto sitting or walking spiders on the soil surface. Residual contamination caused higher mortality of spiders after contact with lambda-cyhalothrin than fenvalerate. In all tests, males were more susceptible to pyrethroids than females; this difference was related to body weight. Mortality rate was higher for E. atra than for O. apicatus. Both pyrethroids were also toxic to spiderlings. Lambda-cyhalothrin inhibited emergence of E. atra spiderlings from cocoons. Pirimicarb was harmless to both spider species.

To evaluate the effect of the indoxacarb 300 g kg -1 WG, Steward 30WDG™, on the honey bee (Apis mellifera L.) in apple orchards, a monitoring study was conducted in Dutch apple orchards in April/May 2004. Before apple flowering began, two honey bee colonies were placed in each orchard to investigate honey bee mortality. Each hive was provided with a Minister dead bee trap to collect dead honey bees. The numbers of dead bees found in these Minister dead traps were counted every 3-4 days for about 2 weeks before and after the period of the insecticide treatment. In nine flowering orchards no indoxacarb was applied during the flowering period, which served as control sites. In 30 flowering orchards indoxacarb was sprayed by the fruit growers according to local practice at 170-260 g formulated product ha -1 (51-78 g AI ha -1 ). In the control orchards the average mortality was 8 honey bees colony -1 day -1 . The average daily honey bee mortality before and after indoxacarb application was 8 and 10 honey bees colony -1 day -1 respectively. At one test site, indoxacarb was mixed with other plant protection products plus plant nutrients, and in this orchard a slight but biologically non-significant increase in acute honey bee mortality was recorded. It was concluded that the application of indoxacarb caused no effects on honey bee mortality, and that the number of dead honey bees counted in the Munster traps in the orchard treated with indoxacarb was comparable with those determined in control orchards.