Ants can influence ecological processes, such as the transfer of elements or radionuclides, in several ways. For example, they redistribute materials while foraging and maintaining their nests and have an important role in terrestrial food webs. Quantitative data of the transfer of elements into ants is needed, e.g., for developing improved radioecological models. In this study, samples of red wood ants (genus Formica), nest material, litter and soil were collected from a former uranium mining site in Eastern Finland. Concentrations of 33 elements were analyzed by Inductively Coupled Plasma-Mass Spectroscopy/Optical Emission Spectroscopy. Estimated element concentrations in spruce needles were used as a proxy for studying the transfer of elements into ants via aphids because spruces host the most important aphid farms in boreal forests. Empirically determined organism/medium concentration ratios (CRs) are commonly used in radioecological models. Ant/soil CRs were calculated and the validity of the fundamental assumption behind the of use of CRs (linear transfer) was evaluated. Elements that accumulated in ants in comparison to other compartments were cadmium, potassium, phosphorus, sulfur, and zinc. Ant uranium concentrations were low in comparison to soil, litter, or nest material but slightly elevated in comparison to spruce needles. Ant element concentrations were quite constant regardless of the soil concentrations. Non-linear transfer models could therefore describe the soil-to-ant transfer better than conventional CRs.

Veterinary antibiotics are widely used in livestock production and can be released to the environment via manure, affecting non-target organisms. Recent studies provide evidence that antibiotics can adversely affect both plants and insects but whether antibiotics in soil also affect trophic interactions is unknown.We tested whether antibiotics grown in sand as soil substitute with environmentally relevant concentrations of penicillin, sulfadiazine and tetracycline affect the survival of aphids feeding on plants (two crop and one non-crop plant species). Apera spica-venti, Brassica napus, and Triticum aestivum individuals were infested with aphids that were monitored over four weeks. We did not observe effects of penicillin or tetracycline on plants or aphids. However, sulfadiazine treatments reduced plant growth and increased mortality in the two tested grass species, but not in B. napus. Sulfadiazine subsequently decreased aphid density indirectly through reduced host plant biomass. We thus show that an antibiotic at realistic concentrations in a soil substitute can affect several trophic levels, i.e. plants and herbivores. This study contributes to the environmental risk assessment of veterinary antibiotics as it implies that their use potentially affects plant-insect interactions at environmentally relevant concentrations.

Although ozone is well-documented to reduce crop yields in the densely populated Indo-Gangetic Plain, there is little knowledge of its effects in other parts of south Asia. We surveyed crops close to the city of Peshawar, in north-west Pakistan, for visible injury, linking this to passive measurements of ozone concentrations. Foliar injury was found on potato, onion and cotton when mean monthly ozone concentrations exceeded 45 ppb. The symptoms on onion were reproduced in ozone fumigation experiments, which also showed that daytime ozone concentrations of 60 ppb significantly reduce the growth of a major Pakistani onion variety. Aphid infestation on spinach was also reduced at these elevated ozone concentrations. The ozone concentrations measured in April–May in Peshawar, and used in the fumigation experiment, are comparable to those that have been modelled to occur over many parts of south Asia, where ozone may be a significant threat to sensitive crops.

From 2014 to 2016, individuals of the principal non-target arthropod (NTA) species in a field of Bt maize expressing the Cry1Ac protein (Bt38) were compared to those in a control field of the corresponding non-transformed near isoline (Z58). For all 3 years, the population dynamics and biodiversity of NTAs were analyzed to determine if any differences might be attributable to the genetically modified (GM) maize being evaluated. The main NTAs in these fields were Aphidoidea, Pentatomidae,Araneae, and Coccinellidae. Temporal variation in NTA diversity across sample dates within a year showed no significant differences between the Bt maize and the non-Bt maize field in the total number of individuals of the dominant arthropod species per 25 plants, the Shannon index (H), Pielou index (J), Simpson index (D), and Bray-Curtis index. The cultivation of Bt corn failed to show any detrimental evidence on individuals, H, J, D, and Bray-Curtis index of NTAs, and these parameters were identical in Bt and non-Bt corn plots. These results provide further evidence of the lack of ecological impact of GM maize.

Apple orchards are heavily treated crops and some sprayed insecticides are recognized to have toxic effects on non-target arthropods. Earwigs are important natural enemies in pip-fruit orchards and contribute to the biological control of aphids. In addition, due to their ease of capture and identification, they are an interesting potential bioindicator of the possible detrimental effects of different orchard management strategies. In this study, we measured the energy reserves and some morphological traits of Forficula auricularia L. sampled in apple orchards under management strategies (organic versus integrated pest management (IPM)). We observed a significant decrease in mass (22 to 27%), inter-eye width (3%), and prothorax width (2 to 5%) in earwigs from IPM compared to organic orchards. Energy body reserves also confirmed these results with a significant decrease of 48% in glycogen and 25 to 42% in lipid content in earwigs from IPM compared to organic orchards. However, the protein content was approximately 70% higher in earwigs from IPM than in organic orchards. Earwigs sampled in IPM orchards may adapt to minimize the adverse toxic effects of pesticide treatments using a large number of strategies, which are reflected in changes to their energy reserves. These strategies could, in turn, influence the population dynamics of natural enemies and impair their role in the biological control of pests in apple orchards.

The increasing demand for lessening the chemical input in agricultural ecosystems requires an efficient combination of pesticides and biological controls. Thus, fully understanding the compatibility of pesticides and beneficial arthropod predators is helpful and essential. In this study, we evaluated the influence of nitenpyram on both larvae and adults of Coccinella septempunctata using exposure doses of 10, 25, 50, 100, and 150% of the maximum recommended field rate (MRFR) (3, 7.5, 15, 30, and 45 g a.i. ha⁻¹, respectively) and a blank control based on a preliminary acute 72-h toxicity experiment. In the long-term test, the LR₅₀ (application rate causing the mortality of 50% of the individuals) of nitenpyram for C. septempunctata decreased from 73.43 to 63.0 g a.i. ha⁻¹, while the HQ (hazard quotient) values remained below the threshold value of 2. Nitenpyram did not significantly influence the survival rate, fecundity, pupation, or adult emergence at 150% of the label rate (lowest LR₅₀ = 63.0 g a.i. ha⁻¹), and its demonstrated NOER (No Observed Effect application Rates) values are all above 45 g a.i. ha⁻¹. Likewise, the total developmental time and egg hatchability were not significantly affected at 100% of the label rate (NOER = 30 g a.i. ha⁻¹). The assessment of the total effect (E) suggested that nitenpyram could be classified as harmless to C. septempunctata below/at a dose of 30 g a.i. ha⁻¹. The lowest LR₅₀ and NOER values were both above the maximum recommended field application rate for nitenpyram (30 g a.i. ha⁻¹) for controlling aphids in China. All results indicated that the on-label use of nitenpyram is compatible with the natural enemy C. septempunctata in agricultural ecosystems.

The European earwig Forficula auricularia is an effective predator in apple orchards. It is therefore crucial to study whether insecticides affect this natural pest control agent. Predation activity, i.e., the number of aphids eaten in 24 h, was determined under laboratory conditions after exposure of fourth-instar nymphs and adult earwigs to widely used insecticides (acetamiprid, chlorpyrifos-ethyl, deltamethrin, and spinosad), which were applied at the normal application rates. Inhibition of acetylcholinesterase and carboxylesterase activities were also measured as indicators of pesticide exposure. Predation activity decreased significantly in nymphs exposed to spinosad (62 %) and chlorpyrifos-ethyl (98 %) compared with controls. A similar response was found for both esterase activities. Spinosad had a stronger effect on AChE (−33 %) whereas chlorpyrifos-ethyl affected CbE activity preferentially (−59 %). Spinosad (20 % of controls), acetamiprid (28 %), and chlorpyrifos-ethyl (66 %) also significantly decreased the predation behavior of adult male but not female (5 to 40 %) earwigs. Adult AChE and CbE activities were also significantly reduced (28 to 67 % of controls) in pesticide-exposed earwigs. Our results suggest that earwigs should be included in the environmental risk assessment framework for authorization of newly marketed plant protection products. Their predation behavior appears to be a sensitive and complementary biomarker.

Transgenic maize expressing the Cry1Ab and Cry2Ab protein simultaneously from Bacillus thuringiensis (Bt-maize) has been grown for farm-scale study to investigate its potential impact to non-target arthropod (NTA). The trials were conducted between Bt maize 2A-7 and its parental line (B73-329) in Beijing, China, over 3 years. Richness (C), Shannon index (H), Pielou index (J), Simpson index (D), and Bray-Curtis index were used to evaluate the population dynamics and biodiversity of the dominant arthropods from per 50 plants in crop field. The mainly abundant groups were Aphidoidea, Araneae, Coccinellidae, Anthocoridae, and Thripidae which represented about 90% of the total number of NTA. Although the abundance of NTA varied from year to year, there is no significant difference between Bt maize and non-Bt maize field. Fluctuations were found at individual sample dates, but the trend of these descriptors remained consistent. Further analysis showed the biodiversity indexes of the dominant arthropods C, H, J, D, and Bray-Curtis dissimilarity between Bt maize producing Cry1Ab and Cry2Ab toxin simultaneously and its parental line had no significant difference except for some sampling dates. These results suggested that Bt maize is compatible with the NTAs and provides further evidence of the ecological impact of genetically modified maize.

Studying the toxic risk of pesticide exposure to ladybird beetles is important from an agronomical and ecological perspective since larval and adult ladybirds are dominant predators of herbivorous pest insects (e.g., aphids) in various crops in China. This article mainly deals with the long-term effects of a single application of the insect growth regulator hexaflumuron on Coccinella septempunctata. A 72-h and a 33-day toxicity test with hexaflumuron (single application) were performed, starting with the second instar larvae of C. septempunctata. Exposure doses in the long-term experiment were based on the estimated 72-h acute LR₅₀(application rate causing 50 % mortality) value of 304 g active ingredient (a.i.) ha⁻¹for second instar larvae of C. septempunctata. The long-term test used five hexaflumuron doses as treatment levels (1/50, 1/100, 1/200, 1/400, and 1/800 of the 72-h acute LR₅₀), as well as a solvent control and blank control treatment. The measurement endpoints used to calculate no observed effect application rates (NOERs) included development time, hatching, pupation, adult emergence, survival, and number of eggs produced. Analyzing the experimental data with one-way analysis of variance showed that the single hexaflumuron application had significant effects on C. septempunctata endpoints in the 33-day test, including effects on development duration (NOER 1.52 g a.i. ha⁻¹), hatching (NOER 3.04 g a.i. ha⁻¹), pupation (NOER 3.04 g a.i. ha⁻¹), and survival (NOER 1.52 g a.i. ha⁻¹). These NOERs are lower than the reported maximum field application rate of hexaflumuron (135 g a.i. ha⁻¹) in cotton cultivation, suggesting potential risks to beneficial arthropods.