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Pesticides can pose environmental risks, and a common neonicotinoid pesticide, thiamethoxam, decreases homing success in honey bees. Neonicotinoids can alter bee navigation, but we present the first evidence that neonicotinoid exposure alone can impair the physical ability of bees to fly. We tested the effects of acute or chronic exposure to thiamethoxam on the flight ability of foragers in flight mills. Within 1 h of consuming a single sublethal dose (1.34 ng/bee), foragers showed excitation and significantly increased flight duration (+78%) and distance (+72%). Chronic exposure significantly decreased flight duration (-54%), distance (-56%), and average velocity (-7%) after either one or two days of continuous exposure that resulted in bees ingesting field-relevant thiamethoxam doses of 1.96-2.90 ng/bee/day. These results provide the first demonstration that acute or chronic exposure to a neonicotinoid alone can significantly alter bee flight. Such exposure may impair foraging and homing, which are vital to normal colony function and ecosystem services.

Simple Summary: Botanical insecticides and soaps are frequently considered environmentally friendly and compatible with the biological control of pests because of their purported higher selectivity towards beneficial insects when compared with synthetic insecticides. These claims are, however, only partially backed up by the scientific literature, thus justifying a case-by-case evaluation of botanical insecticides. Here, we tested the efficacy of five botanical insecticides and soaps belonging to different categories (pyrethrins, essential oils, crude plant extracts and insecticidal soaps) on the important aphid pest Myzus persicae (Sulzer) and their selectivity towards two of its biological control agents, the ladybird beetle Propylea quatuordecimpunctata (L.) and the parasitoid Aphidius colemani (Dalman). The pyrethrin-based product was the most effective against aphids but more detrimental to ladybird beetle larvae when compared to the alternatives. Some detrimental effects on ladybird beetles were also caused by white thyme essential oil, sweet orange essential oil and Marseille soap. Additionally, although pyrethrins have a broader spectrum of insecticidal activity compared to most botanical insecticides, they had no significant adverse effect on adult ladybird beetles and parasitoids within aphid mummies, similar to most of the other tested natural products. Botanical insecticides and soaps are frequently proposed as environmentally safer alternatives to synthetic insecticides. However, the efficacy and selectivity of these products are often only partially supported by empirical evidence. Here, we tested the effectiveness of five botanical insecticides, belonging to different categories, on the green peach aphid Myzus persicae (Sulzer) and their selectivity towards two natural enemies, the ladybird beetle Propylea quatuordecimpunctata (L.) and the parasitoid Aphidius colemani (Dalman). White thyme essential oil (EO), sweet orange EO, crude garlic extract and Marseille soap were tested and compared with a pyrethrin-based commercial product. Both direct spray assays and residual contact assays on treated cabbage leaf disks were carried out. The tested products had low efficacy against aphids when compared to pyrethrins but were in general less detrimental to ladybird beetle larvae, meaning that if applied against other pests, they have a lower chance of harming this agent of aphid biocontrol. Some of the products (soap, orange EO) did, however, show direct exposure toxicity toward ladybird larvae, and thyme EO had extensive phytotoxic effects on cabbage leaves, possibly indirectly leading to higher mortality in ladybird adults. These results underline the necessity for case-by-case evaluations of botanical insecticides. [ABSTRACT FROM AUTHOR]

Milesia crabroniformis (F.) is a large hornet-mimic hoverfly considered relatively rare in Italy. During visual samplings along a transect carried out in Castiglione dei Pepoli (Bologna, Italy), with the aim of monitoring changes in hoverfly communities over sixty years, the authors observed and counted at least one hundred specimens of this hornet-mimic hoverfly while foraging on Sambucus ebulus L. This note aims to document this very infrequent behaviour of M. crabroniformis to contribute to the understanding of this phenomenon. [ABSTRACT FROM AUTHOR]

Simple Summary: Insect pollinators play an essential service in agricultural systems, but are commonly exposed to pesticides. Although pollinators are present in several insect orders, above all dipterans, information on pesticide sensitivity is mostly restricted to bees. We assessed the sensitivity of two hoverflies (Sphaerophoria rueppellii, Eristalinus aeneus) and one tachinid fly (Exorista larvarum) to a neonicotinoid insecticide (Confidor®, imidacloprid). We adapted the standardized methodology of acute contact exposure in honey bees to build dose–response curves and calculate median lethal doses (LD50) for the three species. S. rueppelli was the most sensitive, E. aeneus the least. Results were compared with those available in the literature for other pollinator species using a species sensitivity distribution (SSD) approach: as a result, the 95th percentile of pollinator species would be protected by a safety factor of 100 times the Apis mellifera endpoint. Dipterans were less sensitive to imidacloprid than most bee species. We measured the number of eggs laid following exposure to different insecticide doses and assessed the potential trade-off between oviposition and survival through the sublethal sensitivity index (SSI). Pesticide exposure had a significant effect on fecundity, and SSI values indicated that oviposition is a sensitive endpoint for the three dipteran species tested. Insects play an essential role as pollinators of wild flowers and crops. At the same time, pollinators in agricultural environments are commonly exposed to pesticides, compromising their survival and the provision of pollination services. Although pollinators include a wide range of species from several insect orders, information on pesticide sensitivity is mostly restricted to bees. In addition, the disparity of methodological procedures used for different insect groups hinders the comparison of toxicity data between bees and other pollinators. Dipterans are a highly diverse insect order that includes some important pollinators. Therefore, in this study, we assessed the sensitivity of two hoverflies (Sphaerophoria rueppellii, Eristalinus aeneus) and one tachinid fly (Exorista larvarum) to a neonicotinoid insecticide (Confidor®, imidacloprid) following a comparative approach. We adapted the standardized methodology of acute contact exposure in honey bees to build dose–response curves and calculate median lethal doses (LD50) for the three species. The methodology consisted in applying 1 µL of the test solution on the thorax of each insect. Sphaerophoria rueppelli was the most sensitive species (LD50 = 10.23 ng/insect), and E. aeneus (LD50 = 18,176 ng/insect) the least. We then compared our results with those available in the literature for other pollinator species using species sensitivity distribution (SSD). Based on the SSD curve, the 95th percentile of pollinator species would be protected by a safety factor of 100 times the Apis mellifera endpoint. Overall, dipterans were less sensitive to imidacloprid than most bee species. As opposed to most bee species, oviposition and fecundity of many dipteran species can be reliably assessed in the laboratory. We measured the number of eggs laid following exposure to different insecticide doses and assessed the potential trade-off between oviposition and survival through the sublethal sensitivity index (SSI). Exposure to imidacloprid had a significant effect on fecundity, and SSI values indicated that oviposition is a sensitive endpoint for the three dipteran species tested. Future studies should integrate this information related to population dynamics in simulation models for environmental risk assessment. [ABSTRACT FROM AUTHOR]

Recent studies have opened the way for using elicitor‐induced resistance in plants as a method to control arthropod pests. In this study, 1,3‐β‐glucan laminarin, an elicitor of disease resistance in plants, was tested on the green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), on peach [Prunus persica (L.) Batsch, Rosaceae] plantlets and evaluated its effects on short‐term mortality and population growth. Laminarin exposure did not affect aphid survival in the short term; however, laminarin‐treated peach plants sustained fewer nymphs and adults in comparison with the control. Aphid populations on plants treated with laminarin declined significantly over the sampling period compared to the control. Moreover, the demographic parameters net reproductive rate (R0), finite rate of increase (λ), and intrinsic rate of increase (rm), all showed decreasing trends in aphid populations reared on laminarin‐treated plants. The decline in aphid populations exposed to laminarin seemed to mainly be linked to reduced adult survival, slower nymph development, and lower nymph survival and only marginally to changes in reproduction outcome. Changes in gene expression causing the final production of defence chemicals by peach plants may contribute to explaining the results. However, potential direct effects of laminarin on M. persicae feeding activity and probing behaviour cannot be ruled out. This study provides evidence that, although laminarin did not display insecticidal activity in the short term, this elicitor caused sublethal effects, significantly reducing aphid populations. [ABSTRACT FROM AUTHOR]

In this paper we assessed, under laboratory conditions, the toxicity of an active substance on solitary bee larvae of Osmia cornuta (Hymenoptera: Megachilidae). A field-realistic dose of the systemic insecticide spirotetramat was applied to the mass provisions. The insecticide’s effects on several life-cycle parameters were studied in males and females. Our results showed a significantly shorter post-emergence longevity in bees exposed to spirotetramat during the larval stage, compared to the control. The observed reduction in longevity was 18 and 15%, respectively, in males and females. Mortality rate and other biological traits (larval and spinning duration, emergence time, food/body conversion rate) did not show significant differences between the two treatments. The method described in this study can be used to test the effects of toxic substances (i.e. agrochemicals) on bees. Moreover, it can constitute a basis for the development of a standardised protocol in the first tier of the Environmental Risk Assessment for solitary bees.

The predatory mites of the Phytoseiidae family are crucial biological control agents widely utilized in biological pest management targeting phytophagous mites and insects. Key factors in these control strategies are that phytoseiids must be able to find their main target prey and to maintain high populations and efficacy. To reduce expenses and time-consuming production methods of mass rearing of phytoseiids, pollen and other factitious (i.e. non-natural/nontarget) hosts need to be present as an alternative food for predatory mite populations. The mass-rearing possibilities of these predators on alternative food sources, such as astigmatid mites (i.e. house and stored mites) and pollen, must be evaluated not only by the cost of rearing settings but on the basis of their efficiency maintenance in killing prey. The pest kill rate (k m ) is the average daily lifetime killing of the pest by the natural enemy under consideration and can represent a useful indicator for phytoseiids efficacy to rank them as BCAs on the basis of their effective killing/predation on target prey. In this study, we evidenced that 2 astigmatid mites, Glycyphagus domesticus (De Geer) and Lepidoglyphus destructor (Schrank), and Quercus ilex L. pollen can be successfully adopted as substitute food sources for mass rearing of the phytoseiid Neoseiulus californicus (MgGregor); then, we determined that these populations of BCAs maintained a consistent k m at new/first impact on the main target pest, Tetranychus urticae Koch. [ABSTRACT FROM AUTHOR]