This study describes the development of acetylcholinesterase (AChE), carboxylesterases (CaE1, CaE2, CaE3), glutathion-S-transferase (GST), alkaline phosphatase (ALP) and catalase (CAT) as enzyme biomarkers of exposure to xenobiotics such as thiamethoxam in the honey bee Apis mellifera. Extraction efficiency, stability under freezing and biological variability were studied. The extraction procedure achieved good recovery rates in one extraction step and ranged from 65 percent (AChE) to 97.3 percent (GST). Most of the enzymes were stable at -20°C, except ALP that displayed a slight but progressive decrease in its activity. Modifications of enzyme activities were considered after exposure to thiamethoxam at the lethal dose 50 percent (LD(50), 51.16 ng bee(-1)) and two sublethal doses, LD(50)/10 (5.12 ng bee(-1)) and LD(50)/20 (2.56 ng bee(-1)). The biomarker responses revealed that, even at the lowest dose used, exposure to thiamethoxam elicited sublethal effects and modified the activity of CaEs, GST, CAT and ALP. Different patterns of biomarker responses were observed: no response for AChE, an increase for GST and CAT, and differential effects for CaEs isoforms with a decrease in CaE1 and CaE3 and an increase in CaE2. ALP and CaE3 displayed contrasting variations but only at 2.56 ng bee(-1). We consider that this profile of biomarker variation could represent a useful fingerprint to characterise exposure to thiamethoxam in the honey bee A. mellifera. This battery of honey bee biomarkers might be a promising option to biomonitor the health of aerial and terrestrial ecosystems and to generate valuable information on the modes of action of pesticides.

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The present study was intended to evaluate the responses of enzymes in the honeybee Apis mellifera after exposure to deltamethrin, fipronil, and spinosad and their use as biomarkers. After determination of the median lethal doses (LD50), honeybees were exposed at doses of 5.07 ng/bee and 2.53 ng/bee for deltamethrin, 0.58 ng/bee and 0.29 ng/bee for fipronil, and 4.71 ng/bee and 2.36 ng/bee for spinosad (equivalent to 1/10th [LD50/10] and 1/20th [LD50/20] of the LD50, respectively). The responses of acetylcholinesterase (AChE), carboxylesterases (CaEs-1-3), glutathione-S-transferase (GST), catalase (CAT), and alkaline phosphatase (ALP) were assessed. The results showed that deltamethrin, fipronil, and spinosad modulated these biomarkers differentially. For the enzyme involved in the defense against oxidative stress, fipronil and spinosad induced CAT activity. For the remaining enzymes, 3 response profiles were identified. First, exposure to deltamethrin induced slight effects and modulated only CaE-1 and CaE-2, with opposite effects. Second, spinosad exhibited an induction profile for most of the biomarkers, except AChE. Third, fipronil did not modulate AChE, CaE-2, or GST, increased CAT and CaE-1, and decreased ALP. Thus, this set of honeybee biomarkers appears to be a promising tool to evaluate environmental and honeybee health, and it could generate fingerprints to characterize exposures to pesticides.

Pesticides are considered the first line of defense for the control of pests and diseases. At least in the short and medium term, the use of pesticides will remain an important strategy for pest management, allowing growers to produce crops of sufficient quality at low costs. A broad approach known as Integrated Pest Management (IPM) combines several different pest-control strategies, among which the combination of chemical and biological control stands out. It requires pesticides that achieve optimal control of target pests with minimal impact on the activity of biological control agents. Because of the dynamics of pest infestations, IPM routines are continuously adjusted by growers, requiring comprehensive information about pesticide effects on natural enemies. However, this information is not always available and often contradictory, which constrains the design of field recommendations. In this review, we focused on the importance of selective pesticides in IPM programs, and the effects of chemical pesticides on parasitoids, predators, and entomopathogenic fungi. We provided a detailed discussion of the challenges and constraints for research on pesticide effects on natural enemies, as well as for the resulting field recommendations.

The development of new strategies to control pest insects is required, in combination with conventional pesticides or replacing them. Essential oils produced from botanical extracts used in management programs should be effective against pests and selective to natural enemies. Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is one of the most destructive pests of solanaceous crops in the world, and a possible management strategy consists of releases of the predator Nesidiocoris tenuis (Hemiptera: Miridae), along with botanical applications. The objective of this study was to evaluate the effects of Prev-am ® oil on T. absoluta offspring, either with or without the predator N. tenuis, as well as the oil's effects on N. tenuis predatory behavior and longevity. The oil's effects were compared with distilled water (control) and a synthetic pesticide (lambdacyhalothrin). The response of populations to lambda-cyhalothrin was similar to that with Prev-am ® , compared to the control, showing that N. tenuis had higher capacity to reduce T. absoluta populations. The survival analysis of predators exposed to Prev-am ® indicates that none of the concentrations differed significantly from the control. In addition, the canonical variate analysis indicated significant overall differences in the predator behavior submitted to different treatments, suggesting that synthetic pesticide treatment affected predator behavior when compared to control and Prev-am ® . Reduction in predatory voracity of N. tenuis adults exposed to leaves treated with pesticide and biopesticide was significant compared to the control treatment. The results obtained could improve IPM programs against T. absoluta through the Prev-am ® applications and N. tenuis releases.Keywords Natural product · Predatory mirid · South American tomato pinworm · Ecotoxicology · Biological control Key message• New strategies based on the use of natural enemies and biopesticides to control Tuta absoluta are desirable for integrated pest management (IPM). • The combination of Nesidiocoris tenuis with Prev-am ® (at half of the recommended concentration) showed enhanced efficacy against T. absoluta. • Presence of N. tenuis significantly reduced T. absoluta population growth. • Lambda-cyhalothrin and Prev-am ® could disturb behavioral response of N. tenuis.