Francisco Sánchez-Bayo

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• PhD
• Honorary Associate at The University of Sydney

Systemic insecticides were introduced in the 1950s, but only recently have become the major insecticides applied in agriculture for plant and animal protection. The selective toxicity of fipronil and neonicotinoids toward insects and other arthropods contrasts with the broad-spectrum toxicity of former insecticides, making them safer for fish and v...

Recent years have witnessed heightened scrutiny of the non-target sublethal effects of pesticides on behavioural and physiological traits of insects. Traditionally, attention has focused on investigating pesticides' primary modes of action, often overlooking the potential secondary mechanisms. This review brings forth the nuanced impacts of subleth...

Neonicotinoid insecticides, the most widely used category of insecticides for 20 years, have been detected in various human tissues including blood, cerebrospinal fluid, urine, and hair. We collected spot urine from 99 volunteers in three islands of the Philippines, and compared their neonicotinoid concentrations with those obtained in paired hair...

Systemic insecticides are one of the causes of Odonata declines in paddy fields. Since rising temperatures associated with global warming can contribute to strengthen pesticide toxicity, insecticide exposures under increasing temperatures may accelerate the decline of Odonata species in the future. However, the combined effects of multiple stressor...

Rapid climate warming has boosted biological invasions and the distribution or expansion polewards of many species: this can cause serious impacts on local ecosystems within the invaded areas. Subsequently, native species may be exposed to threats of both interspecific competition with invaders and temperature rises. However, effects of warming on...

Neonicotinoid insecticides, the most widely used category of insecticides for 20 years and candidate risk of neurodevelopment, have been detected in human urine and in hair. If the former reflecting dietary contamination over short periods and the latter total exposure over longer periods is not known. We quantified and compared the concentrations...

Pesticides released to the environment can indirectly affect target and non-target species in ways that are often contrary to their intended use. Such indirect effects are mediated through direct impacts on other species or the physical environment and depend on ecological mechanisms and species interactions. Typical mechanisms are the release of h...

With the exponential number of published data on neonicotinoids and fipronil during the last decade, an updated review of literature has been conducted in three parts. The present part focuses on gaps of knowledge that have been addressed after publication of the Worldwide Integrated Assessment (WIA) on systemic insecticides in 2015. More specifica...

New information on the lethal and sublethal effects of neonicotinoids and fipronil on organisms is presented in this review, complementing the previous Worldwide Integrated Assessment (WIA) in 2015. The high toxicity of these systemic insecticides to invertebrates has been confirmed and expanded to include more species and compounds. Most of the re...

Over-reliance on pesticides for pest control is inflicting serious damage to the environmental services that underpin agricultural productivity. The widespread use of systemic insecticides, neonicotinoids, and the phenylpyrazole fipronil in particular is assessed here in terms of their actual use in pest management, effects on crop yields, and the...

Synthetic pesticides such as neonicotinoids are commonly used to treat crops in tropical regions, where data on environmental and human contamination are patchy and make it difficult to assess to what extent pesticides may harm human health, especially in less developed countries. To assess the degree of environmental and human contamination with n...

This is the Editorial introducing: https://link.springer.com/article/10.1007/s11356-017-0394-3 and https://link.springer.com/article/10.1007/s11356-017-0341-3 and https://link.springer.com/article/10.1007/s11356-017-1052-5 and https://link.springer.com/article/10.1007/s11356-020-09279-x

The Anthropocene is characterised by pervasive human‐inflicted impacts on a broad range of biota, including insects. In 2019, we reviewed scientific literature quantifying the prevalence and magnitude of insect declines in recent time. Here, drawing upon 40 additional long‐term studies, we add evidence that is consistent with our earlier review and...

Food can be health-giving. A global transition towards plant-based diets may equally help curb carbon emissions, slow land-system change and conserve finite resources. Yet, projected benefits of such 'planetary health' diets imperfectly capture the environmental or societal health outcomes tied to food production. Here, we examine pesticide-related...

Our mechanistic understanding of the toxicity of chemicals that target biochemical and/or physiological pathways, such as pesticides and medical drugs is that they do so by binding to specific molecules. The nature of the latter molecules (e.g., enzymes, receptors, DNA, proteins, etc.) and the strength of the binding to such chemicals elicit a toxi...

Leonard et al. (Science 367, 573-576, 2020) presented an interesting approach to limit the impact of pathogens on honeybees by stimulating immunity via engineered symbionts. The urgency to safeguard pollinator services is undoubted. Massive declines in bees, insects in general, pose major concerns for ecosystem stability and food production. Howev...

Numerosos estudios han advertido de que los insectos están desapareciendo a un ritmo mayor que otros grupos de animales. Algunos trabajos recientes, realizados por separado en Alemania, Puerto Rico e Inglaterra, han apuntado a una pérdida de la biomasa de insectos de entre el 70 y el 90 por ciento desde los años 80 del siglo pasado hasta ahora, lo...

Nearly 2.5 billion smallholders cultivate the world's arable land, strategically positioned to tackle multiple Anthropocene challenges. When consciously adopting ecologically-based pest management practices, they can improve resource use efficiency, slow biodiversity loss, curtail environmental pollution and safeguard human health. Yet, the effecti...

A summary of pesticide-related research carried out from 2001 to 2012 in channels, drains, creeks, lakes, rivers, and channel outfall in natural waterways in Goulburn Murray Water (GMW) Waterways in North Victoria, Australia (G-MW region covers 68,000 square kilometres). It includes i. pesticide usage in the six irrigation areas; ii. pesticide risk...

Indirect effects of agrochemicals on organisms via biotic interactions are less studied than direct chemical toxicity despite their potential relevance in agricultural landscapes. In particular, the role of species traits in characterizing indirect effects of pesticides has been largely overlooked. Moreover, it is still unclear whether such indirec...

Usage of neonicotinoids is common in all agricultural regions of the world but data on environmental contamination in tropical regions is scarce. We conducted a survey of five neonicotinoids in soil, water and sediment samples along gradients from crops fields to protected lowland tropical forest, mangroves and wetlands in northern Belize, a region...

Biodiversity of insects is threatened worldwide. Here, we present a comprehensive review of 73 historical reports of insect declines from across the globe, and systematically assess the underlying drivers. Our work reveals dramatic rates of decline that may lead to the extinction of 40% of the world's insect species over the next few decades. In te...

There is a growing concern that pollinators are in decline, potentially threatening biodiversity and sustainable food production on a global scale. In general, there is consensus on the multifactorial origin of this problem, and pesticides are regarded as one of the factors involved. Pollinators can be exposed to pesticides through different routes...

On 28 April 2018 the European Parliament voted for a complete and permanent ban on all outdoor uses of the three most commonly used neonicotinoid pesticides. With the partial exception of the state of Ontario, Canada, governments elsewhere have failed to take action. Below is a letter, signed by 232 scientists from around the world, urgently callin...

The Argentine ant, Linepithema humile (Mayr; Hymenoptera: Formicidae), is one of the world's most hazardous invasive species, and thus its eradication from Japan is important. Physical and chemical controls can be expensive and cause strong adverse effects on local terrestrial ecosystems regardless of their high efficacy. Here, presence/absence of...

Systemic insecticides were introduced in the 1950s, but only recently have become the major insecticides applied in agriculture for plant and animal protection. The selective toxicity of fipronil and neonicotinoids toward insects and other arthropods contrasts with the broad-spectrum toxicity of former insecticides, making them safer for fish and v...

Contamination of corn, peanuts, milk and dairy products with aflatoxins is a worldwide problem, particularly in subtropical regions where the climatic conditions are ideal for the growth of Aspergillus flavus, the fungi that produces these toxins. Developing countries have major difficulties in marketing these products abroad due to the stringent i...

A previous study claimed a differential behavioural resilience between spring or summer honey bees (Apis mellifera) and bumble bees (Bombus terrestris) after exposure to syrup contaminated with 125 µg L−1 imidacloprid for 8 days. The authors of that study based their assertion on the lack of body residues and toxic effects in honey bees, whereas bu...

The widespread use of chemicals for the control of pests, weeds and diseases in agriculture has produced a variety of effects on organisms and ecosystems. This chapter raises awareness of the negative consequences of using agricultural pesticides to the environment at large. After describing how pesticides are applied in agriculture, their ecologic...

The widespread contamination of a significant proportion of the planet’s land and water with pesticides is undeniable. While this takes place, innumerable species of animals associated with agricultural landscapes are declining at rates that may put them on the brink to extinction in the span of a lifetime. It is evident, therefore, that our curren...

The widespread use of systemic neonicotinoid insecticides in agriculture results first in contamination of the soil of the treated crops, and secondly in the transfer of residues to the aquatic environment. The high toxicity of these insecticides to aquatic insects and other arthropods has been recognized, but there is little awareness of the impac...

This chapter focuses on the detrimental effects that pesticides have on managed honey bee colonies and their productivity. We examine first the routes of exposure of bees to agrochemicals used for crop protection and their application to crops, fate and contami‐ nation of water and plants around the fields. Most of the time, the exposure of bees to...

Two dose response models have traditionally been used in risk assessment. Most regulatory agencies assume that there is no safe level of exposure to carcinogens but that a threshold, or ―safe‖ exposure level exists for non-carcinogens. However, recent discoveries have cast serious doubt on the validity of this concept. Dose – response relationships...

This chapter provides insights into the difficulties and challenges of performing risk evaluations of agrochemicals. It is a critical review of the current methodologies used in ecological risk assessment of these chemicals, not their risks to humans. After an introduction to the topic, the current framework for ecological risk assessment is outlin...

Fipronil is one of the most effective insecticides to control the invasive ant Linepithema humile, but its effectiveness has been assessed without considering the genetic differences among L. humile supercolonies. We hypothesized that the susceptibility of the ant to fipronil might differ among supercolonies. If so, dosage and concentration of fipr...

Chronic exposure to widely used insecticides kills bees and many other invertebrates

Imidacloprid, one of the most commonly used insecticides, is highly toxic to bees and other beneficial insects. The regulatory challenge to determine safe levels of residual pesticides can benefit from information about the time-dependent toxicity of this chemical. Using published toxicity data for imidacloprid for several insect species, we constr...

Bees are essential pollinators of many plants in natural ecosystems and agricultural crops alike. In recent years the decline and disappearance of bee species in the wild and the collapse of honey bee colonies have concerned ecologists and apiculturalists, who search for causes and solutions to this problem. Whilst biological factors such as viral...

Increasing and widespread use of neonicotinoid insecticides all over the world, together with their environmental persistence mean that surface and ground waters need to be monitored regularly for their residues. However, current multi-residue analytical methods for waters are inadequate for trace residue analysis of these compounds, while passive...

The effects of two successive annual treatments of imidacloprid and fipronil on dragonfly nymph communities, which are one of the best-known bioindicators in Japanese agroecosystems, were monitored in experimental paddies. The abundance of dragonfly nymphs was lower in both insecticides-treated fields than it was in the controls, particu- larly fol...

Outbreaks of infectious diseases in honey bees, fish, amphibians, bats and birds in the past two decades have coincided with the increasing use of systemic insecticides, notably the neonicotinoids and fipronil. A link between insecticides and such diseases is hypothesised. Firstly, the disease outbreaks started in countries and regions where system...

A passive sampler device suitable for monitoring of residues of the hydrophilic ionic herbicide amitrole in irrigation waterways was developed. Uptake of amitrole on styrenedivinylbenzene-reverse phase sulfonated Empore™ disks was linear and proportional to its water concentration over the range of 1-10 μg/L with a sampling rate of 23.1 mL/day unde...

The acute toxicity (48-hr) of old (imidacloprid) and new (clothianidin) neonicotinoid insecticides to five cladoceran species and species sensitivity distribution (SSD) for cladocerans and other aquatic organisms to these insecticides are compared here. The sensitivities to both insecticides were in the following descending order: Ceriodaphnia>Daph...

Average depth of snow in the mountains of south eastern Australia is decreasing at a rate of 0.48 cm a-1, while the duration of the snowpack has been shortened by 18.5 days since 1954 (-3 days per decade). The major factors responsible for these declines are an increasing temperature trend of 0.36 oC per decade, and a reduction in winter precipitat...

This review has brought some light on the direct, sublethal and indirect effects that systemic insecticides have on species populations and ecosystems. Some long-term impacts have been known for some time (e.g. carbofuran, phorate), but it is the rapid increase in the usage of neonicotinoids and other systemic products that poses a new challenge to...

Assessment of ecological impacts of toxicants relies currently on extrapolation of effects observed at organismal or population levels. The uncertainty inherent to such extrapolations, together with the impossibility of predicting ecological effects of chemical mixtures, can only be resolved by adopting approaches that consider toxicological endpoi...

Differences in susceptibility of five cladocerans to the neonicotinoid imidacloprid and the phenyl-pyrazole fipronil, which have been dominantly used in rice fields of Japan in recent years, were examined based on short-term (48-h), semi-static acute immobilization exposure tests. Additionally, we compared the species sensitivity distribution (SSD)...

The environmental risks of pesticides are typically determined by laboratory single-species tests based on OECD test guidelines, even if biodiversity should also be taken into consideration. To evaluate how realistic these assessments are, ecological changes caused by the systemic insecticides imidacloprid and fipronil, which have different physico...

The mode of action of insecticides is responsible for their higher or lower toxicity to non-target organisms. However, the large variations in susceptibility among different animal taxa indicate that certain biochemical traits particular to a group of organisms are responsible for a specific level of sensitivity. A review of toxicity data to non-ta...

Since the mid-1960s, environmental toxicology focussed on the effects of bioaccumulation of organochlorine insecticides in organisms, and their consequences for populations of species in the wild. Prompted by the release of Silent Spring [1], scientists sifted focus to the ecological effects of pesticides, thus expanding the narrow field of pestici...

A comparison of environmental risks of pesticides between tropical and nontropical regions has been performed, using data from the literature and modeling outputs based on the physicochemical properties of the compounds. With a few exceptions, the level of risk of exposure for most pesticides in tropical agriculture is similar to that in other clim...

Modern living standards depend largely on the production and usage of thousands of chemicals, many of which are toxic and synthetically produced. These substances are discharged into the air, soil, water bodies and the sea through a variety of ways, becoming pollutants of our environment. The investigation of their fate and impacts they have on eco...

Ecological Impacts of Toxic Chemicals presents a comprehensive, yet readable account of the known disturbances caused by all kinds of toxic chemicals on both aquatic and terrestrial ecosystems. Topics cover the sources of toxicants, their fate and distribution through the planet, their impacts on specific ecosystems, and their remediation by natura...

Pesticides are toxic chemicals used to control pests, weeds and pathogens. Three quarters of all pesticides are employed in agricultural production, particularly in developed countries, in an effort to mitigate crop damage endured by intensive agriculture. However, after more than 60 years of worldwide usage, their side-effects on terrestrial ecosy...

The known ecological impacts of insecticides on terrestrial and aquatic ecosystems are reviewed in this chapter. Awareness of the impacts that insecticides are having in our world may help introduce management practices that aim at reducing and mitigating those impacts. We must accept that pest control and disease eradication are complex issues tha...

The herbicides amitrole and glyphosate, and its metabolite aminomethyl-phosphonic acid (AMPA), in water samples have been directly analysed by high-performance liquid chromatography using an electrochemical (EC) detector. Limits of detection of 0.3 microg mL(-1) for glyphosate, 0.05 microg mL(-1) for AMPA and 0.03 microg mL(-1) for amitrole were co...

The influence of various diets on the survival, fecundity, and the polyunsaturated fatty acid (PUFA) composition of the benthic estuarine amphipod Melita plumulosa (Zeidler) in laboratory cultures were determined. Apart from a natural silty sediment, six commercial food supplements were examined: an omega-6 PUFA enriched Spirulina-based dry powder,...

The ability to predict the effects of toxicants in organisms with reasonable accuracy depends to a great extent on the toxico-kinetic models used to describe such effects. Toxic effects of organic chemicals and heavy metals have been described adequately using a hyperbolic model that considers the concentration of the toxicant and the time of expos...

In the Coleambally irrigation area (NSW, Australia), the occurrence of four tadpole and frog species in rice bays on farms growing either rice only or both rice and corn was studied over two seasons. In addition to analysis of species occurrence, both gonadal histology and assessment of Batrachochytrium dendrobatidis infection rates were performed....

The basis of ecotoxicology lies currently in the dose-response of organisms to toxicants, as typically described by probit and logistic models. While recognising its merits, standard endpoints ignore the process of toxicity with time, and consequently our ability to predict direct toxic effects in environmental risk assessments is seriously curtail...

Selection of agrochemicals that may control pest outbreaks while ensuring smaller impacts on the environment is important for the success of IPM. Currently, regulators evaluate risks from chemicals following a tiered system which relies heavily on the quotient method. To test the validity of two current models used for risk assessment, impacts of t...

Agrochemicals will remain essential for economic production of the bulk of the world’s food and fibre. However, their continued acceptance as agents for the control of pests has required a remarkable evolution in applied chemistry. To guarantee increasing environmental safety, an ongoing process of rational human action is needed, based on chemical...

To elucidate the ecological impacts of imidacloprid [1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine] on vegetable crops and their surrounding areas, arthropods on eggplant patches treated with this insecticide were monitored throughout two cultivation seasons, spring and autumn, and the results compared with those of control crops....

Ecological changes caused by the insecticide imidacloprid and a pollutant from antidandruff shampoos (zinc pyrithione) were monitored in experimental paddies throughout a cultivation period. A total of 88 species were observed, with 54 of them aquatic. Plankton, nekton, benthic, and terrestrial communities from imidacloprid fields had significantly...

The acute toxicity of imidacloprid, a neonicotinoid insecticide, and zinc pyrithione (Zpt), a biocide used in anti-dandruff shampoos and protective antifouling paints, to three species of ostracods and two waterfleas, including Daphnia magna, was determined and compared under light and dark conditions. Under normal laboratory conditions, UV light h...

A pilot-scale, ponded wetland consisting of an open pond and a vegetated pond in series was constructed on a cotton farm in northern New South Wales, Australia, and assessed for its potential to remove pesticides from irrigation tailwater. Ten incubation periods ranging from 7 to 13 days each were conducted over two cotton growing seasons to monito...

The acute toxicity of 468 organic pollutants to planktonic crustaceans (Branchiopoda, Copepoda and Ostracoda) from pre-existing data was compared by means of statistical analysis and relative tolerance indices (Trel). A surrogate species commonly used in toxicity bioassays (Daphnia magna) showed toxicity levels--within one order of magnitude--simil...

Biological effects of the biocide zinc pyrithione (Zpt), used in anti-dandruff shampoos and antifouling paints and the agricultural insecticide imidacloprid on Japanese medaka fish (Oryzias latipes) were assessed in experimental rice fields. Both chemicals are toxic to medaka, in particular Zpt, which also causes teratogenic effects such as spinal...

Although the use of endosulfan to control cotton pests has declined, this insecticide still has widespread application in agriculture and can contaminate riverine systems as runoff from soil or by aerial deposition. The degradation of endosulfan in pure water at different pH values of 5, 7 and 9 and in river water from the Namoi and the Hawkesbury...

Given the strict protocols for the registration of agrochemicals in developed countries there is a need to re-consider whether the use of PECs for the assessment of risks and/or hazards in aquatic environments is a valid approach. As the exposure of aquatic organisms in natural systems is reduced by several processes, more realistic values of effec...

Los estudios científicos realizados sobre diversos aspectos de la naturaleza en la Sierra de Candelario en los últimos decenios revelan el gran interés que tantos investigadores tienen por este macizo del Sistema Central. Debido a su altitud, influencia atlántica y aislamiento geográfico, la sierra ha servido de refugio a muchas especies animales y...

A site-specific methodology was developed to assess and compare the ecotoxicological risk that agricultural pesticides pose to ecosystems. The ecological relative risk (EcoRR) is a composite scoring index for comparing relative risks between different plant protection products, and is used to assess the potential ecological impact their residues ha...