Insect decline and its drivers: Unsupported conclusions in a poorly performed meta-analysis on trends—A critique of Sánchez-Bayo and Wyckhuys (2019)

Mupepele, Anne‐Christine; Bruelheide, Helge; Dauber, Jens; Krüß, Andreas; Potthast, Thomas; Wägele, Wolfgang; Klein, Alexandra‐Maria

doi:10.1016/j.baae.2019.04.001

Cited by 20 publications

(17 citation statements)

References 10 publications

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“…The Sánchez-Bayo and Wyckhuys (2019) paper that reviewed declines and the associated media stories are not without their critics, highlighting many issues around geographical, taxonomic and methodological biases that have purportedly undermined both the peer review process and insect conservation efforts (Leather, 2018;Cardoso et al, 2019;Mupepele et al, 2019;Saunders, 2019;Simmons et al, 2019;Thomas et al, 2019;Wagner, 2019). Yet, at the level of Insecta, many scientists would agree anecdotally that insect declines have happened in their lifetime, at least in many parts of the world (McCarthy, 2015: Vogel, 2017Janzen & Hallwachs, 2019), and instead the dispute is likely around the rate rather than the existence of a decline for most groups.…”

Section: Introductionmentioning

confidence: 99%

“…Even after the widespread habitat destruction during World War I, it is perhaps surprising that butterflies and moths saw a reversal in fortunes, although there are exceptions (Bretherton, 1951). Whilst it is rarely recognised or cited that insects may profit as a result of environmental change (Bell et al, 2015;Herrera, 2019, Boyes et al, 2019, Macgregor et al, 2019, it adds a dimension to the question of whether insects are declining and if so at what rate, because it suggests that to answer such a question will be dependent on the species or group studied, ignoring other likely important covariates such as habitat, spatio-temporal issues, statistical methodology and sampling intensity and bias, for example (McKinney, 1999;Cardoso et al, 2019;Mupepele et al, 2019;Simmons et al, 2019;Thomas et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

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Are insects declining and at what rate? An analysis of standardised, systematic catches of aphid and moth abundances across Great Britain

Bell

Blumgart

Shortall

2020

Insect Conserv Diversity

100

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Although we have known anecdotally that insects have been declining in Great Britain for more than 100 years, insect declines have only been statistically estimated over the last 20 years. Estimation of the rate of those declines is still hotly debated, fuelled by a lack of standardised, systematically collected data. More than 24 million individual moths and aphids collected from 112 light traps and 25 12.2 m suction‐traps, respectively, were analysed using mixed models. Our objective was to estimate the long‐term trends in both groups based on annual totals recorded every year between 1969 and 2016. The models showed that two paradigms existed: Over 47 years, long‐term linear trends showed that moths had declined significantly by −31%, but short‐term trends indicated that there were periods of significant decline and recovery in most decades since the 1960s. Conversely, despite aphid annual totals fluctuating widely, this group was in a steady state over the long‐term, with a non‐significant decline of −7.6%. Sensitivity analysis revealed that moth trends were not driven by a group of abundant species, but the sign of the overall aphid trends may have been driven by three of the most abundant species. The spatial extent of moth trends suggests that they are extremely heterogeneous. Uniquely, moth declines were different among several habitat types, with robust significant declines found in coastal, urban and woodland habitats, but notably not in agricultural, parkland and scrubland habitats. Conversely, aphid trends showed spatial synchrony extending to 338 km, albeit with local variation.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Are insects declining and at what rate? An analysis of standardised, systematic catches of aphid and moth abundances across Great Britain

Bell

Blumgart

Shortall

2020

Insect Conserv Diversity

100

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“…The scientific response to this has been an exemplar of the nature of science as a self-correcting endeavour, with critical re-evaluation of the findings emerging rapidly (e.g. Willig et al, 2019;Cardoso & Leather, 2019;Komonen et al, 2019;Montgomery et al, 2020Mupepele et al, 2019Simmons et al, 2019;Thomas et al, 2019;Wagner, 2019;Saunders et al, 2020a). The global media response has been something entirely different but has put insect conservation firmly on the public and policy agenda (Harvey et al, 2020).…”

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confidence: 99%

Interpreting insect declines: seven challenges and a way forward

Didham

Basset

Collins

et al. 2020

Insect Conserv Diversity

320

355

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Many insect species are under threat from the anthropogenic drivers of global change. There have been numerous well‐documented examples of insect population declines and extinctions in the scientific literature, but recent weaker studies making extreme claims of a global crisis have drawn widespread media coverage and brought unprecedented public attention. This spotlight might be a double‐edged sword if the veracity of alarmist insect decline statements do not stand up to close scrutiny. We identify seven key challenges in drawing robust inference about insect population declines: establishment of the historical baseline, representativeness of site selection, robustness of time series trend estimation, mitigation of detection bias effects, and ability to account for potential artefacts of density dependence, phenological shifts and scale‐dependence in extrapolation from sample abundance to population‐level inference. Insect population fluctuations are complex. Greater care is needed when evaluating evidence for population trends and in identifying drivers of those trends. We present guidelines for best‐practise approaches that avoid methodological errors, mitigate potential biases and produce more robust analyses of time series trends. Despite many existing challenges and pitfalls, we present a forward‐looking prospectus for the future of insect population monitoring, highlighting opportunities for more creative exploitation of existing baseline data, technological advances in sampling and novel computational approaches. Entomologists cannot tackle these challenges alone, and it is only through collaboration with citizen scientists, other research scientists in many disciplines, and data analysts that the next generation of researchers will bridge the gap between little bugs and big data.

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“…There are increasing concerns about the effects of pesticide on nontarget animals. Recent reports have indicated a large decline in entomofauna that may, according to a review, result in the future extinction of ∼ 40% of species; however, and importantly, further reports have pointed to limitations or incorrect data interpretation in that study . Most attention regarding pesticide side effects has been focused on diverse pollinators due to their global decline, and bees are the best documented taxon to be affected by pesticides .…”

Section: Introductionmentioning

confidence: 99%

“…Recent reports have indicated a large decline in entomofauna that may, according to a review, result in the future extinction of ∼ 40% of species 1 ; however, and importantly, further reports have pointed to limitations or incorrect data interpretation in that study. 2,3 Most attention regarding pesticide side effects has been focused on diverse pollinators due to their global decline, and bees are the best documented taxon to be affected by pesticides. [4][5][6][7] In general, a number of studies link the use of pesticides (at least partially) with the decline in entomofauna, including pollinators.…”

Section: Introductionmentioning

confidence: 99%

Pesticide comparison of Phylloneta impressa (Araneae: Theridiidae) females, cocoons and webs with prey remnants collected from a rape field before the harvest

Erban

Sopko

Václavíková

et al. 2019

Pest Management Science

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BACKGROUND Pesticides or plant protection products (PPPs) are risky for spiders in or near agricultural landscapes. However, the risks posed by pesticides to spiders are largely understudied compared with the risks to pollinators. Here, we investigated the distribution of PPPs in adult females, cocoons and webs with prey remnants of Phylloneta impressa. RESULTS Three sample types were collected from the tops of rapeseed on 18 July (before the harvest). Three different ultraperformance liquid chromatograph coupled with triple‐quadrupole tandem mass spectrometer (UHPLC–QqQ–MS/MS) analyses were performed: (i) pesticides and selected metabolites; (ii) quaternary ammonium pesticides (quats); and (iii) pyrethroids. Overall, 23 compounds, 22 pesticides and the metabolite imidacloprid‐urea were detected. The array of pesticides was largest in webs with prey remnants, and according to evaluation via redundancy analysis (RDA), pesticides were similar in spiders and cocoons; however, data inspection revealed differences in pesticide distribution among these samples. Clothianidin was detected in only female spiders, whereas thiamethoxam prevailed in webs with remnants of prey, and acetamiprid, thiacloprid and imidacloprid were found in all three matrices. One of the most abundant compounds was chlormequat, indicating that quats should be considered a possible risk for these spiders. None of the pyrethroids were detected despite being applied in the sampling area, indicating rapid biodegradation. By contrast, some pesticides were detected despite not being applied in the field, indicating that the source of contamination is prey or particles carried by wind and attached to webs. CONCLUSION Overall, the results indicate the different distribution or behavior of several pesticides in the spider matrices. © 2019 Society of Chemical Industry

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Insect decline and its drivers: Unsupported conclusions in a poorly performed meta-analysis on trends—A critique of Sánchez-Bayo and Wyckhuys (2019)

Cited by 20 publications

References 10 publications

Are insects declining and at what rate? An analysis of standardised, systematic catches of aphid and moth abundances across Great Britain

Are insects declining and at what rate? An analysis of standardised, systematic catches of aphid and moth abundances across Great Britain

Interpreting insect declines: seven challenges and a way forward

Pesticide comparison of Phylloneta impressa (Araneae: Theridiidae) females, cocoons and webs with prey remnants collected from a rape field before the harvest

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