More than 75 percent decline over 27 years in total flying insect biomass in protected areas.
Caspar A. Hallmann,Martin Sorg,Eelke Jongejans,Henk Siepel,Nick Hofland,Heinz Schwan,Werner Stenmans,Andreas Müller,Hubert Sumser,Thomas Hörren,Dave Goulson,Hans de Kroon +11 more
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This analysis estimates a seasonal decline of 76%, and mid-summer decline of 82% in flying insect biomass over the 27 years of study, and shows that this decline is apparent regardless of habitat type, while changes in weather, land use, and habitat characteristics cannot explain this overall decline.Abstract:
Global declines in insects have sparked wide interest among scientists, politicians, and the general public. Loss of insect diversity and abundance is expected to provoke cascading effects on food webs and to jeopardize ecosystem services. Our understanding of the extent and underlying causes of this decline is based on the abundance of single species or taxonomic groups only, rather than changes in insect biomass which is more relevant for ecological functioning. Here, we used a standardized protocol to measure total insect biomass using Malaise traps, deployed over 27 years in 63 nature protection areas in Germany (96 unique location-year combinations) to infer on the status and trend of local entomofauna. Our analysis estimates a seasonal decline of 76%, and mid-summer decline of 82% in flying insect biomass over the 27 years of study. We show that this decline is apparent regardless of habitat type, while changes in weather, land use, and habitat characteristics cannot explain this overall decline. This yet unrecognized loss of insect biomass must be taken into account in evaluating declines in abundance of species depending on insects as a food source, and ecosystem functioning in the European landscape.read more
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Neonicotinoids disrupt memory, circadian behaviour and sleep.
TL;DR: In this article, the effect of field-relevant concentrations of the European Union-banned neonicotinoids: imidacloprid, clothianidin, thiamethoxam and thiacloprid were tested on Drosophila memory, circadian rhythms and sleep.
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Addressing behavior in pollinator conservation policies to combat the implementation gap.
Melissa R. Marselle,Melissa R. Marselle,Anne Turbé,Assaf Shwartz,Aletta Bonn,Aletta Bonn,Agathe Colléony +6 more
TL;DR: A gap analysis of conservation behavior change interventions advocated in national conservation strategies using the Behaviour Change Wheel (BCW), a comprehensive framework for systematically characterizing and designingbehavior change interventions, finds that these initiatives failed to employ the whole breadth of behavioral interventions.
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Factors affecting the efficiency of molecular species delimitation in a species-rich insect family.
Abstract: In the context of global biodiversity loss, molecular species delimitation approaches can be very useful for accelerating species discovery through DNA taxonomy and inventory through DNA metabarcoding. In this study, the effect of some intrinsic factors on the efficiency of various single-marker species delimitation methods (fixed and variable nucleotide distance thresholds, ABGD, ASAP, GMYC, mPTP) was tested on more than 90 empirical data sets, derived from a set of 7,237 COI sequences attributed to 542 leaf beetles species (Coleoptera: Chrysomelidae). The considered factors were: (i) the number of haplotypes per species (as a proxy for genetic diversity), (ii) the geographic distance among conspecific collection localities (as a proxy of sampling width), (iii) the difficulty related to morphological identification of species, and (iv) the taxonomic rank. Distance-based methods, with on average more than 70% of match with morphological identification, outperformed those relying on phylogenetic trees, with less than 59%. A high number of haplotypes per species was found to have a negative effect on delimitation efficiency, whereas large geographic distances within species had a positive effect. All methods delimitations (except for GMYC) were significantly affected by the presence of species that are difficult to be identified, decreasing their efficiency. Finally, the only method influenced by the taxonomic rank of the data set was GMYC, showing lower efficiency in data sets at the genus than at higher levels. The observed biases we highlighted affecting efficiency could be accounted for when developing input data sets for species delimitation analyses to obtain a more reliable representation of biological diversity.
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Collecting insects to conserve them: a call for ethical caution
Bob Fischer,Brendon M. H. Larson +1 more
TL;DR: The Three Rs, guidelines proposed in 1959 by WMS Russell and RL Burch that have become the dominant way of thinking about the ethics of using animals in research, are adapted and there is reason to adopt it in a modified form to mitigate moral risk especially in the context of conservation.
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Critical Decline of Earthworms from Organic Origins under Intensive, Humic SOM-Depleting Agriculture
TL;DR: In this paper, the situation pertaining to neglected earthworms was investigated, and the probable cause of general loss was lack of recruitment from surrounding fields (except for pest species), thus earthworms are conclusively shown to be similarly depleted from their optima in agrichemical fields.
References
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TL;DR: The nature and extent of reported declines, and the potential drivers of pollinator loss are described, including habitat loss and fragmentation, agrochemicals, pathogens, alien species, climate change and the interactions between them are reviewed.
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