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Data from: Floral resource diversification promotes solitary bee reproduction and may offset insecticide effects – evidence from a semi-field experiment

Citation

Klaus, Felix; Tscharntke, Teja; Bischoff, Gabriela; Grass, Ingo (2022), Data from: Floral resource diversification promotes solitary bee reproduction and may offset insecticide effects – evidence from a semi-field experiment, Dryad, Dataset, https://doi.org/10.5061/dryad.wdbrv15n7

Abstract

Pollinator declines in agricultural landscapes are driven by multiple stressors, but potential interactions of these remain poorly studied. Using a highly replicated semi-field study with 56 mesocosms of varying wild plant diversity (2-16 species) and oilseed rape treated with a neonicotinoid, we tested the interacting effects of resource diversity and insecticides on reproduction of a solitary wild bee. Compared to mesocosms with oilseed rape monocultures, availability of resources from wild plants complementing oilseed rape doubled brood cell production. In addition, bee reproduction increased due to plant diversity and identity effects. Exposure to neonicotinoid-treated oilseed rape reduced bee larval to adult development by 69%, but only in mesocosms with oilseed rape monocultures. Availability of complementary flower resources can thus offset negative effects of neonicotinoid-treated oilseed rape on wild bee reproduction. Policy should encourage the implementation of diverse floral resources mitigating negative effects of crop monocultures and insecticides, thereby sustaining solitary bee populations in agricultural landscapes.

Methods

Method of estimating flower numbers: In every sampling round, the number of flowers of all flowering plant species in each mesocosm were estimated, to be able to quantify resources available to nesting bees. For flower estimations, small patches of each flowering species were counted, and the total numbers for each mesocosm were then estimated based on these counts. For Asteraceae, we defined one flower as one flower head.

Funding

Deutsche Forschungsgemeinschaft, Award: 152112243