Flower diversity may mitigate insecticide effects on wild bees

February 03, 2021

A higher diversity of flowering plants increases the breeding success of wild bees and may help compensate for the negative effects of insecticides. This is what researchers from the Universities of Göttingen and Hohenheim, as well as the Julius Kühn Institute, have found in a large-scale experimental study. The results have been published in the scientific journal Ecology Letters.

In their experiment, the researchers investigated how successfully the wild bee Osmia bicornis (red mason bee) reproduced. Red mason bees are important for both ecological and economic reasons. The wild bees were experimentally kept in more than 50 large enclosure cages with flower mixtures of varying wild plant diversity and insecticide-treated oilseed rape. Subsequently, the reproductive success of the wild bees, as measured by the number of their brood cells and emerged offspring, was investigated over several months.

The research team found that the number of cells that the wild bees created for their offspring where species-rich flowering mixtures were available was twice that of wild bees where only oilseed rape was available. The reproductive success of the wild bees, which have to supply their offspring with pollen and nectar, increased both in cages with a large diversity of flowering plants and where there were particularly important plant species. In contrast, if oilseed rape treated with clothianidin (from the neonicotinoid class of insecticides), was available to the bees, this had a negative effect on their reproductive success. However, this negative effect of the insecticide only occurred in cages with oilseed rape monocultures, which suggests that such effects can be mitigated by alternative food resources from species-rich flowering mixtures.

The study shows that both the diversity of flowering plants and exposure to insecticides significantly influence the reproductive success of wild bees, and shows that a high diversity of flowering plants could compensate for the negative effects of insecticides. "One possible explanation is that bee larvae benefit from additional nutrients, and are exposed to fewer insecticides, when the pollen of other plant species besides oilseed rape is available to them," explains Felix Klaus, first author of the study and PhD student in the Agroecology Group at Göttingen University. "Our results emphasise the important role of species-rich resources of flowers for wild bees," adds Professor Ingo Grass, head of the Department of Ecology of Tropical Agricultural Systems at the University of Hohenheim. "If sufficiently diverse flowers are available in the agricultural landscape, this could counteract the negative effects of monocultures and insecticides," says Professor Teja Tscharntke, Head of the Agroecology Group at Göttingen University.
Original publication: Felix Klaus et al. (2021): Floral resource diversification promotes solitary bee reproduction and may offset insecticide effects - evidence from a semi-field experiment. Ecology Letters. DOI: 10.1111/ele.13683 or here to see the paper: https://onlinelibrary.wiley.com/doi/full/10.1111/ele.13683


Felix Klaus
University of Göttingen
Faculty of Agricultural Sciences
Department of Crop Sciences - Agroecology Group
Grisebachstraße 6, 37077 Göttingen
Tel: +49 (0)551 3922359
Email: felix.klaus@uni-goettingen.de

Professor Teja Tscharntke
University of Göttingen
Faculty of Agricultural Sciences
Department of Crop Sciences - Agroecology Group
Tel: +49 (0)551 399209
Email: ttschar@gwdg.de

Professor Ingo Grass
University of Hohenheim
Department of Ecology of Tropical Agricultural Systems
Institute of Agricultural Sciences in the Tropics
Garbenstraße 13, 70599 Stuttgart
Tel: +49 (0) 711 459-22385,
Email: ingo.grass@uni-hohenheim.de

University of Göttingen

Related Bees Articles from Brightsurf:

Two pesticides approved for use in US harmful to bees
A previously banned insecticide, which was approved for agricultural use last year in the United States, is harmful for bees and other beneficial insects that are crucial for agriculture, and a second pesticide in widespread use also harms these insects.

Native bees also facing novel pandemic
There is growing evidence that another ''pandemic'' has been infecting bees around the world for the past two decades, and is spreading: a fungal pathogen known as Nosema.

Bees grooming each other can boost colony immunity
Honeybees that specialise in grooming their nestmates (allogroomers) to ward off pests play a central role in the colony, finds a new UCL and University of Florence study published in Scientific Reports.

Microalgae food for honey bees
A microscopic algae ('microalgae') could provide a complete and sustainably sourced supplemental diet to boost the robustness of managed honey bees, according to research just published by Agricultural Research Service scientists in the journal Apidologie.

Bees point to new evolutionary answers
Evolutionary biology aims to explain how new species arise and evolve to occupy myriad niches -- but it is not a singular or simplistic story.

Quantifying objects: bees recognize that six is more than four
A new study at the University of Cologne proves that insects can perform basic numerical cognition tasks.

Prescribed burns benefit bees
Freshly burned longleaf pine forests have more than double the total number of bees and bee species than similar forests that have not burned in over 50 years, according to new research from North Carolina State University.

Insecticides are becoming more toxic to honey bees
Researchers discover that neonicotinoid seed treatments are driving a dramatic increase in insecticide toxicity in U.S. agricultural landscapes, despite evidence that these treatments have little to no benefit in many crops.

Neonicotinoids: Despite EU moratorium, bees still at risk
Since 2013, a European Union moratorium has restricted the application of three neonicotinoids to crops that attract bees because of the harmful effects they are deemed to have on these insects.

Bees 'surf' atop water
Ever see a bee stuck in a pool? He's surfing to escape.

Read More: Bees News and Bees Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.