Experimental evidence that honeybees depress wild insect densities in a flowering crop

Research output: Contribution to journalArticle

Abstract

While addition of managed honeybees (Apis mellifera) improves pollination of many entomophilous crops, it is unknown if it simultaneously suppresses the densities of wild insects through competition. To investigate this, we added 624 honeybee hives to 23 fields of oilseed rape (Brassica napus L.) over 2 years and made sure that the areas around 21 other fields were free from honeybee hives. We demonstrate that honeybee addition depresses the densities of wild insects (bumblebees, solitary bees, hoverflies, marchflies, other flies, and other flying and flower-visiting insects) even in a massive flower resource such as oilseed rape. The effect was independent of the complexity of the surrounding landscape, but increased with the size of the crop field, which suggests that the effect was caused by spatial displacement of wild insects. Our results have potential implications both for the pollination of crops (if displacement of wild pollinators offsets benefits achieved by adding honeybees) and for conservation of wild insects (if displacement results in negative fitness consequences).

Details

Authors
Organisations
External organisations
  • Swedish University of Agricultural Sciences
  • Swedish Rural Economy and Agricultural Society
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Environmental Sciences related to Agriculture and Land-use
  • Ecology

Keywords

  • Crop pollinators, Flies, Interspecific competition, Oilseed rape, Wild bees
Original languageEnglish
Article number20161641
JournalProceedings of the Royal Society B: Biological Sciences
Volume283
Issue number1843
StatePublished - 2016 Nov 30
Peer-reviewedYes