Title: The potential of weeds in arable fields to support pollinator assemblages

Weeds on arable land are known to be useful to pollinators but to what extent? The study sampled the weed flora in fields under conventional or organic farming in SE Sweden and examined the frequency of flowering among weeds that scored high on a pollinator index, henceforth ‘pollinator-friendly weeds’.

Also sampled were pollinating insects within cereal crops using transect walks and colour pan traps.

As expected, weeds were ubiquitous and occurred in most sampling plots. In the pan traps, more than 100 species of pollnators were caught, including 26 Syrphidae, 19 social bees, 37 solitary bees and 22 other Hymenoptera.

In the transects walks, the probability of encountering bees increased with flowering of pollinator-friendly weeds, and there was a similar but weaker pattern among hoverflies.

Organically grown fields differed from conventional ones by having more pollinator-friendly weeds, more flowering of such weeds, and more bees. There was also a tendency for hoverflies and other Hymenoptera to be more abundant in organic fields.

Three conclusions emerged. First, pollinator-friendly weeds made up one third to almost half of the weed occurrences recorded. Second, substantial numbers of pollinators searched for flowers within arable fields, and some increased with the abundance of flowering of pollinator-friendly weeds. Third, flowering pollinator-friendly weeds and some pollinators were more abundant in organic fields than in conventional ones.

Overall, the showed that weeds on arable land are a potential and sought after resource among pollinators, and that even conventionally grown crops should be considered a potential habitat for bees.

Milberg, P., Bergman, K.-O., Björklund, L. & Westerberg, L. (2025). The potential of weeds in arable fields to support pollinator assemblages. Weed Research, 65(1), e12673. Full-text vailable from: https://doi.org/10.1111/wre.12673



Attachments:
pollinators in arable fields.jpg
Article: WeedsNews6743 (permalink)
Categories: :WeedsNews:research alert, :WeedsNews:bees, :WeedsNews:organic farming, :WeedsNews:beneficial weeds, :WeedsNews:biological control
Date: 26 February 2025; 2:53:39 PM AEDT

Author Name: David Low
Author ID: adminDavid