Honey bees are the dominant diurnal pollinator of native m

What this paper is about

Common milkweed is planted widely in cities for monarchs, but who actually pollinates it there had not been established.

Surveys through the July flowering period in a large urban park found honey bees, a managed non-native species, were the dominant daytime pollinator.

Summarised here from the abstract below. Not the authors’ words.

Abstract

In eastern North America, the field milkweed, Asclepias syriaca L. (Asclepiadaceae), is used in planting schemes to promote biodiversity conservation for numerous insects including the endangered monarch butterfly, Danaus plexippus (Linnaeus) (Nymphalidae). Less is known about its pollinators, and especially in urban habitats where it is planted often despite being under increasing pressure from invasive plant species, such as the related milkweed, the dog-strangling vine (DSV), Vincetoxicum rossicum (Kleopow) Barbar. (Asclepiadaceae). During the A. syriaca flowering period in July 2016, we surveyed bees in open habitats along a DSV invasion gradient and inspected 433 individuals of 25 bee species in 12 genera for pollinia: these were affixed to bees that visited A. syriaca for nectar and contain pollen packets that are vectored (e.g., transferred) between flowers. Of all bees sampled, pollinia were found only on the nonindigenous honeybee, Apis mellifera (43% of all bees identified), as well as one individual bumblebee, Bombus impatiens Cresson. Pollinia were recorded from 45.2% of all honeybees collected. We found no relationship between biomass of DSV and biomass of A. syriaca per site. There was a significant positive correlation between A. syriaca biomass and the number of pollinia, and the proportion vectored. No relationship with DSV biomass was detected for the number of pollinia collected by bees but the proportion of vectored pollinia declined with increasing DSV biomass. Although we find no evidence of DSV flowers attracting potential pollinators away from A. syriaca and other flowering plants, the impacts on native plant-pollinator mutualisms relate to its ability to outcompete native plants. As wild bees do not appear to visit DSV flowers, it could be altering the landscape to one which honeybees are more tolerant than native wild bees.

Abstract reproduced from the published paper, which is licensed CC BY. Copyright remains with the authors.

Key terms

PollinationApis melliferaInvasive plantsUrbanHost ShiftPollinia

Milkweeds in this paper

Common Milkweed Asclepias syriaca

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APA

Milkweed USA. (2026). Honey bees are the dominant diurnal pollinator of native milkweed in a large urban park (listing). Retrieved DATE, from https://milkweedusa.com/research/honey-bees-are-the-dominant-diurnal-pollinator-of-native-2017/

MLA

"Honey bees are the dominant diurnal pollinator of native milkweed in a large urban park (listing)." Milkweed USA, 2026, https://milkweedusa.com/research/honey-bees-are-the-dominant-diurnal-pollinator-of-native-2017/. Accessed DATE.

Chicago

Milkweed USA. "Honey bees are the dominant diurnal pollinator of native milkweed in a large urban park (listing)." Last modified 2026-08-01. Accessed DATE. https://milkweedusa.com/research/honey-bees-are-the-dominant-diurnal-pollinator-of-native-2017/.

BibTeX

@misc{milkweedusa_researchhoneybeesarethedomin,
  title  = {Honey bees are the dominant diurnal pollinator of native milkweed in a large urban park (listing)},
  author = {{Milkweed USA}},
  year   = {2026},
  url    = {https://milkweedusa.com/research/honey-bees-are-the-dominant-diurnal-pollinator-of-native-2017/},
  note   = {Accessed DATE}
}