Non-native honeybees are so effective at pollinating, they pose a significant threat to native California bees and other pollinators, according to a study published by UC San Diego biologists Monday.
Brought over to North America partially because of their effectiveness, populations of feral European honeybees have proliferated in the American Southwest. While nearly all plants need pollinators, these invasive bees make up nearly 90% of bees visiting flowers of multiple native plant species in the region, the report found.
The study was published in the journal Insect Conservation and Diversity, a Royal Entomological Society journal. In it, the authors estimate the impact honey bees may be having on populations of native bees. According to their findings, honeybees remove about 80% of pollen during the first day that a flower opens.
All bees in the region — and the vast majority of bee species worldwide — use pollen to raise their offspring. The amount of pollen removed daily by honey bees from just 2.5 acres of native vegetation is enough to provision thousands of native bees per day during the peak bloom of native shrubs, the researchers found.
“Although honeybees are rightly considered an indispensable asset to humans, they can also pose a serious ecological threat to natural ecosystems where they are not native,” said biologist Keng-Lou James Hung, who earned his PhD from UCSD and is now an assistant professor at the University of Oklahoma.
“The plight of the honey bee is an issue of animal husbandry and livestock management, whereas when it comes to conservation issues here in North America, honey bees are likelier to be part of the problem, not a solution or a target for conservation.”
In addition to their speed, honeybees are larger than most native bee species in Southern California — now comprising 98% of all bee biomass. If the pollen and nectar used to create honey bee biomass were instead converted to native bees, populations of native bees would be expected to be roughly 50 times larger than they are currently, a statement from UCSD reads.
Hung’s co-authors, Dillon Travis and Joshua Kohn, found in a 2023 study that plants pollinated by non-native honeybees actually produce lower-quality offspring compared to those pollinated by native bees.
“Public concern for honey bees often fails to consider their potential negative effects on native pollinators,” the authors write.
“Honey bees are incredibly effective at extracting resources like pollen and nectar,” said Travis, who earned his PhD at UCSD in 2023. “Unlike the vast majority of native bee species in the region, honey bees can communicate to their nestmates the locations of rewarding plants and quickly remove most of the pollen, often early in the morning before native bees begin searching for food.”
The researchers used pollen-removal experiments to estimate the amount of pollen extracted by honeybees using three common native plants: black sage, white sage and distant phacelia. They found that just two visits by honeybees removed more than 60% of the available pollen from flowers of all three species.
The more than 700 species of bees native to Southern California had the remainder to fight over.
“The most surprising finding was the extraordinarily small number of individual native bees observed that were as large or larger than honey bees,” said Kohn, professor emeritus of the UCSD’s Department of Ecology, Behavior and Evolution. “Particularly rare were bumble bees, which made up only 0.1% of all bees we observed.”
The authors said more attention should be paid to the resource consumption of honeybees amid the decline of native pollinator populations. They suggest limiting where commercial beekeepers are allowed to keep hives after crops have bloomed as a potential solution.
“In areas with threatened bee species, natural preserve managers may also want to consider systematic removals or relocations of non-native honey bee colonies to provide wild bees a fighting chance,” Hung said.
David Holway was an additional co-author on the report published Monday.
City News Service contributed to this article.
Read More Details
Finally We wish PressBee provided you with enough information of ( UCSD study warns: Non-native honey bees threaten food supply for native pollinators )
Also on site :
- Possible tornado in Phelps on Monday
- Evacuations ordered after brush fire breaks out in Laguna Beach
- Photos: A blaze at Cairo telecommunications building causes service disruptions