Nav: Home

Bumblebees aversion to pumpkin pollen may help plants thrive

March 11, 2020

ITHACA, N.Y. - Cornell University researchers have found that squash and pumpkin pollen have physical, nutritional and chemical defense qualities that are harmful to bumblebees. The results of their recent study suggest that deterring bumblebees from collecting and eating pollen may provide an evolutionary benefit to cucurbit plants.

"When bumblebees are fed cucurbit pollen, it causes all kinds of problems," said Bryan Danforth, professor of entomology and the paper's senior author. "Adults have damaged and distorted digestive tracts and colonies fed cucurbit pollen failed to rear any offspring."

Bumblebees do visit pumpkin and squash flowers for the nectar, and though they don't collect the pollen, some might inadvertently get on their legs. However, these bees that visit plants for nectar but don't collect pollen may be good pollinators, as stray pollen on their bodies may end up pollinating the next flower.

"I actually saw them in the field using their legs to groom it off their bodies and then wipe it on a leaf," said first author Kristen Brochu, a former Cornell doctoral student in Danforth's lab and a postdoctoral researcher at Pennsylvania State University. "Not only are they not collecting it, they actually hate it."

In the study, Brochu and colleagues created diets that represented different defenses to test which cucurbit pollen characteristics deterred bumblebees. Microcolonies of five bees were each fed a separate treatment. The bees fed wildflower pollen thrived, as expected. Under a natural cucurbit diet, the cumulative effect of the pollen's physical defenses, poor nutritional content and chemicals led to bees ejecting their offspring from their brood cells and killing them. Bumblebees do this when stressed, possibly because they can't take care of the larvae, Brochu said.

In a third treatment, the team extracted the chemicals from the cucurbit pollen and added them to the control diet of nutritionally rich wildflower pollen. With the crushed pollen diet, where the pollen's physical defenses were removed, eggs and larvae failed to mature. "Over the course of the 50 days of the experiment, in both the crushed and natural cucurbit treatment, no offspring made it to adulthood," Brochu said.

In the crushed treatment, the adults also died at a higher rate, possibly due to a release of additional toxic chemicals.

For the sake of bumblebees, she said, pumpkin and squash growers may think twice about bringing commercial bumblebees into their fields and may provide wildflower strips as alternative food sources.
-end-
The study, "Pollen Defenses Negatively Impact Foraging and Fitness in a Generalist Bee," published in the journal Nature Scientific Reports.

Study co-authors include Brian Nault, professor of entomology at Cornell AgriTech, and Jessica Peterson, a former postdoctoral researcher in Nault's lab who is an invertebrate ecologist at the Minnesota Department of Natural Resources.

Cornell University has dedicated television and audio studios available for media interviews supporting full HD, ISDN and web-based platforms.

Cornell University

Related Bees Articles:

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.
More Bees News and Bees Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Power Of Spaces
How do spaces shape the human experience? In what ways do our rooms, homes, and buildings give us meaning and purpose? This hour, TED speakers explore the power of the spaces we make and inhabit. Guests include architect Michael Murphy, musician David Byrne, artist Es Devlin, and architect Siamak Hariri.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at Radiolab.org/donate.     You can read The Transition Integrity Project's report here.