Truth, comms, both?
Sunflowers make bees poop—a lot. Here’s why that’s good.
The flower’s pollen works like a medicine for bumblebees afflicted with a nasty parasite.
Bumblebees and other pollinators face many threats, including pesticide exposure, climate change, habitat loss due to agriculture and development, and pathogens that ravage multiple species. But a recent finding may help lighten their load.
Previous studies have shown sunflower pollen can work like a medicine for bumblebees afflicted by a parasite called Crithidia bombi, a single-celled organism that takes up residence in the bee’s gut and harms their health. But scientists couldn’t explain how sunflower pollen vanquished C. bombi—did it boost the bees’ immune function, or perhaps poison the parasite directly?
New research, published in the Journal of Insect Physiology, shows the answer is deceptively simple. “Sunflower pollen makes bumblebees poo a whole lot,” says lead author Jonathan Giacomini, which flushes the parasite out.
Plant products like nectar and pollen are a treasure trove of potential insect medicines that scientists are just beginning to understand, he adds. “There are natural things out there that bees are interacting with that can be beneficial for them,” Giacomini says. And by making changes to the landscape, scientists hope we can help give bees a fighting chance.
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Giacomini discovered the effect of sunflower pollen as an undergraduate working in Adler’s lab in 2018. From the very first tests, sunflower pollen dramatically reduced C. bombi parasite load in common eastern bumblebees, often clearing infection completely. “We’ve been shocked at how consistent and effective sunflower pollen has been,” Adler says.
But they couldn’t figure out how—separate studies over the years ruled out immune function boosts and were unable to pin down any chemical compounds in sunflower pollen that would spell doom for C. bombi.
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Giacomini fed sunflower pollen to healthy bumblebees and bumblebees infected with C. bombi, then compared their excretions to other bees that received only wildflower pollen. (Bumblebees don’t separate their solid and liquid waste like we do, so bumblebee poo is a thin slurry that’s often bright yellow from undigested pollen.)
“It turned out that bee poop naturally fluoresces under ultraviolet light,” which made distinguishing between poo and non-poo remarkably easy, Giacomini recalls. “It was very dazzling—it almost looked like a galaxy.”
Regardless of whether they were infected or not, bees that ate sunflower pollen pooped 68 percent more in volume and 66 percent more frequently than bees that ate wildflower pollen alone.
The natural next question was why sunflower pollen had this effect. There are lots of ways to get the bowels moving—osmotic laxatives soften stool with extra water, while stimulant laxatives prompt the muscles of the gut to massage digested food down and out.
But preliminary research from the Adler lab again suggests a surprisingly simple explanation. Sunflower pollen’s outer shell is very spikey, which may irritate the lining of the gut into producing a lubricating mucus or somehow dislodge the parasite. According to as-yet unpublished data, Adler says bees fed the outer shell alone experience the same bathroom disruptions and anti-parasite effects, while bees fed the core of sunflower pollen did not.
Moar at link.
https://www.nationalgeographic.com/animals/article/sunflowers-vanquish-bumblebee-parasites?cmpid=org=ngp::mc=social::src=twitter::cmp=editorial::add=tw202211208animals-sunflowersbeeparasites&linkId=193278964