When it comes to feeding on pollen, honeybees and bumblebees are generalists. They like a buffet of choices – except when it comes to pollen from flowers of the genus Cucurbita, including squash and pumpkin, which they avoid.
A Cornell study, “Pollen Defenses Negatively Impact Foraging and Fitness in a Generalist Bee,” published Feb. 20 in the journal Nature Scientific Reports, found that squash and pumpkin pollen have physical, nutritional and chemical defense qualities that are harmful to bumblebees.
“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.
Read more at Cornell University
Image: A bumblebee on a leaf leaves a trail of cucurbit pollen behind her as she tries to remove it. (Credit: Kristen Brochu, Cornell University)