I don’t grow pumpkins or squash. But I have been visiting a couple of farms searching for an industrious little native bee, capable of pollinating their huge, bright yellow flowers with great efficiency. It is known as the squash bee, and it specializes on flowers of the cucurbit family: pumpkin, squash, zucchini, etc. Honey bees, bumble bees, and several types of halictid bees also visit the flowers, but none is as skilled as this specialist bee.
I am collecting these pollinators to help a researcher at Cornell University who is studying them, gathering data throughout the country. There are two types of squash bees. The one we are interested in goes by the scientific name of Peponapis pruinosa. The scientific name is very descriptive, Peponapis means squash bee; pruinosa means covered with hoar-frost, which refers to the soft fuzz coating its thorax. It is about the same size as a honey bee and of similar coloration, but when you have been looking at them for a while, you have no trouble telling them apart.
The squash bee has abdominal stripes a little more pronounced than those of a honey bee, and the end of the abdomen is a little pointier. The back legs look quite different. Squash bees have hairy combs to carry pollen; honey bees have baskets, a flattened area surrounded by strong bristles. You can also tell them apart by their behavior: squash bees are all business. They waste no time, diligently going from flower to flower. Honey bees and bumble bees are inclined to dilly-dallying; all and all, they don’t visit or pollinate as many flowers.
At times, it has been a frustrating search. I finally managed to gather a satisfactory number of bees; but there were days in which I came home empty handed, or nearly so. Probably the reason is that the farms that I visit are close to the suburbs where I live. One member of the team tells me that other pumpkin patches, located in rural areas, are full of busy squash bees during this season. It would seem that the suburban landscape, so impoverished on native trees and shrubs, fails to provide the habitat needed by squash bees.
It is worth remembering that squash bees and cucurbit plants are long-term partners. They have been fine tuning their relationship for millions of years, long before Europeans brought honey bees to this continent. For a long time, farmers have relied solely on that jack-of-all-trades, the domestic bee, for all pollination. They are finally developing a new respect for these specialist bees.
I hope that this research contributes to the appreciation of these native bees, their value to crops, and the importance of natural surroundings to ensure their welfare.
Photos by Beatriz Moisset
© 2011, Beatriz Moisset. All rights reserved. This article is the property of Native Plants and Wildlife Gardens. If you are reading this at another site, please report that to us