Squash Bees have played an important for centuries.
One of many species of ground bees, but they have a very specialized roll.
The most widespread species,Peponapis pruinosa, is found from Quebec southward into Mexico, wherever squashes are grown.
Do you grow squash, pumpkins or gourds?
If so, you have the chance to see the most important floral specialists in agriculture, native solitary bees of two genera, Peponapis and Xenoglossa, the so-called "Squash-Bees". Look at your squash’s flowers during the first few hours after sunrise. Male squash bees will be darting between flowers, searching for mates.
Females forage at the flowers of squashes, pumpkins and gourds, their sole pollen hosts.
By noon, these specialized bees will be fast asleep.
The squashes (including pumpkins and gourds) are a crop native to the Americas that require a special pollinator. Squashes are big business, a half billion dollar crop in the USA alone, and that does not count the huge quantities grown in home gardens.
Only the past few years have commercial pumpkin and squash growers learning the importance of this specialized native bee and realize the value of planting new or expanded areas near the old growing site where the bees already exist.
Squash flowers are unisexual, and so require a bee (or human) to move pollen from male to female flowers.
Honeybees are typically provided for commercial squash pollination, but native specialist squash and pumpkin bees, are very common, often the dominant pollinators of many wild New World Cucurbita (the genus that includes squashes and gourds).
Where squash cultivation has extended beyond the ranges of wild plants, Squash bees have followed (in North America, anywhere outside the Southwest; in South America, areas of southern Brazil).
In contrast to like-sized honey bees, Squash type bees, carry their pollen dry in a brush of hairs on their body and hind legs.
The bees are non-social, but occasionally gregarious (they like to nest together), ground-nesters, and all species are strict specialists for Cucurbita pollen.
They forage early in the morning, beginning before honey bees are active, and have been shown to be excellent pollinators of several kinds of both winter and summer squashes.
Squash Bees nest underground, typically a tunnel a foot or so beneath the surface, and are much less noticeable than the above ground homes of other bees. This might help explain why even the people who grow pumpkins for fun or for profit may be oblivious to the busy little bees.
Underground nests, require well-drained areas in which to burrow. Adults live just a few months, from mid to late summer when the squash plants are in flower.
Females are ground-nesters, each digging her own tunnel and constructing chambers for her eggs. Like other ground-nesting bees, their nests can sometimes be found in large numbers when many females locate the same quality habitat. Leaving bare patches of soil on your property could provide vital nesting habitat for these and other native bees.
Be careful laying down mulch, these insects cannot burrow through the thick layer and will die underground.
Both male and female bees take up the blooms’ sweet nectar. But only the females seek the orange pollen grains, munching on or carrying the grains and nectar back to their nests as provisions for their offspring.
Blooms will have closed by midday, and squash bees will have all but disappeared from view. The wiliest of the males will be spending the rest of their day—and night—sleeping peacefully in a flower.
The next morning, these plan-ahead Romancers will be fully refreshed and ready to romance unsuspecting females that begin to arrive as soon as flowers open.
You might enjoy getting up early one morning to look for these bees.
Numerous, Squash bees will thoroughly pollinate all available flowers, rendering flower visits of later-flying bees a non factor for pollination. Before honey bees were introduced to the Americas by European colonists, it is evident that these bees were critical to the adoption, domestication, spread and production of Cucurbita by native peoples throughout the Americas.
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