Mid to Late Summer Bees

Every party has its fashionably late arrivals, some of which really know how to make an entrance. And let’s not forget those inevitable guests with special dietary requirements. Your mid-summer garden will host all of these native bee visitors and more.

 

Long-horned bees (genus Melissodes) are among the most easily recognized native bees in our residential gardens. The eye-catching appearance of male and female long-horned bees on the garden scene heralds the arrival of midsummer. This fashionable pair definitely deserves a best-dressed couple award; the males sport extremely long antennae, and the females have such prominent scopae (specialized pollen-carrying hairs) on their hind legs that, when loaded with pollen, they resemble plush golden leg warmers.

 

Male long-horned bees have especially long antennae.

Female long-horned bees have pronounced pollen brushes on their hind legs. Photos by Celeste Ets-Hokin.

Both males and females are small- to medium-sized, robust, hairy bees, often having noticeably striped abdomens. Melissodes species are sometimes referred to as sunflower bees because they are important pollinators of both wild and hybrid sunflowers. These ground-nesting bees will often make their nests very near the base of sunflowers or other preferred forage plants. Some of these favorite summer flowers include Cosmos (both bipinnatus and sulphureus species), purple coneflower, blanketflower, and Coreopsis (tickseed).

 

While the females are out busily collecting pollen and nectar from summer blooms to provision the nests for their offspring, long-horned males are famous for sleeping – often communally – in these same flowers.

Male long-horned bees sleeping communally on the stem of a Cosmos. Photo by Celeste Ets-Hokin.

Squash Bees (genus Peponapis) are close relatives of long-horned bees (genus Melissodes), and like them, are also restricted to the Americas. As their common name suggests, Peponapis species are the premiere pollinators of North American squash plants. Squash bees are definitely one of those garden guests with special dietary requirements. As specialists of squash flowers, the females will only collect pollen from varieties of these plants. Both male and female squash bees will, however, visit other flowers, including milkweed, for nectar.

 

Like long-horned bees, squash bees are ground-nesters, often making their nests close to the squash plants they depend upon for forage. So if you grow squash and want to take advantage of some highly skilled pollination services, be sure to leave enough bare, undisturbed ground close by that zucchini or pumpkin patch.

 

Female squash bees typically forage on the squash blossoms very early in the morning, while the males are often seen sleeping together in these same flowers, beginning in the afternoon. Just open a few bell-shaped golden blossoms some late summer afternoon, and you’re likely to see one or more male squash bees looking back at you. In case you have any doubt about their gender, the males have a conspicuous yellow spot on the front of their face, absent in the females.

Male squash bees (genus Peponapis) can frequently be caught napping in the squash blossoms. Males can be identified by a yellow spot on the front of their face, lacking in the females. Photo by Rollin Coville.

Sunflower, cactus or mallow bees (genus Diadasia) may not be the most common garden bees, but they are important pollinators of their various botanic partners in natural ecosystems. As their multiple common names indicate, Diadasia species are plant specialists; however, unlike the genus Peponapis, in which all the member species are squash specialists, different Diadasia species are specialists on different plants. As you might expect, some are specialists of sunflowers, others of cactus, and still others of mallows.

 

Diadasia species are limited to the Americas and North American species are found primarily in the western and southwestern United States. They are medium-sized, very hairy bees, most having a covering of pale hair over the thorax and on the legs. Coloring ranges from buff to charcoal, with some species having distinct bands of pale hair on the abdomen. Female Diadasia have pronounced scopae on their hind legs, similar to those found in long-horned females; and as seen on long-horned females, these scopae resemble shaggy, colorful legwarmers when loaded with pollen. Another well-dressed garden party guest.

 

While not a regular presence in residential gardens, like some of our other native bees, Diadasia species do occasionally make an appearance. Mallow specialists turn up to check out large stands of globemallow or bush mallow, and sunflower specialists are not uncommon in areas where these plants are cultivated.

Female Diadasia (sunflower, cactus, or mallow bees) have pronounced scopa, or pollen brushes, on their hind legs, which resemble leg-warmers when loaded with pollen. Photo by Rollin Coville.

Sunflower bees (genus Svastra) are moderately large, robust hairy bees found only in the Americas, most species being native to North America. As their common name indicates, some Svastra species are closely associated with sunflowers. Other Svastra species are specialists of cactus, and some of plants in the evening primrose family. Some Svastra species can be regularly observed on various composite flowers such as purple and yellow coneflowers.

 

Both males and females have dense golden hair on the thorax and distinct bands of alternating dark and pale hairs on the abdomen. The waxy dark brown or black integument of the abdomen sometimes shows through those portions covered with dark hair. Svastra males have noticeably hairy legs, and similar to long-horned (Melissodes) males, they are distinguished by having exceptionally long antennae. In fact, Svastra species are sometimes also referred to as long-horned bees.

Male sunflower bees (genus Svastra) have exceptionally long antennae and hairy legs. Photo by Celeste Ets-Hokin.

Svastra females are not to be outdone by the females of closely related bees, with respect to the lushness of their hind leg scopae (specialized hairs for carrying pollen). Should these beautifully attired females be compared to the nearly as well appointed females of Melissodes or Diadasia), one might be hard pressed to declare a winner in the “best accessories” category.

Female sunflower bees (genus Svastra) have particularly thick scopae, or pollen brushes, on their hind legs; when loaded with pollen, they resemble shaggy, yellow legwarmers. Photo by Rollin Coville.

Male bumble bees (genus Bombus) will begin appearing in your garden in mid- to late- summer, depending upon species. While they don’t deliberately collect pollen, due to their exceptionally fuzzy physiques, male bumble bees do transfer pollen from one flower to the next, as they visit them for nectar.

Male bumble bees are produced in late summer; they will mate with new queens, and then die by the fall. Males can often be spotted nectaring or resting on flowers. Photos by Rollin Coville.

Female workers of many bumble bee species are still active as well, collecting pollen and nectar to nourish the new crop of queens that will soon be emerging. Favorite mid- to late-summer bumble bee blooms include giant hyssop, beebalm, penstemons, sunflower and cosmos. It’s not unusual to spot a male bumble bee sleeping on the open platforms of flowers like cosmos on lazy summer afternoons. You can be fairly certain it’s a male just by virtue of this rather idle behavior, but if you need confirmation, just check his hind legs. Female bumble bees carry pollen baskets (specialized hairs called corbiculae) on their hind legs, notably absent in the males of their species.

 

Other lingering native bee guests in your garden include sweat bees, leafcutter bees, carder bees and carpenter bees. These and other midsummer bees will benefit from a diversity of mid- to late-summer blooms, such as cosmos, salvias, blanketflower, sneezeweed, catmint, mountainmint, giant hyssop, bee balm, and milkweed.

Male leafcutter bee on blanketflower. Photo by Rollin Coville.

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