The Oklahoma Native Plant Society (ONPS) held its annual meeting in the Oklahoma State Student Union Saturday September 16th. Our car is still in the shop, but the rental Nissan cruised north to Stillwater without a hitch. It even has Sirius XM! Joe Roberts, ONPS president, sent out instructions to “The Chosen School. As you approach the campus, pause, take it all in, catch your breath, drive reverently along The Strip…. Continue until you see the campus and enter hallowed ground.
The Oklahoma Native Plant Society (ONPS) held its annual meeting in the Oklahoma State Student Union Saturday September 16th. Our car is still in the shop, but the rental Nissan cruised north to Stillwater without a hitch. It even has Sirius XM! Joe Roberts, ONPS president, sent out instructions to “The Chosen School. As you approach the campus, pause, take it all in, catch your breath, drive reverently along The Strip…. Continue until you see the campus and enter hallowed ground. Remain calm, speak in hushed tones and park your car…. After you find the Student Union Theater, be enlightened.
Needless to say, Joe Roberts is a true OSU man. I did pause at the ONPS table. Inside the theater people were talking and looking for places to sit in preparation to hear Heather Holm talk about “Native Bees: Their Biology and Role as Pollinators of Native Plants.” Heather is a transplanted Canadian with a background in horticulture and entomology and is a writer, designer and publisher. Her family lives in Minnesota on an almost fully restored native landscape rescued from daylilies and barberries. Her mission is to bring attention to the habits of bees in landscape management.
We see bees and take them for granted. True, busy bees must forage and collect provisions. Not all native bees are equal. There are Bumble bees, Cavity-Nesting bees, Ground-Nesting bees, and Cuckoo bees. They prefer certain flowers, nesting sites, plant communities and activity is determined by the season. Twenty thousand bee species live all over the world, 4200 species have been identified in the US and Canada, and over 400 species have been found here in Oklahoma.
Most people are familiar with the European honey bee. These are social bees that form large colonies up to 60,000 bees in one hive. The colony continues year to year and honey production is an important feature. Native bees tend to be solitary, nest in the ground or cavities in trees and other places, the adults live 2 to 6 weeks (males have shorter life spans) and they produce no honey. Their specialty is pollination. Direct competition exists between the European Honey Bee and American Native Bee based on food sources and numbers of bees. One acre of flowering plants will support one hive of honey bees. That puts pressure on the remaining habitat and impacts the native bees.
The North American native bees co-evolved with native plants. Their diet is simple: pollen provides protein and nectar supplies carbohydrates. Only the female bees collect pollen, but both sexes forage for nectar. Several species have uniquely designed pollen collecting structures. Both bumblebees and honey bees have pollen baskets, when full, resemble orange footballs. Here is where the bees mix nectar with pollen. Other bees have hairs on legs for collecting pollen. Leafcutter bees accumulate pollen on the bottom of their abdomens as they scoot across the flower.
Buzz pollination is necessary if the plants have their pollen enclosed in tubes. The pollen needs to be shaken out like salt from a salt shaker. Goldenrods, lead plant and ground cherries (Physalis sp.) are buzz pollinated. Larger bumble bees rapidly move their flight muscles, freeing pollen. The pasture rose, Rosa carolina, is one of the nectar-less plants that also need this boost. Studies have revealed bees that use buzz pollination extract more pollen in one visit than other bees in traditional mode.
The shape of the flower determines the type of bee. Open petals invite all bees, be they small or large with short or long tongues. The semi-closed flowers attract several other species, but the complex flowers entice only a few. Bumblebees are the only pollinator for the native Bottle Gentian (Gentiana andrewii), a plant with intense blue flowers. This showy plant hates heat and drought and does not grow in the southern states. Too bad for us.
Flowers have nectar guides disguised as spots, stripes or contrasting colors with ultraviolet cues to attract the pollinators. Black-eyed Susans have hidden color hues in their cells to reflect UV light in a 2 tone pattern only visible to the bees, not us! We see bright yellow flowers. Don’t forget floral fragrances….and electrical charges. Yes. Bees carry a positive charge, but flowers have a negative charge. The bees attract and pull from the flowers the pollen that attaches to their bodies. Once this happens, the flower power changes and other bees can sense that flower has been de-pollinated.
Bumble Bees are annual social nesters. The queen emerges from below ground in early spring to choose an insulated nest. These queens are large and skittery. The royal one will make a large pollen ball around which she lays few eggs. They are kept warm; the first hatchlings are always daughters. A bumblebee colony may initially have 500 female bees, but males are produced mid to late in the season along with new special females. All perish at the end except those select female queen candidates. Bumbles are generalist foragers and can travel 7 miles from home. They have long tongues, can tolerate cool temps, manipulate complex flowers and live even in the Arctic region.
Seventy percent of the native bees are solitary Ground Nesters. The male bee emerges first from the nest in the spring. The female later arrives to create her new nest. The architecture of the underground bee nest is cool. In early spring the main shaft is excavated with lateral shafts jutting from each side. Who knew? The nests are often near water, so the female waterproofs her nest using resins, oils and glandular secretions. Cellophane bees (Colletes sp.) have large abdomens and glands able to produce plastic-like secretions to line their nests. Soil deposits line the outside entry hole much like those seen with ant nests. The solitary female bee will make a small bee bread of packed pollen and lay one egg on top. The egg will hatch in one to 3 weeks. The grub-like larva munches on its bread until it changes into a pupa and enters a dormant stage, all underground. Months later, a fully grown bee will emerge into the above-ground world, ready to party.
The Cavity Nesters comprise 30% of native bees. They use holes in trees, logs on the ground, openings in the soil and other places above ground. Cavity nester tunnel walls are made of leaves. The bees combine leaf pulp, tree resins, pith or mud to create partitions to separate brood cells. Leaf cutter bees (Megachilini sp.) make leaf cylinders for nests from pieces of leaves they have cut. Leaf cutters are not picky and 54 species of plants have been found as nests. All but 6 had anti-microbial properties.
Dead growth from the previous season and the center of flower stalks are used by the pith excavators such as mason bees and small carpenter bees (Ceratina sp.). These tiny bees are the size of a grain of rice. Small bees may only fly 500 yards from their base, and tiny bees may wing it only a few yards. They are closer to you than you know. Because of their nesting habits, downed leaves and plants need to be left alone during the winter into spring. If possible, cut flower stems 15” to 18” vertically above ground. This seems to be the height bees prefer.
Cuckoo Bees have lost their hairy pollen bodies and have no pollen collecting structures. They hunt like wasps, do not build nests and prey on ground nesting bees. They watch the entrance, wait for the female to leave, hop in and lay an egg in the nearly fully provisioned brood cell. Cuckoo bees are not considered horrible. They indicate a good diversity in the bee population. I guess you might call them the canaries of the bee world.
The challenge: Flowerless landscapes. Not all is bad. Diverse bee populations have been found not only in urban landscapes but low income neighborhoods. The lower populations of people, abandoned buildings, vacant lots and lower pesticide use all contribute to higher diversity. By 2050, it is estimated 67% of the world’s population will live in urban areas.
Four bumblebee species have declined 96% the last 20 years. One species in the northwest US has become extinct. The Rusty Patched bumblebee (Bombus affinis) was listed endangered March 2017. These bumbles used to be so common along the Eastern Seaboard to the Dakotas.
What to do: Enhance and improve home gardens. Have flowers from early spring until late fall and include trees and shrubs, annuals and perennials. Mass plantings of the same plant in groups of 3, 5, 7 or more improve bee foraging. The color blocks attract the bees and the large number of flowers lower bee energy expenditure and increases the efficiency of cross-pollination. Native plants are critical workhorses for pollinating bees and are four times more attractive than the exotics. Go native.
Practice “Messy Gardening.” Leave the leaf litter, stem litter, standing dead trees and areas of bare soil. When thinking of bees, do not think of mulch. Mulch forms an impenetrable wood layer the bees can’t enter. Reduce or eliminate pesticide and fungicide use. Bees ferment the leaves with their own natural fungi to help their baby larvae digest food sources. Bees are impacted by prescribed burns and mowing. If able, only mow one third of your landscape each year.
Now, go out and help all those pollinators as they prepare for autumn, winter and next spring. Be good stewards of the land.