Japanese Knotweed (Fallopia japonica) was introduced from Japan in the 1800’s as an ornamental; it was widely cultivated, escaped and is now well established throughout the Northeast. The World Conservation Union lists Japanese Knotweed among the top 100 worst invasive plants. Its dense canopy and rapid spread through underground rhizomes make it a formidable threat to native plants and the animals that depend on them.
There are some redeeming qualities to this invasive plant, however. In addition to goldenrod and asters, Japanese Knotweed is a crucial source of late-season nectar and pollen. At this time of year, when Japanese Knotweed flowers, you can almost locate a stand using just your ears, the buzzing of honey bees gathering the last of their winter food supply from the thousands of tiny flowers is so loud. A wide variety of insects can be found on this member of the Buckwheat family eating leaves, foraging for nectar and pollen, and preying on the former. A recent survey revealed honey bees, bumble bees, ladybug beetles, flies, hornets, yellow jackets, stink bugs and tussock caterpillars, to name just a few.
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Miterwort (Mitella diphylla), also called Bishop’s Cap, is named for the resemblance of its two-peaked fruits to the hats (known as miters) worn by bishops of the Roman Catholic Church. This spring wildflower produces miniature five-pointed snowflake flowers that beg to be examined with a hand lens.
Gnats, small bees and syrphid flies all seek out Miterwort for its nectar. Because its nectaries are located just below the stamens, the flower is pollinated by the mouthparts of the pollinators which brush against the stamens when collecting nectar and the inadvertently-gathered pollen is transported to other Miterworts. Predators such as the Goldenrod Crab Spider (pictured) know that potential meals are plentiful near these delicate flowers.
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With frost just a whisper away, and in some areas not even that, there are still hardy plants, many in the Composite family (goldenrods, asters, thistles, Queen Anne’s Lace, Yarrow), which defy the odds and optimistically send forth blossoms on the off chance that there are still pollinators on the wing. Fortunately for them, bumblebees can and do fly at much cooler temperatures than honeybees and other pollinators. When food is plentiful and outside temperatures fall below 50°F., bumblebees generally stay inside their nest and live off their stores. At times when food is scarce or stores are low, they will forage when the outside temperature is as low as 43°F. (In severe conditions they have even been known to vary their flying height to and from the nest to take advantage of any temperature differences.) Locally, Tri-colored Bumblebees (Bombus ternarius) have a near monopoly on the last vestiges of nectar and pollen (see photo).
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Grass of Parnassus, Parnassia glauca, (also known as Bog- Star) was named after Mount Parnassus in central Greece. It is not a type of grass, but rather, belongs to the family Celastraceae and can be found growing in fens, bogs and swamps. The striking green lines on its petals guide flies, bees and other pollinating insects to the flower’s supply of nectar.
The structure of Grass of Parnassus’s flower is not typical. In between its five functioning stamens and five petals there is a whorl of five sterile stamens, each of which is three-pronged. The spherical tip of each prong mimics a glistening droplet of nectar. These stamens do not actually produce any nectar – they are there purely to attract pollinators. The actual nectar is located near the base of these false, or sterile, stamens. Only one of the five true stamens in the flower is active at any one time, with each producing pollen on average once every 24 hours.
Goldenrod is one of the most important flowering plants for honeybees because it is a prolific producer of nectar and pollen late in the year. Blooming in the late summer and fall, this bright yellow-flowered composite provides nectar for the bees to build up stores of honey for winter. (Goldenrod honey is dark amber and strong tasting.) Goldenrod also provides pollen to help stimulate the colony to produce brood late into the fall. The pollen adds considerable amounts of protein, fats, and minerals to the diet of the late-season bees, helping ensure that they will have food throughout the winter.
The month of June can’t go by without a mention of Showy Lady’s Slippers. Just fifty years ago, this orchid could be found over most of the Northeast. Habitat loss and an exploding deer population are considered major factors in Showy Lady’s Slipper’s decline, making it endangered or on the verge of extinction in many areas. Although rare, it is still locally abundant, particularly in fens (peat wetlands that get their water from rainfall and surface water).
As with Pink and Yellow Lady’s Slippers, one of Showy Lady’s Slipper’s three petals is greatly modified into a large inflated pouch called the labellum . (The pouch’s color can vary widely from year to year, depending on the ambient temperature. Cooler conditions appear to produce more intense color.) The petals on either side of the pouch attract pollinators with an alluring odor, but the insects that enter into the pouch are in for a disappointment, as lady’s slippers produce little or no nectar. The structure and positioning of the pistil and stamens are such that they encourage cross-pollination to take place, which is crucial, as lady’s slippers rarely self-pollinate.
Ragged Robin, Lychnis flos-cuculi, is native to Europe and has become so abundant in northern United States that it borders on being considered an invasive plant. Found usually in wet areas such as marshes, fens and wet meadows, this perennial can cover an area as large as an acre. When flowering, Ragged Robin is very noticeable — not only to humans, but also to the many insects that pollinate it. Bees and butterflies, especially, flock to stands of this plant in order to obtain its nectar and white pollen. (If you suck the base of the flower, you will soon detect the sweetness that attracts pollinators.)
Thank you for all your guesses, a vast majority of which were right on the mark. Bloodroot, Sanguinaria canadensis, is one of the first spring ephemerals to bloom. On sunny days its petals are open wide, closing at night when the temperature drops and on cloudy, rainy days (when pollinating insects are less apt to visit). Only pollen is produced by Bloodroot – no nectar. Even so, insects, especially mining bees, visit and collect pollen, and in the process often pollinate the flower.
The methods which Bloodroot employs in order to become pollinated are impressive, to say the least. While cross-pollination is preferable, self-pollination is better than nothing. To limit self-pollination, the female stigma becomes receptive before the male anthers of the same flower produce pollen. Furthermore, during the first few days of the flower opening, the anthers bend downward toward the outside of the flower, away from the receptive stigma, where they are easily accessible to insects. If insect pollination doesn’t take place by the third day of flowering, however, the anthers bend inward, contacting the stigma and self-pollinating the flower.
Most bumblebees, unlike honeybees, die in the fall. Only the young, fertilized bumblebee queens overwinter. When they emerge early in the spring, each must start a new colony, with no help from worker bees. The queen builds a ball of moss, hair or grass, often in an abandoned rodent nest or small cavity. Within this ball the queen builds a wax honey pot, and provisions it with nectar from early-blooming flowers. Next, she collects pollen and forms it into a mound on the floor of her nest. She then lays eggs in the pile of pollen, and coats it with wax secreted from her body.
The queen bumblebee keeps her eggs warm by sitting on the pollen mound, and by shivering her muscles, raising her body temperature to between 98° F. and 102° F. For nourishment, she consumes honey from her wax pot, which is positioned within her reach. In four days, the eggs, all of which will become female workers, hatch. The bumblebee queen continues her maternal care, foraging for pollen and nectar to feed to her larvae until they pupate. After this first brood emerges as adult bumblebees the queen concentrates her efforts on laying eggs. Unfertilized female worker bees raise the larvae and the colony swells in number. At the end of summer, new queens (females) and males are produced in order to allow the colony to reproduce. After the new queens mate and become fertilized, the males all die, along with the female worker bees. The queen then seeks shelter for the winter. (Photo: Tri-colored Bumblebee queen collecting Trailing Arbutus nectar or pollen)
Winterberry (Ilex verticilatta) fruits mature in late summer and early fall, but they are much more evident now that most of the leaves have fallen off this deciduous member of the Holly family. Because these shrubs are dioecious (male and female flowers appear on separate plants), only the female shrubs bear fruit. The bright red berries often persist through the winter and provide cedar waxwings, bluebirds and robins with food long after most fruit has disappeared.
At a time of year when nectar and pollen sources are few and far between, New England Aster provides many species of bees with food. This composite seems designed specifically for easy pollination. Its open, wide flower shape provides a flat surface for insects to land on, and because the nectar and pollen are not hidden deep inside the flowers, both long- and short-tongue bee species can easily access them. Unlike honeybees, bumblebees do not have a large store of honey in their nests, so they need pollen and nectar throughout the season. Thus, the few flowers such as New England Aster that blossom as late as October are visited frequently and in large numbers. (Only the queen bumblebee overwinters, but the workers continue collecting nectar and pollen up until they die in late fall.)
New England Aster flowers close at night, when there are fewer pollinating insects flying. If an unusually cool period arrives during the time when New England Aster is blooming, the blossoms also close. Although it may seem that the aster is losing pollination opportunities during a cold day, bees are not very active in cool weather.
The combination of Bottle Gentian’s (Gentiana clausa) blossoms’ brilliant purple/blue color, their shape, and the difficulty insects have in prying open the bottle neck their petals form, make them a highlight of every September. Getting inside their flowers is a monumental task, and one that few insects, other than fairly large species of bumblebees, attempt — much less accomplish. It takes several seconds of pushing, shoving and cramming to get their head through the miniscule opening at the top of the blossom. Eventually their body follows, sliding down into the flower. While the whole bee sometimes disappears, it’s more usual to see their hind legs poking out of the flower while they lap up nectar. Not only are bumblebees strong, but their tongues (see insert) are long enough to reach the copious amount of sugar-laden nectar that awaits them inside the flower.
The Clymene Moth, Haploa clymene, is noted for the striking upside-down cross pattern on its forewings. Because of this design, some people refer to it as the “Crusader Moth.” A member of the Tiger Moth family (as is the Woolly Bear/Isabella Tiger Moth), the Clymene Moth can be seen flying day or night. Typically they inhabit deciduous forests and fields adjacent to them where the black, bristly larvae feed on a wide variety of plants, including willows, oaks, and members of the Aster family. In contrast to its white forewings, the Clymene Moth’s hind pair of wings is bright yellow. Its long proboscis allows it to reach deep inside the nectar-bearing hoods of Common Milkweed.
Blue Vervain (Verbena hastata) is a fairly tall (2 – 5 feet) flowering plant found in wet meadows. Its flower spikes branch upwards like the arms of a candelabra, and each has a ring of blue-purple flowers. The flowers at the bottom of the spike bloom first, and the ring of flowers advances upwards to the tips of the spike. Although Blue Vervain flowers have no scent, both long- and short-tongued bees are attracted to it primarily for its nectar, but also for its pollen. While Verbena Moth caterpillars feed on the foliage, most mammalian herbivores avoid eating this plant because of the bitter leaves. Various songbirds occasionally eat the seeds, including Cardinals, Swamp Sparrows, Field Sparrows, Song Sparrows, and Dark-eyed Juncos.
Even if it weren’t such a beautiful and vibrantly-colored flower, Viper’s Bugloss, Echium vulgare, would be notable just for its name. “Bugloss” is of Greek origin, from a word signifying an ox’s tongue, and alludes to the roughness and shape of the plant’s leaves. Some say the dead flower-head and/or seed resemble a snake, and in the 1600’s this plant provided a popular cure for snake bites. A long-flowering (all summer and into the fall) member of the Boraginaceae family, Viper’s Bugloss is particularly popular with bees. It produces nectar throughout the day, unlike most plants which produce nectar for a short period of time. With an unlimited supply of Viper’s Bugloss, honeybees can collect between 12 and 20 pounds of nectar a day.
For years scientists assumed that hummingbirds passively extracted nectar from flowers with their tongue through capillary action, but it turns out that this is not the case. A hummingbird’s forked tongue (which is twice as long as its beak) is lined with hair-like extensions or fringes called lamellae. When it is inserted into a flower and immersed in fluid, the tongue separates and the lamellae extend outwards so that open grooves (between the lamellae) lay flat. As the hummingbird pulls its tongue into its mouth, the forked tips come together and the lamellae roll inward, trapping the nectar within the tongue until it is swallowed by the hummingbird. No output of energy is necessary on the part of the bird – this process is automatic, takes all of 1/20th of a second, and occurs thousands of times a day. (Thanks to Ginny Barlow for Ruby-throated Hummingbird photo op.)
A walk in deciduous woodlands at this time of year could result in the sighting of several species of orchids, one of which, Showy Orchis (Galearis spectabili), has a stalk of several flowers which typically bear lavender hoods (one variant is white). Potential pollinators, most of which are long-tongued bumblebees, butterflies, moths and bees, land on a white petal below the hood which acts as a “landing pad.” The insect next heads for the tip of the nectar-filled spur located at the back of the flower. In getting there it brushes against, and often picks up, packets of pollen (pollinia) before moving on to the next blossom, where cross-pollination ideally takes place. (Thanks to Ginny Barlow for photo op.)
Ninety percent of bees are solitary – the fertile females create their own cells and feed their own young, with no help from a colony of worker bees. They often nest underground, rarely sting and are excellent pollinators, even though they don’t store honey. Colletes inaequalis, a type of Plasterer Bee also known as the “Polyester Bee,” and “Unequal Cellophane Bee,” is a solitary bee. It derives its common names from the practice of lining its underground nest cells with a secretion that, when it dries, forms a smooth, cellophane/polyester-like lining. This cell holds one egg suspended above a collection of pollen and nectar on which the larva will feed. The Unequal Cellophane Bee is crepuscular, which can be deduced by the large size of its eyes. It is one of the earliest species to become active in the spring, sometime between March and May, when adults bees emerge from underground chambers off a vertical tunnel dug by their mother last spring. (Why it is called an “Unequal” Cellophane Bee I have not been able to determine.)
Trailing Arbutus (Epigaea repens) is said to have heralded spring to the winter-weary Pilgrims in 1621 and thus is known as “Mayflower” by many. (It is also the Massachusetts state flower.) Creeping along the ground where the soil is typically quite acidic are Trailing Arbutus’s hairy, woody stems bearing evergreen, aromatic leaves that are present year round. Only in the early spring are we treated to its fragrant pink flowers, often nestled under these leathery leaves. Abundant nectar is found by overwintering bumblebee queens that are attracted to Trailing Arbutus’s indescribably delicate and sweet-smelling scent.
Even though they are not rare and they are not especially known for their beauty, the dandelion-like flowers of Coltsfoot beckon like no others. To humans, the brilliant yellow petals of this member of the Aster family are a bright beacon in the relatively drab brown world revealed after the snow melts. But they are an even more compelling sight for bees at this time of year, for these flowers are a very early source of nectar in the spring, when there are few other wildflowers blooming.
Bottle Gentian, Gentiana andrewsii, is one of our latest blooming wildflowers, and one of our most beautiful. Because its petals are closed so tightly, only bumblebees (pictured) and a few other insects have the strength to push their way inside the flower to reach Bottle Gentian’s sugar-laden nectar.
Like many other flowers, Bottle Gentian times the maturation of its reproductive parts to discourage self-pollination. Male pollen-bearing stamens mature first, and by the time the female pistil is mature, the stamens have gone by so the flower’s pistil can’t receive its own pollen (see central pistil surrounded by withered stamens in insert).
Nectar from flowers and sugar from running sap (especially at Yellow-bellied Sapsucker holes) or overripe fruit provide most, but not all, of the nutrition that butterflies need. The males of some species will also drink at muddy puddles or damp earth for mineral salts and on scat or animal carcasses to get amino acids and other vital nutrients. This added nutrition is needed for them to generate spermatophores, the packets of sperm and nutrients that are transferred to the female during mating. (Photo is of a White Admiral, Limenitis arthemis arthemis, feeding on blackberry seed-laden Raccoon scat.)