Bee Mine: Pollinator Love Stories

The world of pollinators and flowers is full of love and heartbreak. For Valentine’s Day week, we’ve come up with some tales of romance to share: male honey bees that explode upon mating; hawkmoths that don’t pull their weight in the relationship; what happens when humans meddle with pollination; and more! Follow us on social media @PollinateTufts for daily updates ❤️ 

Bumble bees (Bombus impatiens) are in love with goldenrods.

Love is in the air …. and pollen – Jessie Thuma
On a crisp autumn morning, the bumble bee awakes at first light,
She suns herself at the entrance to her nest and prepares to take flight.

From her nest below the ground, she sets out through the meadow. 
What flower will she choose first? Blue or purple or yellow?

She’s an early riser, and has her pick of flowers.
But she will wait for that special bouquet that holds her in its power.

As she flies between the trees, 
She catches a sweet scent carried by the breeze.

A patch of goldenrod lit by the mid-morning sun, 
Stalks of yellow flowers enticing bees with tasty pollen.

The worker slows to land, taking stock of her workplace,
The goldenrod welcomes her, flowers opening like a warm embrace.

As she moves from plant to plant her baskets fill with pollen,
But she leaves a little behind at each plant, setting seed for future blossom.

Flowers take the shape best suited to their companion bee,
And in return bees drop pollen between plants in a pollination jubilee.

Some flowers are so perfectly shaped that only a bumble bee can reach the pollen inside,
And for these plants the worker sings a sweet buzzing song coaxing the petals to open wide.

Bumble bees are loyal and will visit the same patch of flowers for weeks on end,
Once they are enticed to try the reward, that flower becomes a bee’s best friend.

The worker leaves when she can carry no more, 
But she will be back tomorrow—that is for sure.

A honey bee drone. His huge eyes help him
find a queen to mate with, his only purpose in life! (PC: Karen Johns, Flickr)

The tragic love of a honey bee drone Isaac Weinberg
Male honey bees–known as drones–have only one purpose: reproduction. They leave the nest in the spring and summer, using their massive eyes to tirelessly search for a queen to mate with. With each hive producing hundreds of drones, but only one or two queens, most drones fail to find a mate. Eventually, these unlucky males are barred from reentering the hive, and die within a few days, cold and alone. For the lucky few that find a mate, however, love is bittersweet. The male projects his love with such force that his reproductive organs explode with a loud audible “pop,” killing the lucky bee. Thus, for the drone, Lord Tennyson’s poem becomes the eternal question; Is it better to have loved and lost, than never to have loved at all?

Orchid bees come in combinations of brilliant and iridescent colors, including green, blue, purple, orange, and yellow!  (PC: Euglossa imperialis; Flickr, USGS Bee Lab)

Orchid Bee Mine Sylvie Finn
For many, Valentine’s Day is about indulgent gift giving. Maybe you’re thinking about getting your loved one an orchid, or perhaps a fancy perfume. Well, I hate to break it to you, but you’re a little late to the game on that idea. Orchid bees are the ultimate authority on Valentine’s Day gift giving. As their name suggests, male orchid bees have a special relationship with tropical orchids (Orchidaceae). Males are attracted to the sweet and specific volatiles of orchids and use special hairs on their front legs to collect the essential oils that produce the scents. The males then store these essential oils in large modified hind legs. Each species of orchid bee has its own “recipe” of scents to combine, creating the perfect perfume to woo a mate. Once the male bee has perfected his fragrance, he presents his perfume to females in the hopes of impressing her with his ultimate Valentine’s Day gift. If he’s lucky, his perfume will be so complex and impressive that the female orchid bee will choose him as her valentine.

Tobacco hornworm moths are nocturnal pollinators. (PC: Mike Lewinski, Flickr)

You take too much in this relationship Adam Pepi
Hawkmoths are nocturnal pollinators of many plant species, including the fragrant night-opening flowers of wild tobacco. The pollination is beneficial for the tobacco plants, but sometimes the moths leave an unpleasant gift behind: their offspring. Hawkmoths deposit eggs on tobacco plants, which develop into giant caterpillars (also known as hornworms), devouring the leaves of the tobacco. This makes this a risky deal for the tobacco, but they have other options: tobacco plants that are attacked by caterpillars keep their flowers closed at night so that the hawkmoths aren’t attracted, and instead open their flowers during the day to attract hummingbirds. We can learn something from the tobacco plant this Valentine’s Day–don’t let the hawkmoth in your life hold you back.

Bicolored striped-sweat bees (Agapostemon virescens) are faithful partners of wild roses.

Roses and bees–a love story a million years in the makingNick Dorian
It wouldn’t be Valentine’s day without roses. But the roses you pick up for your honey are a far cry from the roses a bee visits in a meadow. Wild roses are simple and straightforward: five white or light pink petals open to the sky, a delicate fragrance, with pollen-laden anthers and corollas full of nectar. These flowers look and smell this way as the result of a love story with bees millions of years in the making. In contrast, ornamental roses show what happens when humans meddle with this relationship. Through careful breeding over thousands of years, we’ve managed to accentuate all the flower traits that we deem desirable, and discarded those we deem undesirable. A swirl of lipstick red petals, a hyper-intense fragrance, and no messy pollen or sticky nectar to speak of–something a bee would never recognize as her faithful lover! As a result, ornamental roses are entirely dependent on humans for reproduction. Ornamental roses may win our hearts, but it’s safe to say their long-term relationship with bees is over for good.

Agapostemon virescens: this green metallic sweat bee loves your garden

by Chloé Markovits and Nicholas Dorian

Ask a kid to draw a bee, and they will make it big and fuzzy, with black-and-yellow stripes. But did you know that not all bees look like that? One of the most common bees in eastern North America is slender, shiny, and green!

The bicolored striped-sweat bee (Agapostemon virescens) is a stunning green bee that you can find in your garden all year long. It lives mostly in the Midwestern and Northeastern United States (but with sightings from coast to coast). To help you spot one, let’s review its life cycle, flower preferences, and appearance. For a quick guide, reference Nick’s field ID tips.

A. virescens are active for most of the growing season—typically from mid-May through late October—consisting of two generations of females. In mid-May, mated females emerge from hibernation and build nests underground. They use their natal nest or dig a new hole in sparsely vegetated soils. Mulched garden beds, sandy paths, patchy lawns are suitable nesting habitat.

Agapostemon virescens live in underground communal nests.
Agapostemon virescens live in underground communal nests. Females take turns guarding the nests from unwanted intruders like parasitic flies and cuckoo bees. PC: Nicholas Dorian

Unlike the social societies of honey bees or bumble bees, Agapostemon nest in communal societies. Like apartment complexes in the human world, many females (up to 30!) will live in a single nest, but each will take care of her own offspring independently. A nest has one entrance (a hole at the surface of the ground) which is used by multiple females.

Ground-nesting bees are at risk from predators that aim to steal the nest contents. But Agapostemon has figured out a defense strategy: while some females are out foraging, at least one always stays back to guard the nest. Females take turns guarding the nest, and the presence of a guard reduces the chance of a visit from an unwanted intruder.

While out foraging, A. virescens females gather pollen and nectar. Females can be found on a wide variety of plants—from roses, to strawberries, to sunflowers—but in general have a penchant for plants in the Asteraceae family. In particular, summer-active females love collecting pollen from purple coneflower (Echinacea purpurea), cup-plant (Silphium perfoliatum), false sunflower (Heliopsis helianthoides), and lance-leaf coreopsis (Coreopsis lanceolata).

Agapostemon virescens loves asters like cup-plant.
Agapostemon virescens loves asters! Cup-plant (Silphium perfoliatum) is one of their favorite plants. PC: Nicholas Dorian

In late-July to early-August, a second generation of A. virescens emerges. This generation consists of both males and females. Males cloud around flowers waiting for the chance to mate. They are not welcome back in their natal nests, so males find places to sleep outside. Sometimes, males will sleep together in aggregate in sheltered nooks and crannies– bee slumber parties!

Fall-active females sip nectar from flowers in order to survive winter, but do not build nests or lay eggs. Look for fall-active A. virescens on asters like New England aster (Symphyotrichum novae-angliae), goldenrods (Solidago spp.), and sneezeweed (Helenium autumnale). When temperatures drop, mated females enter hibernation in their natal nests until spring, and males die.

A. virescens females can be easily identified on flowers or with photographs taken with a phone camera. Look for a metallic green thorax and black-and-white striped abdomen.  Males are trickier to distinguish from males of other Agapostemon species but in general have can ametallic green thorax and black-and-yellow abdomen.

Agapostemon virescens females can be easily identified via the combination of a metallic green thorax and a black-and-white abdomen.
Female Agapostemon virescens can be easily identified via the combination of a metallic green thorax and a black-and-white abdomen. PC: Nicholas Dorian

If you’re lucky enough to spot one, take a moment to appreciate its fascinating life cycle. Is a male darting around in search of a mate? Or a female working hard to collect pollen for her offspring? Is she hovering close to the ground? That might mean you’ve found her nest! Despite its abundance, there is still much to be learned about this bee. What soils do they like for nesting? How far do they forage? How long do females live after provisioning nests in early summer? Why do females prefer aster pollen over all others? TPI scientists are hard at work addressing some of these questions.

From where do the springtime butterflies come?

You likely learned in grade school, from Heimlich in a Bug’s Life, or from the Very Hungry Caterpillar, that every butterfly undergoes metamorphosis. For all butterflies, this phenomenon involves four distinct stages of development. An individual starts as an egg, breaks out as a caterpillar (or larva), eats leaves until it’s ready to pupate into a chrysalis, and subsequently emerges as an adult butterfly. Adults fly around to mate, feed on flower nectar, and produce the next generation. A successful butterfly not only has to make the transition from egg to larva, pupa, and eventually adult, but in New England, also has to endure six months of cold, harsh conditions. So how do such delicate creatures make it through the winter?

Well, the answer depends on which of New England’s 100+ species of butterflies we consider!

Some butterflies spend the winter as small, immobile, and defenseless eggs. Once such species is the bog copper Lycaena epixanthe which thrives in undisturbed cranberry bogs of New England such as those found on Cape Cod. Adults lay eggs on the bottom of cranberry leaves near the surface of the bog. These eggs are built to withstand not only winter freezes and thaws, but also periodic flooding. Caterpillars break out of their eggs in the spring and begin chowing down on cranberry leaves,  their favorite food. Other gossamer-wing butterflies like Coral Hairstreak Satyrium titus and Oak Hairstreak Satyrium favonius spend the winter as eggs on their favorite trees, black cherry (Prunus serotina) and oaks (Quercus spp.), respectively. Eggs are situated safely in the crevasses of the tree bark and branches, at the roots of the tree, or in the leaf litter surrounding it.

Great Spangled Fritillary. PC: Nick Dorian

The majority of butterflies spend the winter as caterpillars. Typically, these species begin feeding as caterpillars before winter to amass nutrients and fat for the long dormancy ahead. Then, when the weather cools, they find someplace safe from the elements, often underground or in the leaf litter. Other species like Viceroy Limenitis Archippus build their own houses for winter, known as hibernacula, by twirling poplar or willow leaves using silk. Not all species go about it this way though; the Great Spangled Fritillary Speyeria cybele, spends its winter as an unfed larva so that its life cycle is timed with the availability of violets.

Eastern Tiger Swallowtail. PC: Nick Dorian

Then there are species that spend the winter as a chrysalis. In this intermediary stage between caterpillar and adult, the butterfly completely reorients its body and restructures itself. The chrysalis is a very hardy life stage, which is why all swallowtail butterflies (Papilionidae) spend the winter in this form. Black swallowtails Papilio polyxenes, like many of their relatives, affix their chrysalises to a tree’s bark or branch, held in place by a thin, but strong, thread of silk. Often these dormant individuals will cryptically blend in with the branch or the leaf on which they’re placed. The Canadian tiger swallowtail Papilio canadensis, withstands the winter cold by amassing high concentrations of ethylene glycol in the chrysalis. This compound is such an effective cryoprotectant that it’s the base compound for commercially manufactured antifreeze.

Mourning Cloak. PC: Max McCarthy

Although some butterflies do overwinter as adults in New England, it’s a rare strategy. The most readily seen of these species is the Mourning cloak Nymphalis antiopa. The Mourning cloak is often the first butterfly seen in the year, coming out before snow has fully melted, and even capable of coming out on particularly warm winter days to sun. This is because it has a high concentration of glycerol, another cryoprotectant, which makes it difficult for damaging ice crystals to form in its body. The Eastern Comma Polygonia comma and Question Mark Polygonia interrogationis are two other species which also have the capacity to withstand cold New England winters. These remarkable butterflies will find crevasses in trees, beneath bark, or under rocks and buildings where they will be ready and waiting for the earliest signs of spring to emerge and mate.

And last, but not least, there are also butterflies that choose to avoid the bad weather entirely! There are only two species of migratory butterflies found in New England, which leave for the winter and come back for next year’s spring or summer. The Monarch Danaus plexippus butterfly heads south to the warmer climes of Mexico, where millions of butterflies will gather in massive aggregations in oak-pine forests. The Painted lady Vanessa cardui is another long-distance migrant, though its journey is less directed than that of the Monarch. In Europe, the species is known to embark on transcontinental migrations from the northern parts of Europe to the Sahara Desert. The details of its journey in the eastern United States remains to be known.

The diversity of overwintering approaches among butterflies demonstrates the capacity of small insects to adapt in hostile environments. When you see your first butterfly of the year, consider how they might have managed to make it outside while we’re spending time by the fireplace with hot cocoa. You also might think twice about cleaning up your leaves until the beginning of summer to give butterflies who overwinter there a chance to emerge! For other tips on supporting butterflies and other pollinators, check out our January blog post!