Summer recap: a glimpse at pollinator fieldwork

The growing season is a busy time for pollinator scientists. Here’s what members of TPI got up to this summer! 

Cellophane bees

Nick, Leslie, and Lydia dug into the secret lives of solitary bees in New Hampshire. They want to know “where does a bee fly in her life?” To answer this, they caught and painted blueberry cellophane bees at nests to identify unique individuals. Then, they surveyed flowers and nesting areas to track daily movements. They painted over 1200 bees!

Bumble bees

Jessie, Lauren and Liana planted hundreds of goldenrod and sunflowers to find out how our growing practices affect the food available to bumble bees — an important native bee that pollinates tomatoes, peppers, melons and more. Bumble bees (like other bees) eat pollen and nectar, and need abundant, high-quality food to fly, pollinate, and raise new bees. They want to know how fertilizer and drought change plant growth, the number of flowers they produce, and the nutrient breakdown of their pollen and nectar. They spent the early summer digging, planting, weeding, and watering and ran a choice experiment to find out which plants bumble bees prefer to visit.

Baltimore checkerspots

Brendan spent the spring and summer studying the impact of the Junonia coenia Densovirus on Baltimore checkerspot population dynamics. He set up an enclosed experiment that exposes caterpillars to a gradient of viral loads and monitored the impact on their survival and reproduction. Later in the summer he continued field sampling for a project that is using a metagenomic approach to investigate whether Lepidopteran viruses are shared between co-occurring caterpillar species. This will help him understand the likelihood of disease spillover impacting species of conservation interest.

Honey bees

Isaac and Greta studied the effect that temperature stress has on the way honey bees arrange their comb stores. They hope to learn how increasing global temperatures will affect the structure of honey bee colonies.

Milkweed visitors

Atticus, Karen, and Kristina are looking at pollinator usage of milkweed in urban environments. Atticus and Karen observed monarch egg-laying behavior on milkweed, the monarch butterfly’s host plant, to see if it changes depending on surrounding landscape contexts, such as differing neighborhood flower garden densities. Kristina looked at milkweed flower visitors to see how visitation rates and species richness are affected by flower garden densities. You may have seen their pots at various park locations in Medford and Somerville!

Sweat bees

Chloé, Nick, and Aviel studied sweat bee (Agapostemon virescens) movement on Tufts’ campus. They want to know whether roads act as barriers to foraging bees. To answer this, they set up squares of four pots of coneflower bisected by roads at three sites on campus. At these sites, they caught and painted bees to identify unique individuals and recorded ongoing traffic.

Yellow-faced bumble bees

Across the country in California, Sylvie is studying the difference in life cycle patterns of Bombus vosnesenskii, the yellow faced bumble bee. Sylvie is interested in how life cycle timing of this bumble bee varies across its range. In the Sierras, B. vosnesenskii displays the characteristic timing of bumble bees – a queen emerges in spring, a colony grows over the summer with female workers, and at the end of the summer the queen stops producing workers and starts producing new queens and males. Then, the mated female queens overwinter underground! Sylvie is getting to discover firsthand the timing of Bombus vosnesenskii life cycle on the coast–and how it compares to timing in the mountains–since it has not yet been characterized! 

Pipevine swallowtails

James and Kaitlyn mated adult pipevine swallowtails and tested how growth rates in their offspring may be affected by differences in ambient temperature. These females laid eggs on Dutchman’s pipe and they collected those eggs to put in different thermal treatments. They will monitor those larvae until they’re ready to become adults themselves.

Monarch butterflies

Also in California, Emily studied monarch butterflies in urban gardens in the San Francisco Bay Area. Most people know monarchs for their impressive yearly migrations. Recently, however, year-round breeding ‘resident’ monarchs have also established in coastal cities in Northern California. These residents are associated with non-native milkweeds – namely Tropical Milkweed (Asclepias curassavica), which do not die off in the winter as the native species do and therefore provide breeding habitat throughout the year. We don’t yet know yet how resident and migratory monarchs interact with one another in urban gardens, and what the consequences of these interactions may be. In her research, Emily hopes to understand whether the resident monarchs in urban gardens are a population that is independent of the migratory one, or whether the presence of residents and their non-native host plants are contributing to overall monarch declines in the West.

The 5 best ways to make your yard pollinator friendly

by Atticus Murphy

Planting a pollinator garden is all the rage these days, but if you’ve never gardened before, it may seem like a daunting task. Don’t worry, it doesn’t have to be complicated! You can support pollinators in your yard by taking several easy and important actions. Tufts Pollinator Initiative has distilled it down to the 5 most important actions you can take today!

1. Plant a diverse set of flowering plants

Diversifying the flowers in your garden is the best way to support the most types of pollinators. Shoot for diversity on all levels: color, flower shape, size, and, most importantly, bloom time. Each pollinator species might only be active for a few weeks and visit a small number of plants, so adding flower diversity throughout the year will almost always boost your yard’s pollinator diversity (and give you blooms year round!). A good place to start? TPI’s top 10 flowers for bees! 

Diversity begets diversity: we’ve planted over 15 flowering species at our campus gardens and seen over 115 species of insect pollinators!

2. Add woody plants like trees and shrubs

Native trees and shrubs make excellent additions to pollinator gardens because they provide resources that herbaceous, perennial flowers often don’t. For instance: many native trees and shrubs bloom early in spring, at a time when few other plants are blooming on the landscape. In addition, trees and shrubs provide homes for solitary bees and many butterflies depend on tree leaves to complete their life cycles. As a bonus, trees and shrubs require very little maintenance after their first few years and provide shade for decades! To help you pick, check out TPI’s top 10 trees and shrubs for bees.

Unequal cellophane bees (Colletes inaequalis) depend on pollen and nectar from early-blooming red maple trees to complete their life cycles.

3. Grow native plants

To support our native pollinators, grow native plants. Our native pollinators have been in relationships with native plants for thousands of years, and sometimes have evolved such a picky diet that only one or a few native plant hosts will do. Avoid non-native ornamental plants (esp. doubled cultivars) like petunias and impatiens–they either offer unsuitable food resources, or have been bred to offer no pollen and nectar whatsoever. Compared to traditional ornamental plants, native plants can survive is less than ideal soils and periods of droughts, while still filling your garden with bursts of color. Pick up your locally-grown native plants at TPI’s summer plant sale!

fall bees fueling up on new england aster before winter
Native bees love native flowers like New England aster.

4. Minimize herbicide and insecticide use

It’s simple: to keep insect pollinators around, don’t apply pesticides. Herbicides kill the flowers that pollinators use for food. Leaving weedy flowers (“weeds”) to bloom creates abundant and diverse resources for pollinators. And insecticides like neonicotinoids are deadly for pollinators: remember, anything that kills a mosquito almost certainly kills a bee. Even if you apply these chemicals to a separate area of your yard, they have a high potential of running off into the surrounding pollinator friendly areas. Stick to hand weeding problem plants whenever possible and try handling pesky insects in chemical-free ways like limiting standing water or having nests removed.

5. Mow remaining lawn infrequently

Conventional turf lawns are fun play spaces, but monocultures of grass do not support pollinators, so it’s always best to limit the amount of lawn on your property. For any lawn that you keep around, one of the most impactful things you can do is to mow as little as possible. Even going from mowing weekly to mowing every other week leads to dramatic increases in the number of pollinators and flowers found in lawns. You don’t need to let the lawn look truly wild to achieve big benefits either! Leaving a margin of unmowed grass around the edge can provide valuable nesting habitat for bees and low-growing flowers like white clover.

By mowing your lawn less frequently, you can support native pollinators like bicolored striped sweat bees Agapostemon virescens!

Following these simple steps can help you take big strides towards making your patch of the urban landscape a haven for pollinators. One of the most rewarding things about implementing steps like these is that you are nearly guaranteed to see returns after just a small amount of investment–if you plant it, the bees, butterflies, wasps, and hover flies really will come. Happy gardening!

To learn more, check out our publication on pollinator gardening produced in collaboration with Tufts CREATE Climate Solutions.

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.