PLACE, PLANTS & POLLINATORS
The Hudson Valley Habitat Pollinators at Risk Our Target Pollinators Why Native Plants The Action Guide Plant List
Our Target Pollinators
New York is home to approximately 450 known pollinator species, including ants, beetles, flies, wasps, bees, butterflies, moths, hummingbirds and even bats. This guide identifies a select target group of bees, butterflies, and moths known to be at risk of population decline and even local extinction.
The 94 at-risk pollinators targeted here range from tiny but efficient sweat bees, some only 1/10" long, which spend most of their lives underground, to large and showy Sphinx moths, which alight on giant wings to pollinate wildflowers of meadows and forests. Recent research including the Empire State Native Pollinator Survey and other data from the New York State Natural Heritage Program (NYNHP) indicate that these target species are some of the most urgent conservation priorities in the Hudson Valley. Partners for Climate Action worked with scientists from NYNHP, SUNY College of Environmental Science and Forestry, University of Massachusetts at Dartmouth, and Landscape Interactions to select the species on the target list.
NYNHP assigns a “conservation status”, or S-rank, to each pollinator species, from S1 (Critically Imperiled) to S5 (Definitely Secure). Most of the species on the target list are ranked S1, S2 (Imperiled) or S3 (Vulnerable), while a few are ranked S4 (Apparently Secure) or S5 but warrant proactive conservation action. Some species on the target list are “moonshot” pollinators—species that are so rare, or haven’t been seen in our region for so long, that the potential to bring them back by restoring the plants they depend on is uncertain. However, with so much uncertainty and a lack of comprehensive data, the scientists we consulted feel they’re worth trying to save.
The target list does not include beetles, flies, or wasps, but that does not mean these insects don’t merit conservation—their populations are subject to many of the same pressures and threats as better-known bees and butterflies. Scientists believe that pollinating wasps have very similar life cycles to bees and share similar habitat needs, so conservation measures for bees will support them too. Flies and beetles are known to be significant pollinators, but as yet there are no well-established conservation criteria for them. It’s likely that restoring native plants and protecting native habitats will benefit pollinators of all stripes, including many species not on this target list.
Get to know some of the major families and species targeted by this Action Guide.
Bees
Bumblebees (Bombus species)
Bumble bees are distinctively plump and fuzzy and known for the “buzz” sound they make as they perform buzz pollination, using their bodies’ vibration to release pollen from flowers. In early spring, queen bumble bees rely on nectar from early-blooming trees such as redbud and willow trees while scouting a nest site and laying the first eggs to establish the colony. Some bumble bee species remain common, with populations secure or even increasing, such as the common eastern bumble bee (Bombus impatiens), while others are declining rapidly, like the golden northern bumble bee (Bombus fervidus).
Golden northern bumble bees are incredibly efficient pollinators, zipping from flower to flower with amazing speed.Credit: Molly Jacobson
Eastern Cucurbit Bee (Peponapis pruinosa)
This at-risk squash bee feeds its young on pollen from the squash family only—gourds, pumpkins, melons, and squash—which originated as wild plants in North and South America. Squash bees are far more efficient than honey bees at pollinating these crops. Uniquely able to fly rapidly in the dark, they start pollinating squash flowers in the early hours of the morning, before the flowers wilt. Look for male squash bees sleeping in squash flowers in the afternoon. Pesticide sensitivity and tilling practices threaten these ground-nesting bees on farms where these important pollinators forage.
An Eastern cucurbit bee pollinating a squash flower.Credit: Molly Jacobson
Mason Bees (Osmia species)
Mason bees tend to nest in hollow reeds or in pre-existing cavities in dead wood, transporting mud to their nests to construct barriers between brood cells. Bee houses, stocked with hollow bamboo stems, are often constructed in orchards to attract them. Leaving plants with hollow or soft-centered stems standing overwinter provides the best habitat for these and other cavity-nesting bees, without the risk of disease spread that bee houses may bring if not cleaned and replenished. Plants used by stem-nesting bees include joe-pye weeds (Eupatorium), mountain mints (Pycnanthemum), wild bergamot (Monarda fistulosa), elderberries (Sambucus), and swamp milkweed (Asclepias incarnata).
Mason bees are some of the most important pollinators of fruit and nut trees, both native and agricultural. Credit: Joseph Berger, Bugwood.org
Miner Bees (Andrena species)
Miner bees, so named because they excavate underground nests, are essential pollinators of many wildflowers and good food crop pollinators. Miner bees specialize in pollinating individual species of sunflowers, rockcress, toothwort, goldenrods, and other wildflowers, and several genera including dogwoods, raspberries, blueberries, and willows. Most of the specialist bees on the target pollinator list belong to this family. Miner bees are among the first bees to become active in spring, with some species emerging from their underground nests as early as mid-March; other miner bee species emerge in summer and fall.
Sunflower miner bee, a “moonshot” bee that has not been seen in the Hudson Valley for years, is one of the pollinators on our target list. Credit: Molly Jacobson
Nomad Bees (Nomada species)
The nomad bees on the target list are cleptoparasites—they lay their eggs in the underground nests of miner bees. These sleek, shiny bees, easily mistaken for wasps, don’t collect pollen or excavate nests of their own. They can be seen drinking nectar from wildflowers, or flying low, on the search for miner bee nests to invade.
Beautiful cuckoo nomad bee (Nomada bella). Credit: © Tom Murray
Oil-Collecting Bees (Macropis species)
This small group of specialist bees all rely on loosestrife (Lysimachia) species for both pollen and oil, which the flowers secrete in place of nectar. The bees use the oil to feed their young as well as to waterproof brood cells. Stands of our native loosestrife, which is different from the invasive purple loosestrife (Lythrum),are found in wet woods, swamps, and marshes, and are being displaced by development and invasive species.
Common Loosestrife Oil Bee (Macropis nuda) is disappearing from much of its range; scientists believe this bee and its host plant, fringed loosestrife (Lysimachia ciliata), will recede northward due to multiple impacts of climate change. Credit: John Klymko
Sweat Bees (Halictidae family)
The Lasioglossum genus of sweat bees are generally dark in color and very small—between 1/10" and ½" long. They generally nest in loose soils, and are highly efficient pollinators of both native flowering plants and many fruit and vegetable crops, despite their size. There are 170 different species of Lasioglossum in New York alone! Joining the dark sweat bees on the target list is one species of Halictus bee, from a different genus of sweat bees. The orange-legged furrow bee (Halictus rubicundus) lives in small social groups in warmer climates, but becomes solitary in northern climates such as ours.
Sweat bees get their name because some species will lick human sweat—they are attracted to the salt. However, they are non-aggressive. Credit: Molly Jacobson
Leafcutter Bees (Megachile species)
Leafcutter bees use their mandibles to cut out circular pieces of leaves and petals, which they use to line the inside of their nest cells. They collect pollen on special hairs on their bellies, rather than on their legs—the bright yellow pollen coating on the underside of their abdomens can help identify them.
Megachile melanophea. Credit: Molly Jacobson
Cellophane Bees (Collettes species)
Cellophane bees get their name from the clear, cellophane like material with which they line their brood cells. They extrude it from a special gland and paint it on with their forked tongues.
Blueberry cellophane bee (Colletes vallidus) Credit: Molly Jacobson
Leafcutter Cuckoo Bees (Coelyioxus species)
Leafcutter cuckoo bees, or “sharp-tailed bees,” are cleptoparasites that are closely related to their host Leafcutter bees, and even resemble them. However, they lack the hairy bellies, coated with pollen, of true leafcutter bees, instead featuring sharp prongs or tips on their abdomens, which they use to break into leafcutter bees’ brood cells to rob pollen and lay their own eggs.
Eight-toothed cuckoo leafcutter (Coelioxys octodentata). Credit: Molly Jacobson
Hudson Valley Bees: Solitary or Social?
Unlike colony-forming honey bees, the vast majority of our native bees are “solitary”—they live independently, with each female excavating or finding her own nest. Females gather pollen and nectar and bring it back to their nests, which often look like dime-sized holes in the ground, or preexisting cavities found in dead and dying wood. (Though some native bees even nest in empty snail shells, or construct nests out of mud). Females lay one or more eggs in the nest, provision each egg with a food supply of pollen and nectar, and then safely seal the egg and its food inside a brood cell, where it will develop through the larval and pupal stages before reaching adulthood and emerging the following year. Females use their nests for shelter at night and between foraging runs, while males often simply sleep on flowers.
Bumble bees are the only group of native bees which generally lead “social” lifestyles—they live together in a hive, often in an abandoned rodent burrow, tree cavity, or empty bird’s nest. Among a busy colony of 50-500 bees, only queen bees survive the winter, establishing a new colony alone the following year. Providing adequate pollen in late fall for queen bumble bees preparing for winter is a key piece of bumble bee conservation, since the survival of entire hives hinges on the survival of individuals.
Some opportunistic native bees, commonly called cuckoo bees, are “cleptoparasites.” Like cuckoo birds, who lay their eggs in other birds’ nests, they lay their eggs in other species’ brood cells. Their young hatch, kill off the hosts’ larva, and consume its food supply. These cleptoparasites cannot exist without their host species. While their life cycle may seem brutal, they are also pollinators, and coexist in balance with their hosts, adding to pollinator diversity and the resilience of the system.
Unlike honey bees and other social bees, solitary bees don’t have a honey-filled hive to protect, or a collective colony to sacrifice themselves for. As such, they are very unlikely to sting humans. Most males can’t sting at all, and females will only sting if roughly handled or stepped on.
Butterflies
As caterpillars, dreamy duskywing butterflies (Erynnis icelus) feed on deciduous tree species, then spend winter as mature caterpillars, hibernating inside leaf shelters. Credit: Bryan Reynolds / Alamy Stock Photo
Skipper Butterflies (Hesperiidae)
Many of the at-risk skippers of the Hudson Valley can be found in dry meadows, where they rely on their primary host plant, little bluestem (Schizachyrium scoparium). These smaller, thick-bodied butterflies tend to overwinter as newly hatched caterpillars right on the plants that they will feed on the following year, making fall or winter mowing a major hazard. This family includes some very rare, critically imperiled butterflies, now on the brink of local extinction, as their food plants—New Jersey tea (Ceonothus americanus) and wild lupine (Lupinus perennis) have been decimated by habitat destruction and deer browsing.
Leonard’s Skipper (Hespera leonardus), Credit: Rick & Nora Bowers/ Alamy Stock Photo
Fun Fact: Some skippers fold or fasten leaves together with webbing to make a protective “tent” for their caterpillars to shelter inside. They can shoot their droppings, projectile style, far away from the tent to avoid attracting predators.
Emperor Butterflies (Apaturinae)
The two emperor butterflies of the Hudson Valley are both specialists—their caterpillars feed only on the leaves of Northern hackberry trees (Celtis occidentalis). Both overwinter as caterpillars, sheltering under leaf litter at the base of hackberry trees. Ditching the leaf blower and leaving leaf litter in place, particularly under hackberry trees, is a great way to protect these butterflies. Climate change is making emperor butterflies more vulnerable, as cold Hudson Valley winters without the insulation of snow cover threaten their winter survival.
Hackberry emperor Caption: Hackberry emperor (Asterocampa celtis),Credit: Whitney Cranshaw, Colorado State University, Bugwood.org
Fritillary Butterflies (Argynninae)
These small, colorful butterflies are often seen flying low to the ground in meadows and grasslands. The caterpillars of all three fritillary species on the target list feed exclusively on violet leaves (Viola species).
Meadow Fritillary Boloria bellona, Rick & Nora Bowers / Alamy Stock Photo
Metalmark Butterflies (Riodininae species)
Listed as critically imperiled in New York (S1), northern metalmark butterflies are on the brink of disappearing from their range in the state, with some of the only state sightings in Dutchess County. This specialist needs roundleaf ragwort (Packera obovata) to complete its life cycle. Nectar from July-blooming butterfly weed (Asclepias tuberosa) is also a critical food source for adult metalmarks of the Hudson Valley.
Rare northern metalmarks (Calephelis borealis) are one of the only butterfly species that rest on the undersides of leaves, Bryan Reynolds /Alamy Stock Photo
Hairstreak butterflies (Lycaenidae)
Listed as critically imperiled in New York (S1), northern metalmark butterflies are on the brink of disappearing from their range in the state, with some of the only state sightings in Dutchess County. This specialist needs roundleaf ragwort (Packera obovata) to complete its life cycle. Nectar from July-blooming butterfly weed (Asclepias tuberosa) is also a critical food source for adult metalmarks of the Hudson Valley.
Juniper hairstreak (Callophrys gryneus) adult. Credit: Patricia M. Ciesla, Forest Health Management International, Bugwood.org
Caterpillars of juniper hairstreak (Callophrys gryneus) butterflies forage on the leaves of Eastern red cedar. These trees are becoming more scarce as the open fields where they thrive in the Hudson Valley are being developed, or transitioning to mature forest. Connecticut Agricultural Experiment Station, Bugwood.org
Elfin butterflies (Lycaenidae)
Frosted elfin butterflies are extremely vulnerable, with only a handful of local populations left in New York. Deer overpopulation strongly impacts them, as deer will sometimes consume entire stands of their host plants, and the eggs and larvae on the plants along with them, eliminating a whole population. Related but more stable, brown elfin butterflies (Callophrys augustus) feed on several heath family (Ericaceae) plants, such as sugar huckleberry (Vaccinium vacillans) and Labrador tea (Rhododendron groenlandicum). They hibernate in the chrysalis phase, in leaf litter at the base of their host plants.
Specialist frosted elfin butterflies (Callophrys irus) have two distinct populations; caterpillars in the upper Hudson Valley feed on wild lupine (Lupinus perennis) only, while populations in the lower Hudson Valley forage on wild indigo (Baptisia species). Bryan Reynolds / Alamy Stock Photo
Moths
Less is known about the life cycle and conservation status of moths. Many of the moths known to be threatened are large charismatic species, but many more are likely at risk, with further research needed.
Sphinx moths (Sphingidae)
The family of sphinx or “hawk” moths include some of the most exquisite-looking and largest moths in the world, and sport the longest tongues of any pollinator, up to 11" in length. The twelve at-risk moths on the target list are all sphinx moths. Though most are active at night, you may be lucky enough to spot a beautiful sphinx moth resting during the day.
The huckleberry sphinx moth (Paonias astylus) lays its eggs on blueberry and huckleberry plants, (c) Andrew Block
Track your Success
It’s exciting to recognize pollinators as they reappear in restored habitats. Apps and guidebooks can help you identify pollinators at your site. Investing in a cheap clip-on macro lens for a smartphone camera can enable you to take close-up photos of pollinators, which can be helpful for identification. You can contribute meaningfully to pollinator research by logging your sightings in citizen science projects on platforms such as iNaturalist.
Some of our favorite resources include:
ID Apps: InsectIdentification, Beecology, PictureInsect, Leps by Fieldguide
ID Guidebooks: NWF Guide to Insects and Spiders of North America, Pollinators of Native Plant; Caterpillars of North America: A Guide to Identification and Natural History
ID Websites: BugGuide
Citizen Science Opportunities: Bumble Bee Watch, iNaturalist, MonarchWatch, National Moth Week, BAMONA (Butterflies and Moths of North America Identification and Citizen Science)
Local Field Excursions: Look for pollinator walks with the Cary Institute, Farmscape Ecology Project, Pollinator Patrol Club (family-focused), and other opportunities to learn from local experts
When to Watch: Pollinators are most active during our warmer months—warmer days and nights make their preferred foods available and help keep their muscles warmed up for flight. A sunny mid-afternoon in mid- or late summer is the best time to observe a diversity of species. On chillier mornings and evenings, you may spy male bumble bees, which often sleep on flowers in late summer and are very still and docile in cold temperatures. In early spring, the large bumble bees buzzing near the ground are most likely queens just emerging from their winter hibernation to forage on the year’s first flowers. You may also never have the chance to see some of the pollinators you work to protect—many of these moths and even a few bees are active before sunrise or only at night, and some native bees are too tiny for casual observation.