Pollination is defined as the plant fertilization process in which pollen is transferred from the anthers of a flower to the stigma of the same or another flower. Pollination occurs in a number of ways including via wind or gravity, but is also commonly carried out through the activities of various organisms that move the pollen while conducting their own important business of surviving. According to the USDA, there are about 200,000 organisms worldwide that act as pollinators. With only about 1,000 of them being vertebrates (mammals, birds, etc.) the rest are invertebrates with the majority of those being insects. The majority of the pollinator insects are bees which is why we typically think of bees when we think of pollinators.
While the last 10 years or so have seen disparaging news reports of declines in bee populations, recent months have seen news reports of rising bee populations. While this is true, it primarily applies to honeybees. Honeybee populations are easier to gauge because they are managed by beekeepers. At Winnie Palmer Nature Reserve, we have been so successful with our beehives that they survived the winter and have recently split off to form new hives. Other beekeepers we work with have also exhibited increased success in their beekeeping. While the increased success of honeybees is wonderful news, it’s also important to remember that honeybees are an introduced bee species. Other species of pollinators such as native bees as well as butterflies, moths, and more still face declining populations due to threats such as habitat loss, pesticide, and disease.
As part of our series of ’10 Fun Facts on the 10th of Each Month’ in celebration of our 10th year open to the public, here is a list of 10 pollinator organisms that are not honeybees as well as how you can support their habitats in your yard.
Our list starts with 4 types of bees found in Pennsylvania. Bees tend to get a bad wrap because of the potential for being stung. Most stings that are blamed on bees, however, are actually the work of wasps or hornets such as yellow jackets. Bees are usually very docile and the chances of being stung by one are low. Native Pennsylvania bees can be supported not only by planting native plants that they are attracted to but also by conserving their natural habitat, reducing pesticide use, offering water supply, and offering habitat. Pennsylvania has over 300 species of bees, many of which fall under the following categories:
1. Bumblebees (Bombus spp.)
Bumblebees utilize what’s known as ‘buzz pollination’ which means that they vibrate the pollen off of the anthers of the flower. They tend to be larger and ‘fuzzier’ than honeybees and have smaller colonies, also centered around a queen. There are dozens of species in Pennsylvania and depending on the species, they could be ground nesters, surface nesters, or nest in hollow logs. The tongue length of each bumblebee also varies and the types of flowers that attract them will depend on the tongue length. Biologists believe this morphological design keeps bumblebee species from competing with each other for
resources. Bumblebee species in Pennsylvania include the Common Eastern Bumblebee (Bombus impatiens) and the Confusing Bumblebee (Bombus perplexus). You can help bumblebee species by planting cover crops on your lawn such as clover, hairy vetch, and buckwheat. Allowing these lawn plants to bloom occasionally provides a food source for bumblebees. Additionally, planting certain native plant species in your garden will also attract them. Visit http://extension.psu.edu/publications/uf023/view for a list of suitable native plants as well as when they bloom.
2. Mason bees (Osmia spp.)
Mason bees are named for their habit of nesting in established holes and then using mud to cover the nest. They are solitary bees and therefore much more docile than most other bees as they do not have a colony to protect. While offering certain native plants will attract them, you’re more likely to attract them by providing habitat for them. Your habitat can be as fancy and artistic as the ‘bug hotel’ at WPNR, created by Eagle Scout Christopher Weossner, or it could be as simple as a piece of wood with some holes drilled into it. Visit http://extension.psu.edu/plants/gardening/news/2015/create-a-mason-bee-habitat-1 for more information.
3. Sweat bees (Halictus spp.)
There are several types of sweat bees in Pennsylvania. Some, such as the metallic green bees, don’t much resemble what we typically think of as ‘bees’ and therefore are sometimes mistaken for flies. Sweat bees are short tongued, usually solitary, and some are attracted to human sweat. Although they’re typically found around the same plants that attract other types of bees, they are also partial to crops such as alfalfa, cane berries, and onions.
4. Squash bees (Peponapsis pruinosa)
Squash bees are named for their preference for squash plants such as cucumber, melon, and, of course, squash. Solitary ground nesters, they will typically visit flowers in temperatures and light conditions that other pollinators find unsuitable. If your vegetable garden contains squash species, you’re likely to find these docile bees.
Butterflies & Moths (Order Lepidoptera)
Lepidoptera means ‘scale wing’ in Greek. The name comes from the covering of a scaly material on their wings in the adult form. The order consists of moths and butterflies which start out as a larva that we call caterpillar before undergoing metamorphoses in a chrysalis (butterflies) or a cocoon (moths). The adults typically lay eggs on a particular plant that will be fed by the caterpillars. Unlike bees, lepidopterans don’t actively seek pollen, just the nectar. But they still pollinate while feeding as pollen gets stuck to their bodies while they feed.The adults feed on flower nectar with a long, protruding mouth piece called a proboscis. When not in use, the proboscis is kept close to the head in a spiral shape. The following are examples of moths and butterflies that are found in Pennsylvania:
5. Hummingbird Moth (Hemaris sp.)
Hummingbird moths are named due to their strong resemblance to hummingbirds. They hover and move very similarly to a hummingbird but upon closer inspection can be seen feeding on nectar with the proboscis and they lack feathers. Their caterpillars prefer honeysuckle but adults will feed on a variety of flowers. They’re most active from late spring to early fall and can be seen feeding during daylight hours as well as night.
6. Eastern Tiger Swallowtail (Papilio glaucus)
Swallowtails are a commonly found butterfly in Pennsylvania and one of the most common is the eastern tiger swallowtail butterfly. It’s one of the largest butterflies, making it easy to spot. These large beauties are pretty easy to attract with an abundance of flowers in your garden.
7. Ruby Throated Hummingbird (Archilochus colubris)
While there are multiple species of bird that feed on nectar and/or act as pollinators, the most common one in Pennsylvania is the ruby throated hummingbird. Although 2 other species of hummingbird will fly through our state, this species is the only one that breeds and nests in North America. Of course they fly straight and fast but they can stop quickly, hover, and adjust up and down, side to side, and backwards. Hummingbirds prefer tube shaped flowers so plants like petunias, bee balm, cardinal flower, gardenias, and yarrow will attract them.
Wasps are in the same order, Hymenoptera, as bees. Some species of wasp, however, can be a bit more aggressive than bees and the sting of many is more painful. That sting, however, actually serves several functions. For starters, it serves as a defense mechanism. Wasp stingers are not barbed, like bees are. Therefore, they can sting multiple times and will do so when defending themselves and/or their colonies. The second function of the wasp stinger is for hunting purposes. Wasps will sting and incapacitate insects and spiders to feed to their larvae.
Despite the hunting behaviors, adult wasps largely feed on pollen and nectar. Like bees, they are high energy organisms and require a lot of energy input (such as that found in flower nectar) to fuel that energy output. They don’t have the hairy bodies that bees do and therefore they don’t carry as much pollen from plant to plant as their more peaceful cousins but they are still capable of conducting a moderate amount of pollination.
Wasps will often be attracted to similar habitat as bees, so if you’re attracting bees, you will most likely get some wasps as well. If you’re in the vicinity of a wasp, the old adage ‘if you don’t bother it, it won’t bother you’ stands true so when near a wasp, it’s best to stand still until it moves away and then move away from whatever is attracting it.
8. Paper Wasps (Polistes fuscatus)
Paper wasps are one of the more social species of wasps, living in colonies in a nest that is a hanging globe like structure constructed out of what looks like papery material. The papery material is made of a mixture of wood and plant fibers mixed with the wasps’ saliva. Like bees, paper wasps have one queen per colony although the queen will have other females with her that assist her in caring for eggs and young. In the event that one of the other females lays eggs, the queen maintains her dominance in the colony by eating the eggs. Paper wasps are attracted to the nectar of plants such as milkweed. The pollen ‘packets’ of milkweed are quite sticky and will stick to the legs of an insect that walks across them. When the insect visits another plant, the pollen packets are deposited.
9. Yellow Jackets (Vescula spp.)
Although they pollinate in a similar fashion as the more docile paper wasps, few organisms smaller than 50 pounds instill the kind of fear in human beings the way that yellow jackets do. Named for the warning colors of yellow and black banding, their painful sting is not one that its victims soon forget. Females tend to be more aggressive, as they are the ones defending their young so it’s important to remember not to swing or flail when in the vicinity of one (as they may see that as aggression towards them) and to stay very clear of their nests. When the cold temps of the fall begin, the males will die off, leaving mated females to start a new generation the following spring.
10. Mosquitoes (Family Culicidae)
Yes! Those annoying, bloodsucking insects are also pollinators! The only mosquitoes that bite warm blooded organisms are the females and they do so in order to obtain protein to produce eggs. The primary food source for male and female mosquitoes both is plant nectar. As they move from plant to plant feeding themselves, they are also transferring pollen. Despite their preference for flower nectar, there are several plants that you can keep in your garden or on your porch that will effectively repel mosquitoes such as marigolds, lavender, lemon grass, garlic, and rosemary.
Bright, S. (2016, April 12). 21 Glorious Garden Plants that Attract Hummingbirds. Retrieved June 7, 2017, from Natural Living Ideas: http://www.naturallivingideas.com/21-garden-plants-that-attract-hummingbirds-2/
Helzer, C. (2013, August 20). The Softer Side of Wasps. Retrieved June 7, 2017, from The Prairie Ecologist: https://prairieecologist.com/2013/08/20/the-softer-side-of-wasps/
Miller, E. (n.d.). Mosquitoes are Useful to Pollinate Flowers. Retrieved June 7, 2017, from How to Get Rid of Mosquitoes: http://www.mosquitoreviews.com/mosquitoes-niche-pollinate.html
Ruby-Throated Hummingbird. (n.d.). Retrieved June 7, 2017, from Cornell Lab of Ornithology All About Birds: https://www.allaboutbirds.org/guide/Ruby-throated_Hummingbird/id
Sheila R. Colla, L. R. (2011, March). Bumble Bees of the Eastern United States. Retrieved June 7, 2017, from Xerces Society: http://www.xerces.org/wp-content/uploads/2008/09/Eastern_Bumble_Bee.pdf
Wasp Pollination. (n.d.). Retrieved June 7, 2017, from United States Department of Agriculture Forest Service: https://www.fs.fed.us/wildflowers/pollinators/animals/wasps.shtml
Writer, S. (2014, February 11). Yellow Jacket. Retrieved June 7, 2017, from Insect Identification for the Casual Observer: http://www.insectidentification.org/insect-description.asp?identification=Yellow-Jacket
Writer, S. (2016, January 5). Hummingbird Moth. Retrieved June 7, 2017, from Insect Identification for the Casual Observer: http://www.insectidentification.org/insect-description.asp?identification=Hummingbird-Moth
Writer, S. (2017, February 28). Eastern Tiger Swallowtail. Retrieved June 7, 2017, from Insect Identification for the Casual Observer: http://www.insectidentification.org/insect-description.asp?identification=Eastern-Tiger-Swallowtail