Tuleyome's Science Corner - Paper Wasps and Yellowjackets

Kristie Ehrhardt • September 21, 2023

Paper Wasp and Nest

The Sacramento region is home to at two very common types of social wasps (wasps that live together in a community); paper wasps and yellowjackets. Both yellowjackets and paper wasps belong to the family Vespidae which contains about 1,100 species. Yellowjackets belong to the subfamily Vespinae which contains two genuses (Vespula and Dolichovespala). Paper wasps belong to the subfamily Polistinae which contains approximately 300 species worldwide, 22 of which are in California and belong to the genus Polistes.


Yellowjackets and paper wasps are commonly confused and misidentified because they look quite similar, however there are some notable differences if you don’t mind getting pretty close to them. Yellow jackets are typically black with yellow markings, are slightly less than an inch long and appear chunkier lacking the very tapered “wasp waist” that paper wasps display. Paper wasps are slightly bigger than yellowjackets, dark brown with yellow markings and have orange-tipped antennae and long rear legs that dangle behind them in flight. Both yellowjackets and paper wasps build nests out of paper which consists of chewed plant material, wood and saliva. Both begin nest construction which is made of rows of individual hexagonal cells in the early spring as the weather warms and the queen has emerged from hibernation. Depending on the species, yellowjacket nests can be underground often in abandoned rodent burrows (sometimes this species is called “meat bees”) while other species build a suspended nest from a structure or inside the walls of a building. Generally, yellowjacket nests they are much larger than paper wasp nests as the colonies can host many thousands of individuals and ends of the cells are sealed with a paper envelope so the embryo is not visible. Paper wasp nests are smaller with open hexagonal cells and they are always attached to a structure by a small stalk or pedicel and look like a tiny, hanging umbrella. Some species of paper wasps manufacture a chemical that keeps ants from crossing the pedicel and accessing their larvae. Colonies of paper wasps are much smaller and may only support 100 to 200 individuals. Rather than build a single large nest, paper wasps use several nest sites which may include the eaves of a house or shed, outdoor birdhouses, benches, grills and other outdoor structures and shrubbery.


I recently learned most wasp species, yellowjackets and paper wasps included, play an important role in biological pest control. In the early spring as wasp colonies are growing, they prey on species that impact crops such as caterpillars, aphids, beetle larvae and flies. In late summer and early fall the colonies forage on nectar to feed the queen and workers. As a result, they are also important pollinators. It is also this time when yellowjackets and wasps may come into more frequent contact with humans by swarming around trash cans, barbecues and even open soda cans looking for sweet things.


Generally speaking, paper wasps are shy of humans, far less defensive and much less prone to sting unless their nests are disturbed. Yellowjackets are more irritable and aggressive and seem to almost want to pick fights with humans. Like all wasps, both species can sting multiple times and although not common, anaphylactic reactions can occur. Studies have shown that some species that display brighter colors have larger venom glands and as a result are more venomous. It’s thought that the brighter color is a warning to keep predators away from the nest.


The Sacramento-Yolo Mosquito and Vector Control District website states that it is dangerous to confront a yellowjacket nest and they offer free help with nest removal. They can be contacted here for more information.


-Kristie Ehrhardt (kehrhardt@tuleyome.org)

Tuleyome Land Conservation Program Manager


RECENT ARTICLES

By Bryan Pride February 6, 2025
With a new Administration keen on identifying untapped sources for energy and natural resources, discussions on “rolling back” the Antiquities Act of 1906 are rising within Congress and the Administration. The Antiquities Act is one of the most important tools available for the preservation of public lands, water, and historic sites. Passed by a Republican-led Congress and signed into law by President Theodore Roosevelt, the Act has been utilized by eighteen U.S. Presidents— nine Democrats and nine Republicans—who have collectively declared 145 national monuments . This bipartisan legislation remains essential for maintaining the integrity of natural and cultural resources. Under The Antiquities Act, the President has the authority to reserve or withdraw federal lands or waters containing objects of historic, scenic, scientific and cultural significance. This protection prevents potential harm from commercial development, looting, and habitat destruction. Key provisions of the Antiquities Act established several crucial tools for managing resources on public lands. These tools include: Presidential authority to establish national monuments from existing federal lands Requirements to secure permission from federal land managers before conducting archaeological investigations or removing objects Authority for the Secretaries of Agriculture, Interior, and War to review and grant permits to qualified institutions Requirements that materials, if excavated, be permanently preserved in public museums Authority to develop uniform rules and regulations for implementing the Act The legislation placed the preservation of public lands, water, scientific and scenic sites firmly within the federal government's responsibility and the public's interest. Federal land-management agencies must protect these sites because of their contributions to advancing scientific knowledge and overall public benefit. Since 1906, presidents have exercised their authority under the Antiquities Act nearly 300 times. Including many iconic National Park locations such as the Grand Canyon (1908) to the more recent National Monuments including Berryessa Snow Mountain (2015) and Chuckwalla and Sáttítla (2025) . The Antiquities Act's preservation mandates have generated substantial economic benefits. National monuments create jobs, enhance communities, and strengthen local outdoor recreation economies, which contributed $639.5 billion to national GDP in 2023 . According to the National Park Conservation Association, regions surrounding national monuments also experience growth in employment and increased per capita income following monument designation, demonstrating their positive impact on communities. The national park system attracts nearly 300 million visits to National Monuments and Parks each year, contributing to approximately $30 billion in economic activity. Each dollar invested in park operations yields $10 for local communities. Across party lines, public opinion strongly supports National Parks and Monuments based specifically on their economic impact, with 75% of voters believing public lands attract high-quality employers and jobs to their states, and 80% agreeing these lands support their economy and quality of life. This economic-focused support is distinct from the even broader 95% voter approval for federal management of public lands , which considers additional scientific and recreational benefits beyond economic factors. Efforts to undermine The Antiquities Act contradict public opinion and would compromise its fundamental purpose—enabling presidents to act swiftly in protecting sensitive federal lands. Anti-Antiquities Act activities could expose unique federal lands to development and mining claims, degrading resources and redirecting economic benefits from public to private entities. While The Act provides designation authority, it does not automatically establish management plans, programs, or funding for designated monuments. This is why Tuleyome’s ongoing work with local communities is crucial. Tuleyome collaborates with the public and communities connected to Berryessa Snow Mountain National Monument to develop co-management plans that protect these special places while considering both land preservation and public interests. If you're interested in learning more about how to be involved in helping protect and steward Berryessa Snow Mountain National Monument, reach out to Bryan Pride. -Bryan Pride ( bpride@tuleyome.org ) Policy Director
By Nate Lillge February 6, 2025
I learned about Tuleyome in 2006 when I met staff and the Board at a workshop. Their passionate volunteers were sharing information about their work throughout the Northern Inner Coast Range. I'm thankful for groups like Tuleyome who advocate for our public lands and all user groups. As an avid hiker, I appreciate their commitment to trail building and maintenance as well as the Boot Bank. My first donation to Tuleyome was motivated by their work to protect the Berryessa Snow Mountain region as a National Monument. I was impressed by their innovative approach to addressing environmental issues while engaging diverse stakeholders. I know how important it is for organizations like Tuleyome to receive unrestricted support. The advocacy isn't as effective if the staff don't have the resources to do their vital work. I'm happy to donate so Tuleyome can use the funds where they are needed most, enabling them to respond quickly to changing circumstances and emerging needs. Tuleyome's efforts have significantly enhanced the protection and accessibility of the northern Inner Coast Range mountains. This is key to ensuring the preservation of its unique ecological, recreational, and cultural values for current and future generations. Thank you Tuleyome for all you do!
By Kristie Ehrhardt February 6, 2025
 YES! Leaves of three - let them be. Right but it’s winter and what if there are no leaves? Poison Oak ( Toxicodendron diversilobum ), Pacific Poison Oak or Western Poison Oak is a widely distributed woody shrub or vine that belongs to the Sumac (Anacardiaceae) family. The Sumac family is also known as the Cashew family which contains the tree that gives us that delightful buttery nut (it’s actually a seed) as well as the tree that provides mouthwatering mangos and the tree that produces savory pink peppercorns. How can such a delectable family also give us such an annoying plant? Poison oak (PO) is not even remotely related to oaks but the leaves sort of resemble oak leaves. They are divided into three leaflets that are about one and a half to four inches long. The species name, diversilobum, refers to the diversity of leaf size and shape; the edges can be toothed, scalloped or lobed and vary greatly. PO is deciduous and the new leaves are usually dark golden or bronze when they are just beginning to unfold in early to mid-spring. They turn a bright then darker glossy green and ultimately transitioning a stunning scarlet red then fading to pink in late summer and fall. The small flowers are greenish-white and appear in late spring to mid-summer and if they are fertilized they become small creamy white berries. Growth forms vary depending on where it is occurring, but it thrives in full sun as well as shady environments. In open sunlight it can grow as a tall, dense shrub or tree with a thick trunk, or a woody vine winding around and up into the canopy of tall trees, fences and other vegetation. In shady areas it can occur as a dense thicket, vine or anything in between. It is prolific and spreads by seed dispersal and through underground rhizomes. It is widely distributed in Western North America from British Columbia, Washington, Oregon, California, Nevada and Baja Mexico and occurs extensively throughout the Berryessa Snow Mountain National Monument. It occurs in chaparral and woodland habitats as well as coastal sage scrub, grasslands, oak woodlands and mixed evergreen forests below 5,000 feet. It’s a common understory plant in riparian corridors and grows alongside Giant and Coastal Redwoods. PO is even a constant quagmire in dry-farmed mountain orchards, urban parks and recreation areas. In fact, it’s kind of hard to find a biome in the Central Valley of California that doesn’t support Poison Oak unless you go into the Great Basin or the southwestern edge of the Mojave desert. The genus Toxicodendron contains many plants that cause allergic reactions. The oil of the plants contains a compound called Urushiol that causes the reaction and it is found in all parts of the plant except the pollen (ironic!). Direct contact with the plant or anything that has touched the plant such as clothing, pets, tools or vehicles can result in painful, itchy blisters. Not everyone is allergic to it, however, repeated exposure can lead to heightened sensitivity. If an area dense with PO is burning, inhaling the smoke can cause a severe internal reaction. Which leads me to why you can still have a reaction to PO in the winter after all the leaves have fallen. It’s a lot harder to spot when it’s just a twig, branch or bare vine along the edge of the trail. Twigs and stems still contain the oil that produces reactions and you may not even realize that you’ve brushed up against it until it’s too late. Keep an eye out for exposed, reddish-brown whip-like sticks coming out of the ground, especially if you know you’re in an area where PO is present. Sometimes the berries remain on the plant even though the leaves have fallen off and occasionally the stems show black marks where the sap may have oozed out and dried. If you know you’ve been in contact with PO, washing your exposed skin with dish soap is a great way to remove the oil from your skin and washing your clothes as soon as you can so you don’t transfer the oil to yourself, others or additional laundry is also a good idea. If your pets have been scampering about where PO could be present, give them a good bath before you snuggle up with them and consider wearing long rubber gloves like those made for doing dishes to avoid the oils transferring to you. PO isn’t all bad; Black-tailed Deer, California Ground Squirrels and Western Gray Squirrels among other species consume the leaves of the plant which is rich in phosphorus, calcium and sulfur. Many birds eat the berries and utilize the plant for shelter. Research has shown that livestock, domestic dogs and other native wildlife species do not have adverse reactions to Urushiol. Native Americans cooked with it, used the stems to make baskets and used the juice from the fruit to dye materials black. Don’t stay off the trail, just take precautions and enjoy winter hiking in your favorite monument! -Kristie Ehrhardt ( kehrhardt@tuleyome.org ) Tuleyome Land Conservation Program Manager
Share by: