North American yellow jackets are predatory wasps, ubiquitous-social hunters, and are a common sight in the continent during the spring and summer months. These are colonial creatures that have a distinct class system comprising of the fertile queen, infertile workers, drones and new queens. Yellow jackets form some of the most prominent pests in the western part of the North American continent along with the paper wasps. These wasps are predominantly called as yellow jackets in North America while they are referred to as wasps in Australia and the United Kingdom. Yellow jackets have a striking resemblance to bees and often are misunderstood for them. They do have stingers just like the bees only that it is not barbed and hence they are capable of stinging a victim multiple times unlike the bees.
Yellow Jackets Behavior, Diet and Habits
Yellow jacket workers forage for food within 1,000 feet of their nest, approximating to the size of three football fields. They feed on flies, grubs, beetles, caterpillars and other harmful garden pests thereby in a way protecting the garden from these pests during the summer months. During the early fall period, when there is food scarcity, yellow jackets are drawn to protein sources, and scavenge for fish, meat and sugary substances like hamburgers on the barbecue grill, sodas, sugary juices, fruit drinks, sweets, etc. This behavior of these insects at this time gets them into human conflict, making them a potential hazard at picnic spots, near trash cans, etc.
How Can Yellow Jackets Be Identified
Identification at first sight
Yellow jackets as the name implies have a distinct yellow coloring on their bodies. They have thin waists and have two long antennas which set them apart from the bees that have a stout body. The yellow jackets can be found commonly on the ground as they build their nests underground or inside tree hollows. Yellow jackets have a rapid side to side movement pattern while landing which distinguishes them from the bees.
The wings are usually a translucent golden-tan. Yellow jackets fold their wings to their length while resting which is one of the most distinguishing features among wasps. Most yellow jacket species are black and yellow in color barring the white and black colored Bald Faced Hornet (which is a type of yellow jacket even though the name suggests it as different). Some yellow jackets have red colored abdomen unlike the common black coloring. A yellow jacket worker can be about 12 mm/0.5in in length. The queen is larger than the worker and hence she is about 19 mm/0.75in in length.
Yellow jackets have well defined mouth parts with strong mandibles that help in capturing and chewing insects, with special probosces for sucking nectar, fruit, and other juices. These wasps have Lance-like stingers that have very minute barbs that enable it to sting multiple number of times.
Yellow Jackets and Honey Bees
Yellow jackets are more often confused with honey bees due to the similar coloring of the two. Yellow jackets are wasps and have the characteristics of the same unlike the bees. Yellow jackets are slightly bigger in size when compared to bees and have a smaller waist than the latter. In contrast to honey bees, yellow jackets are not covered with tan-brown dense hair on their bodies. Yellow jackets have a side to side flight pattern which they exhibit just before they land which separates them from the bees which land directly.
Yellow jackets though help are not very efficient pollinators as the bees. They do not have flattened and hairy hind legs like the bees that help to carry and transport pollen. Yellow jackets do not have a barbed stinger thereby making it capable of stinging multiple times unlike the bees. Occasionally though, the stinger gets attached to the victims and gets pulled out of the wasp’s body. Bees on the other hand have a barbed stinger that attaches itself to the victim and more often than not pulls out the abdomen in the process thereby killing the bee.
Death of the Colony and Beginning of a New Cycle
The parent colony workers dwindle at the end of the autumn season and usually leave the nest and die once the young queens and drones leave the colony. The founding queen of the colony too dies in similar fashion and at times remains in the nest till her death. Abandoned nests quickly decompose and disintegrate during the winter months. The structures of the nest remain, as long as the nest is kept dry. Yellow jackets do not use a nest once it has lived the season. During the spring the cycle starts once again as the new queens begin to build independent colonies of their own.
When the nest is at its peak size, reproductive cells are built and new male drones and fertilized young queens are produced. About hundreds of these adult reproductive insects remain in the nest nurtured by the workers. New queens build up fat reserves that help them to wait out the winter. The new queens and the male drones leave the parent colony to mate. After mating, the drones breathe their last the fertilized new queens search for a new hiding place to wait out the winter to start independent colonies of their own.
Building the Nest
The inseminated queens emerge out on the onset of spring's warmer temperatures once it is warm enough for them, either late spring or early summer either late April or early May when the daytime temperatures consistently reach the upper 60s to low 70s Fahrenheit. They choose a nesting site that is away from human intervention usually a soil cavity such as an abandoned mouse nest or the hollow of a tree and builds a single comb that comprises of several cells. The nest is constructed from wood pulp, chewed up plant fibers and hence appears to be papery. The small paper nest comprises of 30 to 50 brood cells in which the queen lays her a single egg in each of these cells.
The Class System
Yellow jackets are predatory insects that live in colonies with a distinct class system. They have four classes – the Queen who is the supremo, the female workers, the male drones and the inseminated young queens that overwinter and eventually build their own colonies in spring. The inseminated queens hide themselves in protective places during the winter time – man made hollows, tree hollows, soil cavities, leaf litter, under barks of trees, inside tree stumps, hollow logs, etc. are some of the popular spots where they can be spotted.
The first emerging yellow jackets are the first set of workers in the nest. They assume the responsibilities of building the nest further, feeding the next sets of larvae and defending the colony. The queen is the only reproducing member in the colony and hence she is integral to the colony’s survival. The workers get particularly aggravated if they know that the queen and the larvae are in danger and defend them vigorously as a result. From now on the queen focuses only on laying more eggs and the larvae are cared and protected by the workers. Over the summer months the nest is enlarged as more workers emerge and additional layers of comb are enclosed in the paper envelope housing anywhere between 10,000 to 15,000 cells and 4,000 to 5,000 workers.
Eggs and Larvae
The eggs are milky white and typically "sausage-shaped." They are about 1 to 2 mm in length. The eggs hatch into larvae and about for the next 18 or 20 days the queen forages for food and feeds these first larvae with fish, meat, small insects, etc. whichever the queen can find. The queen also enlarges the comb with additional wood pulp during this time. The legless grub like larvae are creamy white in color, it is sized just larger than an egg at the early stages after hatching and grows up to near adult size at maturity.
The first three instars of the larvae are attached to the cell wall while the last two move about within the cell. At the maturity stage, the larvae pupate and resemble a mummified adult. The pupae develop adult coloring just before they emerge as adult wasps. Immature yellow jackets cannot be seen unless the nest is torn open or there is a sudden loss of adult workers that to an exodus of starving larvae. The size of the pupa at this stage is the same as that of the adult. The larvae after this stage emerge as infertile females called workers.
Notable Species of Yellow Jackets
Ariel Yellow Jacket
The Dolichovespula Arenaria can be easily identified by its nest which it builds above the ground allowing it to grow to impressive sizes. It is capable of building underground nests as well and can be popularly found on roof overhangs and protected building surfaces. This is not a picnic pest like the other yellow jackets.
German Yellow Jacket:
The Vespula Germanica is a very aggressive scavenger of sweet drinks and meats and hence poses a very grave sting hazard during the summer months. It is also capable of surviving winters and builds nests surrounding homes that make it easy for scavenging activities. It can be popularly found in attics and wall voids of a house. It is abundantly found across the northeastern and mid-western regions of the USA and also in the western regions of Washington, Idaho, and California.
Bald Faced Hornets:
Though the name suggests differently this is the Dolichovespula Maculata species of yellow jackets. These insects are black and white colored heavy bodied wasps, with ivory colored marks on their head and at the end of the abdomen. They build soccer ball sized papery nests high on trees and roof peaks. They are not as aggressive as the other species of yellow jackets.
Among the species of the yellow jackets, the Dolichovespula species that consists of the aerial yellow jackets and the bald faced hornets build visibly exposed nests on high structures such as trees, manmade structures, roofs, etc. This is one of the characteristics that these two species share with the hornets and hence are often mistaken for them. The Vespula type of yellow jackets build concealed nests in the underground. All yellow jackets barring very rare exceptions last for only one season.
The nest is created by the founding queen, and developed by the workers. At the end of the season, the nest reaches the size of a basketball. In some parts of United States, the Pacific Islands, New Zealand and Australia, where the winters are mild, the nests overwinter. Nests that survive several seasons can become very massive and is also capable of producing and housing multiple egg laying queens.
Yellow jackets build their concealed nests in between wall structures, wall voids, crawl spaces, soil cavities, crevices, cracks, attics, barns, hollow stumps, abandoned animal burrows, under eaves of houses, etc. The Western yellow jackets commonly referred to as the ‘meat bees’ prefer the subterranean locations, and create their nests in the ground. The entrance to the underground nest is in the size of a nickel and hence can be very difficult to locate.
The nests are made from plant fibers gathered from weathered or decayed wood or even from living plants. The wood and plant fibers are then chewed to become a papery like pulp substance which is used to build the nests. The nest is structured with number of rounded combs that are attached one below the other. A layered envelope covers these combs allowing only one opening for the insects to enter and exit.
A yellow jacket’s nest can contain anywhere between 300 to 120,000 cells, though a majority of these nests average around average 2000 to 6000 cells and measure 3 – 6 inches in diameter. Each nest is capable of housing several thousands of yellow jackets at a time. Some of the larger nests are formed as a result of some perennial colonies that do not die during the winter months and hosts several queens at the same time. In places where mild winters are followed by early spring, there can be unchecked growth of the colonies that do not die during the winter and instead keeps growing to a staggering size with about a million cells and over 100,000 workers.
Large Nest Discoveries
In some extreme cases, there have been instances of yellow jackets nests expanding to fill into much larger spaces like the insides of abandoned vehicles, unoccupied barns, deserted houses, etc. There is documented evidence of extremely large yellow jacket nests in the southern parts of the United States such as Georgia, Florida and Alabama. A perennial yellow jacket nest that was found in California was nearly four feet long, one in Florida was 9 feet long and a huge nest in Clermont, Florida measured about 6 feet in height and 8 feet across and weighed 200 pounds. A pest control expert had estimated that this nest hosted about 25,000 yellow jackets.
The best record yet for the largest yellow jacket nest was the one found in New Zealand in 1960. This nest was almost 15 feet tall, with an estimated weight of 1,000 pounds, had 1890 combs, and contained several million cells! In August 1991, a yellow jacket nest discovered in Charleston County contained an estimated 250,000 workers. The nest was estimated to have been in existence for about over a year.
Yellow Jackets Don’t Recycle
The concept of recycling doesn’t work well with the yellow jackets as they do not re-use the same nest to build a new colony. The end of warm weather and the beginning of cold weather sees the insects abandoning the nest one after the other, leaving it to wither and die in the cold months.
How to Get Rid of Yellow Jackets
The best time to get rid of a yellow jackets nest is during the inactive period during winter. Though it may not be easy to spot a hiding queen, unearthing burrows, cleaning holes in walls, the attic, crevices, unearthing soil cavities, etc., can help in killing the lone queen. There is also a possibility to kill the nest by killing the queen when she is foraging for food and trying to build the nest. If a single yellow jacket is found to be moving around the house or in the garden – a close watch will reveal its entry point to the nest. Trapping it at this time will be ideal as a little later will see workers emerging, growing in numbers, gaining strength and posing serious sting hazards especially during the fall when there is scarcity for food.
Identifying The Yellow Jackets Nest
The first and foremost thing to do is to identify the nest in the ground. Aerial nests are easy to find but locating an underground nest can be tough. There is a simple way to do so. Observing workers when they return after foraging for food is the ideal way to identify a nest. A freshly caught small fish can be diced in the middle and hung from a string at about 6 ft off the ground. Foraging yellow jacket workers will be attracted to the raw fish, will chew off a tiny bit of the flesh and take it back to the colony. Very soon there will be a bee-line of yellow jackets that fly from the nest and to it. Yellow jackets once they find food take it straight back to the nest. If one follows this bee-line the entrance of the nest can be easily identified.
Lure traps are available across retail stores that sell pest control supplies. Lure traps can help in reducing the number of localized worker yellow jackets that forage for food but they are not effective in eliminating large numbers. A chemical or any lure such as meat, sweets, etc. can be kept inside the traps. The yellow jackets are attracted towards it. The trapped yellow jackets eventually struggle and die in the process.
Lures need to be replaced periodically as spoilt food does not attract these insects. The trap can be removed only after ensuring that all the trapped insects are trapped and are not flying free inside it. The traps need to be placed between the landscape that serves the nesting site and the area that needs to be protected. Lure traps work best as queen traps during the early spring days when the queen is looking for food to feed the first batch of larvae in the nest.
Homemade water traps can be used to lure the insects. All that is needed is a string, a protein for bait (liver, fish or ham) and a five gallon bucket of water. The bucket needs to be filled in with soapy water and the bait must be tied suspended an inch or two above the water. A wide holed mesh screen needs to be placed around this water trap to ensure that other animals do not reach or consume the bait. The yellow jacket after removing the bait flies down and gets trapped in the soapy water eventually drowning in the end. Similar to the lure traps, the water traps too are best when used as queen traps during the early days of spring. In the later months, when there is a heavy population of yellow jackets, these traps may not prove handy.
An ideal way to kill a nest is to smother them. Fill a wheelbarrow with ice and quickly in one sudden motion dump it over the exit and entrance hole in the nest. Quickly cover the entire area with a heavy tarp that is weighed down by bricks, a big wooden board, a large piece of sheet metal, or any other heavy object. Once done, cover this entire tarp with wood chips or soil. Another method is to cover the hole with a thick piece of clear plastic sealing the edges tightly to the ground. When the sun is out, the ice inside starts melting and the insects along with the nest eventually die. Important though, not to open the sealed nest for about three or four days to be sure that the entire colony is wiped out.
Wasp Control Sprays
It is essential to use yellow jacket control sprays during the night as all the workers are back home after a day’s foraging work. The nest entrance can be identified and marked during the day time for easy identification in the dark. There are numerous wasp control sprays that are available in the present day that can be used to get rid of the yellow jackets nest. Aerosol formulations of insecticides labeled for use for wasps and yellow jackets can be used to get rid of these insects.
There are some organic choices as well with mint oil as the active ingredient that does not harm the soil. There are also some special sprays that freeze on contact with the insect. Pesticide dusts are also as effective and are recommended more than the sprays. It is important though to follow the exact directions and take all the precautions that are mentioned on the label of the pesticides. It is prudent to wear protective clothing and eyewear before indulging in this kind of control measure. It is best recommended to hire a pest control professional to avoid sting attacks.
Eliminating and Discouraging Nests
Knocking down a newly created yellow jacket nests can be the best way to ensure that there will not be any hazard to people. This will cause the queen to find a new site and hence will move away from the place. But this may be difficult as yellow jackets are usually spotted after the nests and population grow substantially and hence knocking down nests without knowing the number of active workers inside, may pose sting hazards.
Boiling and Drowning
Some pest control experts recommend pouring down 10 plus gallons of hot boiled water into the nest. Soapy water also does the same trick. This does not harm the soil and hence is one of the most recommended control methods. It is pertinent to remember that the insects that do not get killed by this impact can come back very aggressively posing repeated stinging hazards.
Control Measures On A Cool Evening
Control measures can be effectively used on a cool evening when the workers are back from foraging for food during the day. The insects are very sluggish in cool temperatures which can help in getting rid of them when they are not very aggressive. It is recommended not to hold a flash light on the nest as yellow jackets are attracted to the light and even though they are a little sluggish can start attacking if they feel threatened.
There are some animals and birds that prey on social wasps like praying mantis, bears, raccoons, skunks, spiders, birds, reptiles and amphibians who can be allowed in the garden to keep yellow jackets at bay. But this has not yielded satisfactory results but can be effective in the long run.
What You Must Not Do
Some people come up with innovative ways to kill a yellow jacket nest and end up ruining the soil, polluting the ground water and introducing harmful pollutants into the environment. Hence, as much as it is important to know what can one do, it is equally important to know what one must not.
Never Pour Gasoline
Gasoline, kerosene or any other toxic liquids or inflammable products are a no go here. If these do not kill the insects on contact, it can end up infuriating them furthermore. Also, these are soil pollutants that will ruin the purity of the ground water. If the EPA detects it, it is possible to end up paying for a very expensive clean-up operation in the neighborhood.
Do Not Burn It
Never try to burn down a yellow jacket’s nest, it will only end up in infuriating the insects that will come after the person creating extreme sting hazards as the insects come after the person responsible for it. Burning can also create smoke and invariably can set dry grass on fire posing serious hazards.
Are Yellow Jackets Dangerous?
The answer is yes and no. Yellow jackets are dangerous to humans who are allergic to their sting or for people who are stung way too many times by many numbers of yellow jackets. These wasps are responsible for about three deaths in the United States as a result of their harmful stinging. Yellow jackets are very unpredictable and extremely aggressive by nature. They don’t lose their stinger like the bees which increases the possibilities of multiple stings if the insect is disturbed or feels threatened. At times yellow jackets are also known to attack even if they are unprovoked.
Yellow Jacket Sting – The Danger
A yellow jacket sting can be painful and can cause some serious health hazards in some individuals. The stinger is used to inject the venom inside the victim and the destructive enzymes in the venom have the ability to cause tissue damage. It depends on the quantity of the venom that is thus injected. A swarm attack can lead to more wasp venom in the body of the victim that has the potential to damage red blood cells and other important organ tissues.
The broken down tissue debris is carried to the kidneys of the victim that is usually excreted as a process. In the case of a swarm attack, there is too much of debris and waste products that can lead to blockages in the kidney which result in renal insufficiency or renal failure. Victims who are in this condition may need immediate medical attention and can be recommended dialysis to cleanse the kidney off the blockages.
Threat to Nest and Queen
Yellow jackets defend their queen and nest aggressively and at even a slight threat, can come out in numbers and attack. Hence, it becomes important to ensure that a yellow jacket nest is removed if it is present anywhere near homes or places where there is more human traffic.
What To Do If Stung By A Yellow Jacket?
Reactions to yellow jacket stings largely depend on the individuals and their allergic reactions to the sting. Reactions to stings can result in substantial swelling or intense sensations, tenderness, itching and allergic responses that can also be life threatening at times. Hence, it is best to know what to do when stung by a yellow jacket;
Step 1: Run
Run, as fast as you can to a protective area where they cannot enter! This is because, yellow jackets once they sting a victim, they mark the enemy through a chemical that is comes with the venom. Other yellow jackets in the area, recognize the threat and eventually swarm after the victim. Running away will ensure that there are no more sting threats.
Step 2: First Aid
Wash the sting site with soap and water as it helps to remove the venom to a certain extent. To reduce the pain and remove the venom the following first aid applications can be given to the victim:Fermentation of cold water or ice with a wet cloth, A paste of meat tenderizer containing papain with water, A paste of baking soda and water, A poultice made by chewing a piece of plantain, Rubbing the cut side of an onion , Toothpaste, Preparation H & A damp tea bag.
What Not To Do For Yellow Jacket Stings
Never take any kind of sedatives without the consultation of a medic. It is also not good to consume alcohol after a yellow jacket sting.
Signs of Yellow Jacket Sting Allergies
Anyone can develop an allergy for yellow jacket stings and here are some signs that will help to identify it;
- Dizziness or fainting
- Difficulties in breathing
- Constrictions in the chest and throat area
- Widespread irritation
- Swellings in non sting sites and other parts of the body
Benefits of Having Yellow Jackets Around
It can be advantageous having yellow jackets around too! These insects are a great balance to nature and hence it is necessary that they must be left alone if they are found to be away from human traffic. Here is a list of reasons why they are beneficial to us:
- They help in eliminating garden pests as they feed on them and feed them to their growing larvae
- Yellow jackets also act as pollinators even though they do not do it as a full time job like the bees
- They feed on leftover foods of humans who picnic and pollute forest areas. This ensures that the balance of nature is restored fast and easy.
- Abandoned yellow jacket nests become homes for small animals and insects during the winter months. Some protected aerial nests also serve as a nest for small birds during the cold days.