Spring is a busy time of year in the world of pest control.
With hundreds of insects coming out of hibernation to breed and feed, it can seem as if the whole world is being overrun. I’m a pest-guy by trade, and am accustomed to fielding questions from worried bystanders about how to ensure that this new flurry of activity doesn't become a problem for their home or business. Of all the insects indigenous to the Tidewater area, I am probably quizzed the most about the habits and biology of a group of pollinators known as ground bees.
The word "ground bee” has evolved over the years into a slang-word that is used to describe any stinging insect nesting in the ground.
Some species can be seen swarming in large numbers over ivy or thinning grass when the weather warms up in the early spring.
Others emerge from a single hole in the ground in late August or early September.
To the untrained eye, ground bees all look the same.
When it comes to ground nesters, though, there’s more than meets the untrained eye. In fact, it’s interesting to note that ground-nesters comprise two totally different species with dynamically different tendencies, behavior and nesting habits.
Let’s start with a little information about the bees that emerge mid-spring in the Tidewater area, as these are the true ground bees from a scientific perspective.
This early-emerging species of bee is classed in the family Andrenidae, and falls under the common name of solitary ground-nester. Though most of us think of oblong hives and social caste systems when it comes to bees, it turns out that the largest portion of the 20,000 species of bees in the world are members of this solitary nesting group.
“(They) are solitary bees which do not live in colonies. Andrenid bee burrows are made in the ground, usually consisting of a long vertical tunnel with lateral branches off of this tunnel to each cell. Sometimes large numbers of these bees will nest close together, particularly in bare-ground areas.” 1
In the Williamsburg area, solitary ground bees can be seen from late-March through mid-June. For whatever reason, they seem to have a particular affinity for nesting in English ivy. In this instance, the bees either make nests in the ground directly under the English ivy or set up camp in the dirt surrounding the outer edges of the leafy cluster, and then swarm in large numbers just over the top of the ivy during the day. Each nest has the surface appearance of an ant hill, with excavated dirt surrounding the entrance hole in the ground.
The bees’ habit of swarming over the ivy (or wherever else they may be nesting) is disturbing to some, who fear the swarm will become aggressive and attack if approached. Solitary nesting bees, however, are not aggressive in nature. The majority of the visible bees are males. Male bees do not have a stinger and are therefore harmless to people. Females are capable of inflicting a mild sting when handled roughly or caught inside of clothing, but do not have a disposition to attack people. During my inspections of areas reportedly infested with solitary nesting bees, I have, on more than one occasion, walked through swarms of several hundred of these bees without harm. For this reason, I rarely recommend chemical treatment as a means of coping with swarms. Though they seem to invade an area overnight, the bees typically depart as fast as they came, and their presence in any one area rarely lasts longer than a month. 2 Most professional pest management operators and entomologists agree that solitary ground bees pose no significant danger to the environment, and should be left alone if possible. In fact, since solitary ground bees are active pollinators, they are considered to be beneficial insects. If you are at home with some spare time and have a curious disposition, take this council from a clip off of http://www.pollinatorparadise.com/:
"My advice is to leave them alone; just don't walk barefoot around the nesting area while the bees are nesting. They are unlikely to sting your kids or pets, and you should be able to mow without disturbing them very much. If you mow early in the morning or in the evening there is less bee activity, and thus less opportunity to disturb them. In fact, I suggest that you spend some time with your kids sitting nearby and watching the bees come and go from their nests. Try to figure out how they dig their holes, what plants they are visiting for pollen and nectar (and pollinating in the process); observe how male and female behavior differs. Each hole is the entrance to the nest of a different female bee. How does each female know which hole belongs to her? How long does it take her to collect a load of pollen? This is a good opportunity for you to help your kids develop an appreciation for nature."3
Around the time that the docile solitary nesting ground bees retire for the season, another ground nesting insect emerges in the summer heat. These brightly colored “ground bees” are often seen boiling out of old rodent burrows, holes between tree roots, and even cavities in structural edifices. Truth be told, this species is actually not a bee at all. Instead, they are members of the wasp family; genus Vespula, and are commonly referred to as yellow jackets.
Yellow jackets, while similar in size to the solitary ground bee, are much different in behavior and nesting preferences than their peaceful counterparts. While the solitary ground bee nests alone in a freshly-dug burrow, yellow jackets are social insects that build intricate nests inside of preexisting cavities like rodent burrows. Instead of feeding on balls of pollen, yellow jackets prey on other insects and nectar. They are scavengers of human garbage, and prefer foods and liquids high in protein to feed their young. Yellow jackets are aggressive foragers, have the ability to sting repeatedly, and are easily provoked by the presence of humans, making them a threat to the safety of those in their immediate vicinity.
In the early spring, fertilized yellow jacket queens emerge from their winter hibernation to begin searching for a suitable place to build a nest. Once a location is secured, the queen uses a mixture of saliva and chewed-up wood pulp to build a waterproof multi-celled structure that will eventually be encapsulated and grow to the size of a soccer ball. She lays her eggs and feeds the larvae for a short time. Soon, these pupate into sterile female workers, who take over the duties of feeding the continuously expanding larval population.
Ironically, adult wasps are unable to digest the protein substances (chewed-up insects) they bring back from their hunting ventures. The larvae, however, can readily feed on this material. After feeding, the larvae secrete a sweet substance the adults are able to digest, creating an interdependent relationship called trophylaxis between the larvae/workers.
The nest continues to expand until the end of the warm-weather season.
At that time, the focus of the colony shifts from producing larvae to queen reproduction. As a result, the number of sterile workers begin to vastly outnumber the larvae. Since the workers cannot digest live prey and the larval secretion they depend on for sustenance is in short supply, the colony's food preference shifts from protein to sweets. This triggers an aggressive late-season sugar/carb binge in which hungry workers scour the area morning to dusk for food sources. From our perspective, swarms of ornery yellow jackets seem to take over outdoor activities during this time. Groups of anxious workers plague waste receptacles, soda stands, outdoor dining, picnics, and anywhere else there is a food source for the nest.
The aggressive behavior of yellow jackets coupled with their ability to mass- attack make them a formidable pest to deal with. Yellow jackets are able to release a pheromone that summons other nest-mates into the area for back-up protection. If they are swatted roughly , or, worse yet, smashed, they release this pheromone into the air, guaranteeing an escalation of the melee.
In almost all cases, it is best to call in a professional if a yellow jacket nest is located and needs to be destroyed. PCO’s are equipped with the correct tools and personal protective equipment to get the job done without endangering themselves, bystanders, or the environment. Under no circumstances should gasoline be used to destroy a yellow jacket nest, as this is dangerous to both the applicator and the environment.
In case you find yourself at an outdoor activity or other situation where there is heavy yellow jacket activity, follow these simple tips to minimize the risk of getting stung:
DO:
Keep drinks covered and look before you sip.
Remain calm when around yellow jackets. If foragers are harassing you, walk slowly away from the immediate vicinity or lightly brush the insect off.
Carry an insect sting kit if you are allergic to bee or yellow jacket stings. Kits are available with a doctor's prescription, and should contain a premeasured dose of epinephrine in an easy-to-use syringe. Familiarize yourself with application directions beforehand - it could save your life.
Don’t:
Swat or crush yellow jackets.
Wear bright colors or heavy perfume during yellow jacket season (dressing in white or khaki is best).
Panic when you see a nest – walk slowly away. If you accidentally disturb a nest (i.e. run over it with a lawn mower, etc.), get away from the area as quickly as possible, shielding your head with your arms. Refuge should be sought indoors or inside a vehicle. If these areas are unavailable, a thick cluster of bushes can provide a good respite. Jumping into a lake, pool or other body of water is inadvisable, as attacking yellow jackets will wait for you to resurface and resume their attack.
Though you may do all you can to avoid being stung, you still may find yourself nursing a wound or two by season’s end. If you do, ibuprofen or a comparable pain reliever will provide some relief, while meat tenderizer or a baking soda/water paste is said to work well as a local at the site of the sting.
If you have a history of allergic reactions to bee stings and you have not acquired a sting kit, get immediate medical attention if you are stung - even if symptoms are not yet evident. Massive swelling at the site of the sting, shortness of breath, dizziness, and hives are all symptoms that indicate a need for prompt action. There are an estimated 50 deaths per year as a result of yellow jacket stings - don’t be one of them.
As we prepare to enter yet another stinging insect season, I wish you luck in keeping yourself out of trouble. Hopefully, you will be a little less alarmed when you see those docile, early-emerging bees in April and a little more cautious when you encounter the audacious late-August yellow jackets.
