BEES AND WASPS

INTRODUCTION

The insects most beneficial to humans are found in the large insect order Hymenoptera. Not only are the bees and many of their relatives pollinators of flowering plants, including fruits and vegetables, but thousands of species of small wasps are parasites of other arthropods including pest insects. Without these parasites that limit the growth of insect populations, pests would overtake most crops.

The urban pests of the order Hymenoptera are the stinging insects. Although the first image to come to mind implies danger to humans, these yellow jackets, hornets, and wasps sometimes serve our interest: They feed their young largely on flies and caterpillars.

Many of these stinging insects are social. They live in colonies with a caste system or a division of labor and overlapping generations -- all offspring of one individual reproductive. Some of these colonies persist for many years (ants, honey bees) and others, like stinging wasps, start anew each year.

THE AFRICANIZED BEE

The Africanized bee is the same species as the European honey bee kept by beekeepers all over the United States. Introduced into Brazil from southern Africa, it is adapted to longer warm seasons than are northern honey bees.It is thought that this bee will advance as far into the northern temperate region as it has into the southern temperate region. If this is true, Africanized bees will be distributed north in a line that will reach from southern Pennsylvania, west to Seattle, Washington.
Africanized bees do not store as much honey to take them through the winter as honey bees do. They have smaller colonies and tend to swarm more often. Smaller swarms allow colony development in smaller cavities. In South and Central America, Africanized swarms settle in hollow trees like northern honey bees; they also colonize in rubber tires, crates and boxes, wall voids, abandoned vehicles and other protected places that abound in urban areas. Worker bees tend to mob intruders. The urbanized Africanized honey bee presents a new management challenge not only to beekeepers but to urban pest management technicians.

CARPENTER BEES (Xylocopa)

Carpenter Bees are not social insects; they live only one year. The most common Carpenter Bee, Xylocopa virginica, is distributed throughout the eastern half of North America. This bee is a large insect with a hairy yellow thorax and a shiny black abdomen. Superficially, it resembles yellow and black female bumble bees, which are social and more closely related to honey bees. Western Carpenter bees are also large, shiny, sometimes metallic, and are shaped like bumble bees.
Carpenter bees bore in wood and make a long tunnel provisioned with pollen and eggs. They prefer to enter unpainted wood and commonly tunnel in redwood and unpainted deck timber. They will also go into painted wood especially if any type of start hole is present. New females reuse old tunnels year after year; they are also attracted to areas where other females are tunneling. Egg laying and tunnel provisioning occurs in the spring. Males hover around the tunnel entrance while the female provisions the nest and lays eggs. Males dart at intruders belligerently but they can do no harm; they have no stingers. Since these bees are not social, there is no worker caste to protect the nest. Stings of females are rare. New adults emerge after the middle of summer and can be seen feeding at flowers until they seek overwintering sites, sometimes in the tunnels.

 HONEY BEES (Apis mellifera)

The honey bee was introduced into the United States in Colonial America. Honey bees are highly social insects and communicate with each other, relaying direction and distance of nectar and pollen sources. Bees make combs of waxen cells placed side by side that provide spaces to rear young and to store honey. The bee colony lives on the stored honey throughout winters, and therefore, can persist for years.

When colony populations are high, the queen may move part of the colony to new harborage. Bees swarm at this time, usually finding hollow trees to begin their new colony, but they occasionally work their way into building wall voids.

A honey bee colony in a house wall can cause major problems. The bees can chew through the wall and fly inside. Their storage of large amounts of honey invites other bees and wasps. Their detritus (e.g., dead bees, shedded larval skins, wax caps from combs and other material) attracts beetles and moths.

When a bee colony is found in a building wall, it must be killed. Killing can be accomplished in the same way as killing yellowjackets in wall voids is done. Listen to the bee noise from inside rooms to locate the exact position of the nest in the wall to assure that the whole colony is treated.

After the colony is dead, remove the nest. If the nest is not removed, the wax combs -- normally cooled by the bees -- will melt and allow honey to flow down through the walls. Honey stain can never be removed; the walls will have to be replaced. As well, the freed honey attracts robber bees and wasps. The comb wax will attract wax moths that may persist for several years. The dead bees attract carpet beetles.

Close up of honey bee head.

After the colony is killed the entrance hole should be caulked or repaired to prevent further bee infestation.

Bee Stings vs. Wasp Stings

Honey bee venom contains almost 20 active substances.  Melittin, the most prevalent substance, is one of the most potent anti-inflammatory agents known.  It is 100 times more potent than hydrocortisol.  Adolapin is another strong anti-inflammatory substance, and inhibits cyclooxygenase, also creating analgesic activity as well.  Apamin inhibits complement C3 activity, and blocks calcium-dependent potassium channels, thus enhancing nerve transmission.  Other substances, such as Compound X, Hyaluronidase, Phospholipase A2, Histamine, and Mast Cell Degranulating Protein (MSDP), are involved in the inflammatory response of venom, with the softening of tissue and the facilitation of flow of the other substances.  There are also measurable amounts of the neurotransmitters Dopamine, Norepinephrine and Seratonin.

Wasp venom changes depending upon the type of wasp. Most have similar ingredients to the bee but the make up is different in the percentages of each ingredient.  One of the main differences between the wasp sting vs. the bee sting is the way the two   inject their venom.

The wasp thrusts his shaft into the victim and the lancets move rapidly backwards and forwards (sliding along the stylet) in a sawing action.  The lancets are barbed, meaning, they have small backward-pointed hooks along their edges.  As the shaft penetrates further into the victim's body, the barbs allow anchorage against the flesh until the alternate lancet moves forward and 'claws' the shaft deeper into the wound.  The movement of the lancets also enables a pumping action to take place at the abdomen end of the shaft.  This causes the poison sac to pump venom down through a central poison canal, between the lancets and out through the shaft tip into the wound.   Both Bees and Wasps sting their victims using a similar process but there is an essential difference, especially important when the victim being stung is a human-being.   Bee lancets have larger barbs than wasps.  The bee is unable to rip the shaft back out through the wound due to the barbs' resistance against the firmness of human flesh.   The wasp stinger has lancets with very small barbs, more like fine serrated edges.  A wasp can extract the shaft and fly off contented with having executed a nasty attack on the helpless victim.   On the other hand the poor old bee ends up having his entire stinging apparatus, poison sac and all, wrenched out of its abdomen.  The bee will later die due to the damage caused.

MUD DAUBER WASPS (Family Sphecidae)

Mud Dauber wasps are not social wasps like Paper wasps. They are in a different family. Many paralyze spiders to provision mud cells built to enclose eggs, larvae and pupae. The mud cells form long clay tubes or large lumps. The wasps are slender; they are shiny black or brown, orange or yellow, with black markings. Many have long slender thread waists.

Like Carpenter bees there is no protective worker caste; these wasps are not aggressive; they will not sting unless pressed or handled. Mud Daubers place their mud nests in protected places like electric motors, sheds, attics, against house siding and under porch ceilings. So many wasps congregate at the same site to construct the mud nests that later removal of the nests and repainting is often expensive.

HORNETS, WASPS, AND YELLOW-JACKETS

In parts of the United States, particularly in the eastern states, yellowjackets, wasps, hornets and bees are all called bees by the general public. Of course the general public is principally focused on one attribute these insects have in common -- their stingers.

Knowledge of the behavior of these pests is essential to their management; effective communication with frightened or, at best, fearful clients is an important skill technicians must develop.

Nests of stinging pests are usually the target for control. Understanding nesting and the make-up of the colony is essential.

NESTS AND COLONIES

Yellow-jackets, hornets and paper wasps are all in the same insect family, Vespidae. The common Paper wasp with its umbrella shaped nest or single comb best demonstrates the basic building pattern of a colony.

THE GIANT HORNET (Vespa crabro)

Technically, this wasp is the only hornet in North America, but it did not originate here; it was introduced from Europe. It is found in the northeastern quarter of the United States; it ranges as far south as North Carolina and Tennessee with scattered sightings extending west of the Mississippi River.

The Giant hornet is reddish-brown and yellow and almost an inch long. It builds its nest mainly in hollow trees, and in wall voids of barns, sheds and sometimes houses. An open window or door is an invitation to hornet workers, and they frequent buildings under construction. Their large combs and envelope are constructed of partially decomposed wood and, like the Eastern yellowjacket, are very brittle. Workers of the Giant hornet capture a variety of insects including bees and yellowjackets to feed their young. Workers also have a habit of stripping bark back from some shrubs -- especially lilac. As they girdle the branches, they lick the sap from the torn edge. They will sting humans, and the sting is painful.

PAPER WASPS

Paper wasp queens, like other Vespid nest mothers, is the lone female reproductive, who begins her nest by attaching a thick paper strand to an overhanging structure. She then builds hollow paper cells by chewing wood or plant fibers (cellulose) mixed with water and shaped with her mouthparts.

When a half dozen cells or so are hanging together, the Queen lays an egg near the bottom of each one. The little white grubs that hatch from the egg glue their rear ends in the cell and begin receiving nourishment in the form of chewed up bits of caterpillars provided by their mother. When they grow large enough to fill the cell cavity, they break the glued spot and hold on their own by their stuffed fat bodies, hanging head down.

Mature larvae, then, spin silk caps, closing off the cell, and molt into pupae. This same larval behavior pattern is followed by yellowjackets and hornets also. All are females. Other than their white color, these Vespid pupae look like adults; they develop adult systems, then shed their pupal skins, chew through their silk cell cap, pump out their wings, and take their place as worker assistants to their mother. (Paper wasp queens and workers are the same size; yellowjacket and hornet queens are larger than their daughters.)

From Spring on, the queen lays eggs and the daughter workers feed larvae and expand the comb or nest. They do not eat the protein (insect) food they gather for the larvae but get their energy from flower nectar. Later in the season, some of the larvae develop into males and others will become next year's queens.

The new males and females mate with those of other colonies, and the fertilized females find hiding places under tree bark or in logs and wait out the winter until they can begin their new colony in the spring.

The male Vespids die in winter, likewise the nest disintegrates and will not be used again.

YELLOW-JACKETS

Yellow-jacket (with eighteen species in North America) colonies begin with a large fertilized queen; she develops smaller daughter workers and later reproductives just as the Paper wasps, but the nest structure is not the same. Some yellow-jacket nests hang in trees and shrubs, and some are developed underground.

Aerial Nesters

Several yellowjackets make the aerial football- shaped paper nests, commonly called hornets nests. Two of these yellowjackets are common: the Aerial yellowjacket, Dolichovespula arenaria, and the Bald Faced hornet, Dolichovespula maculata.

The Aerial yellowjacket is found in the west, Canada, and east ( but not in the central and southern states). This species begins its nest in March or April and is finished and no longer active by the end of July. Their nests, usually attached to building overhangs are smaller and more round than those of other species.

The Bald Faced hornet is larger than the other yellowjackets and is black and white -- not black and yellow. It lives along the west coast, across Canada, and in all of the states in the eastern half of the country.

On warm spring days, the large Aerial nesting queen develops a small comb, like the Paper wasp with a dozen or so cells, but she encloses it in a round gray paper envelope. The daughter workers later take over the nest duties, and by mid summer, when the worker population is growing and food is plentiful, the nest is expanded to full size. A full-sized Bald Faced hornet nest consists not of a single umbrella comb like the Paper wasp, but four to six wide circular combs -- one hanging below the other and all enclosed with an oval paper envelope consisting of several insulating layers. Bald faced hornets not only gather flies, but are large enough to kill and use other species of yellowjackets for larval food. They attach their nests to low shrubs or high in trees or on buildings. Although Aerial colonies can have four to seven hundred workers at one time, their food gathering habits do not routinely bring them in contact with humans. Large nests are often discovered only after leaves have fallen and the nests are exposed -- both to view and to nature's elements that finally bring about their disintegration.

Underground Nesters

The stinging wasp, often identified as a yellowjacket, is black and yellow. Primarily yellow bands cover a dark abdomen. These species are in the genus Vespula.

They begin their nests like the aerial nesters -- with an enveloped small comb made of wood fiber paper. Only these nests are started in soil depressions, rodent burrows, or in any small hole in the ground that will give protection until workers can develop.

Once workers begin nest care, they enlarge the entrance hole and expand the nest. Combs are placed in tiers, one below the other. They can be very large; they have firm support from the soil surrounding the external envelope. Several species of Vespula make their nests in building wall voids, attics, hollow trees and other enclosed spaces as well as the ground.

Both Aerial and Ground Nesters

Of the thirteen species in North America, only a few require pest management. These few species have certain characteristics and habits that put them on a collision course with people:

•They can live in what might be called disturbed environments (areas that have been changed to suit human activities in urban settings) such as yards, golf courses, parks, and other recreation areas.

•They have large colonies -- some will develop thousands of workers.

•Their habits do not restrict them to a specific kind of prey. Foraging workers capture insects for their larvae and nectar and other sweet carbohydrates for themselves where they can find it. Essentially, they are scavengers and work over garbage cans and dumpsters. They especially enjoy picnics and football games.

One can easily see that these habits put a large number of foraging stinging insects into close association with large populations of humans.

THE COMMON YELLOWJACKET
Vespula vulgaris

V. vulgaris ranges across Canada and the northeastern United States. Common in higher elevations, it nests in shady evergreen forests around parks and camps in the western mountains and the eastern Appalachians. This species also is one of the most important stinging insects in Europe.

THE EASTERN YELLOW-JACKET (Vespula maculifrons)

This common ground nesting yellow-jacket is distributed over the eastern half of the United States. Its western border is from eastern Texas north to eastern North Dakota. Workers are slightly smaller than most yellow-jackets, but colony size can number around 5,000 or more individuals. The nest of V. maculifrons is dark tan, made of partially decomposed wood and is quite brittle. The Eastern yellow-jacket sometimes nests in building wall voids.

Most yellow-jackets have very slightly barbed stingers but the sting will not set in the victim's tissue like the barbed stinger of the honey bee. The stinger of V. maculifrons, however, often sticks and when the insect is slapped off, the stinger may remain.

THE GERMAN YELLOWJACKET (Vespula germanica)

In Europe, German yellowjacket nests are subterranean, but in North America the vast majority of reported nests are in structures. This yellowjacket is distributed throughout the northeastern quarter of the United States. Nests in attics and wall voids are large, and workers can chew through ceilings and walls into adjacent rooms. The nest and nest envelope of this yellowjacket is made of strong light gray paper. Colonies of this yellowjacket may be active in protected voids into November and December when outside temperatures are not severe.