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Order: Hymenoptera
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Common Name--Ants, Bees, and Wasps
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Names
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The order Hymenoptera is pronounced "hy-men-OP-ter-a." This
name comes from the words, "hymen," which is a Greek
word for membrane, and "ptera," which means wings. This name
is used because the forewings and hindwings of these insects
are membranous.
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Sawflies are wasps that get their name from the saw-like
ovipositor of the female. Velvet ants, also known as
cow-killers, are very hairy wasps that have wingless females.
Mud-daubers, potter wasps, and paper wasps get their names
from the materials and form of their nests.
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Diversity
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Hymenoptera is the third largest order of insects. There are
more than 103,000 described species in the world. Scientists
estimate that there are at least 200,000 species that have not
been named and described. More than 17,700 species are found
in North America.
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In North America, there are almost 1,000 species of sawflies.
Parasitic wasps include more than 9,500 species. There are
about 3,000 species of solitary and social wasps, 3,500 species
of bees, and 580 species of ants.
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Habitats
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Many Hymenoptera feed on plants, visit their flowers, or are
parasitic on other insects that eat plants. Some wasps, bees,
and ants live in the ground, and some build elaborate nests of
paper, mud, wax, or other materials. These nests can be found
hanging from stalks of grass or limbs of trees, under bridges
and eaves of houses, and many other places. Many ants live in
hollow stems or hollow thorns of plants.
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Form and Function
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Most Hymenoptera are less than one inch long, but some are
more than 5 inches long. Their bodies can be nearly hairless or
very hairy. Bees are unique in having hairs on their bodies that
are branched or feathery, which helps them carry pollen.
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Most species have two pairs of membranous wings. Each hindwing
has a row of hooks on the margin, and these lock onto the
larger front wing. Some of the smaller parasitic Hymenoptera
may have very small hindwings or be completely wingless.
Ant workers are wingless, but reproducing males and queens
have wings, which are lost after mating.
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Only females of some Hymenoptera can sting because the stinger
is the female's ovipositor. Honey bees are unique in having
barbs on their stingers. If a honey bee stings a person, the
stinger and venom gland are pulled from the bee's abdomen, and the
bee dies. Sawflies and parasitic wasps do not have a stinger
with venom glands.
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Hymenoptera have chewing mouthparts, often with large
mandibles in soldier ants. Bees also have a tongue-like
proboscis for taking liquid food. Most wasps and bees have
antennae with 13 segments in the male and 12 segments in the
female. Parasitic wasps can have from three to 60 segments
in their antennae.
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There are two main types of larvae in the Hymenoptera.
Larvae of sawflies resemble caterpillars. Sawfly larvae have
6-8 pairs of short prolegs on their abdomen, whereas
caterpillars of moths and butterflies usually have four or
fewer. Larvae of other Hymenoptera lack legs and are
grub-like.
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Life Cycle
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Hymenoptera have complete metamorphosis (egg, larva, pupa,
and adult). Females of some Hymenoptera can produce young
without mating. Mated females can control the sex of the
offspring. If the female allows the egg to be fertilized, it
becomes a female. If the egg is not fertilized, it becomes a
male. Some parasitic Hymenoptera have the ability to produce
many offspring from a single egg.
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The social Hymenoptera include ants, yellow jackets, hornets,
paper wasps, and some of the bees. Social species live in
colonies that include three main castes: queens, female
workers, and males. A queen mates with a male during a swarm,
or mating flight, and then finds a place to start a new colony.
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The honey bee queen may lay more than 2,000 eggs a day early
in the summer. Most of the eggs are laid in cells to make
female workers. A few unfertilized eggs are laid in special
cells to produce males, or drones. If the colony loses its
queen or prepares to swarm, larger cells are built for eggs
that will become new queens. Whether the egg becomes a worker
or queen depends on the food that the larva gets. Workers
nursing larvae have a gland near their mouth that makes "royal
jelly." All larvae are fed royal jelly for the first three
days after hatching. Larvae that become workers or drones
are switched to a diet of pollen and honey. Queen larvae are
kept on a diet of royal jelly.
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Honey bee workers have different tasks depending on their age.
After they become adults, the workers serve as nurses for the
larvae. Within a few weeks, these workers are able to make
wax and enlarge the comb. Older workers leave the hive to
gather pollen and nectar. Workers only live 5-6 weeks during
the summer, but workers produced in the fall will live through
the winter. A queen may live for 3-4 years.
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Food and Feeding Habits
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Some sawflies feed on leaves and flowers and some live inside
leaves, feeding as leaf miners. Wood wasps, which are
related to sawflies, are borers in trunks of trees. Many
cynipid gall wasps cause a plant to form galls, in which they
live and feed. Bees visit flowers to gather pollen and nectar,
which is used to make honey. Some ants, such as harvester
ants, feed on plant seeds that they store.
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About 65% of all Hymenoptera are parasites of other insects
and spiders. The parasitic wasp larva feeds on the host
insect or spider, eventually killing it. Some of the smallest
wasps are parasites of insect eggs. A parasitic larva inside
a host insect may become parasitized by another wasp. A
parasite of a parasite is known as a hyperparasite.
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Most of the stinging wasps are insect predators. Solitary
wasps paralyze their prey instead of killing it and store
this food in nests for their larvae. Social wasps, such as
yellow jackets and hornets, kill and chew the prey that they
feed their larvae. Many of these wasps eat particular kinds
of food - some prey on spiders and others on crickets, flies,
caterpillars, or other insect.
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Some ants are very aggressive predators. Army ants in the
tropics never have a permanent nest, but march from campsite
to campsite. At a campsite, large numbers go on raids to
capture other insects and small animals. Driver ants in Africa
are even more aggressive than army ants. A full grown leopard
in a cage was once killed and eaten by driver ants.
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Leaf-cutter ants are unique in the animal kingdom in their
ability to grow a special kind of fungus on freshly cut leaves.
These ant "farmers" cut pieces of leaves from a plant, which
they carry over their head to their underground nest. Inside
the nest, these leaves are placed in a "garden" where the
fungus will grow on them.
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Other ants feed on sugary foods, such as honeydew from
Homoptera, nectar from plants, and even drops of pancake syrup
in a kitchen. Ants that milk the honeydew from aphids often
protect their "herd" by building barn-like structures or by
driving off predators. Some ants will keep aphids in their
nests through the winter and put the aphids back on the plant in the
spring.
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Natural Enemies
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The greatest natural enemies of the Hymenoptera are other
Hymenoptera. There are a great number of wasps, ants, and
bees that parasitize or prey on other species in the order.
Some bees and wasps are called cleptoparasites because they
steal the food that has been stored for the larva of another
species.
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Frogs, birds, mammals, and many insects are natural enemies of
social Hymenoptera. Hornet nests are often torn apart by birds
that feed on the larvae. Bears are serious pests of honey bee
hives. Some frogs, like the narrow-mouth frog, feed primarily
on ants, and a single frog can eat more than 600 ants in one
day. Ants and their larvae are preyed upon by flies, beetles,
and other insects.
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Some mites (Class Arachnida) are very serious enemies of
certain Hymenoptera. The varroa mite is one of several kinds
of mites that are threats to the honey bee. There are also
fungal and bacterial diseases which can infect wasps, bees,
and ants.
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Olympic Feats and Other Strange Facts
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Potter wasps (family Vespidae) build pot-shaped mud nests in
which they store prey for their larvae. They use a special
glue that prevents the mud from dissolving in rain water.
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Some parasitic wasps (family Ichneumonidae) have very long
ovipositors with which they can penetrate more than an inch of
hard wood to lay their eggs on insect larvae boring in the
tree.
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The mymarid wasp, Caraphractus cintus, can swim under water to
parasitize the eggs of diving beetles.
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The queen of a leaf-cutter ant mates only one time in her life,
but she can produce up to 300 million offspring over a 15-year
period.
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Ants are believed to make up 10% of the total weight of all
animals in the world.
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On the Ivory Coast of Africa, 8 million ants have been found
in one acre of savanna.
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The Japanese ant, Formica yessensis, have large and
interconnected colonies. One such "supercolony" had an
estimated 1,080,000 queens and 306,000,000 workers in 45 nests.
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The oldest known ant, Sphecomyrma freyi, is a specimen
found in amber which lived 100 million years ago during the
mid-Cretaceous period.
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A harvester ant has been seen lifting a pebble that weighed 52
times as much as the ant. This would be equal to a 160-pound
person lifting more than four tons.
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Honey bees saved the city of Chester, England in 908 AD from
an army of Danes and Norwegians. The invaders were digging
under the foundations of the city's walls when the city's bee
hives were dropped on them, driving them away.
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Honey bee workers provide air conditioning for their hives by
bringing in droplets of water and fanning their wings at the
entrance of the hive.
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Honey bee workers do much traveling to gather nectar to make
honey. In order to make a pound of honey, honey bees have to
travel a distance equal to going twice around the world.
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Honey bees use a "dance language" to communicate distance and
direction of nectar sources to other bees. The waggle dance
is explained in
Basic Facts: Insect Communication.
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Fairyflies (family Mymaridae) are parasites of insect eggs and
are 0.007 inch long and small enough to fly through the eye of
a needle.
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Some digger wasps in the genus Ammophila, use pebbles as tools
to pound the area around their nest entrance so as to make it
look like there is no entrance at all.
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In a study of the spiders captured by the blue mud-dauber in
Louisiana, nearly 100 black widow spiders were found in just
five nests.
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The Good and The Bad
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Larvae of some Hymenoptera, such as conifer sawflies and birch
leaf miners, are serious pests of trees. Stem sawflies are
pests of wheat. Carpenter bees and carpenter ants may bore
into the wood of houses and other structures.
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Most people who work or relax in the outdoors have suffered
the stings of ants, bees, and wasps. More people die every
year from stings of Hymenoptera than from bites of snakes,
usually as a result of allergic reactions to the insect's venom.
On the positive side, bee stings have been used as a remedy for
rheumatism and for other medical treatments.
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Many ants can be a general nuisance, and a picnic probably
would not be complete without an invasion of ants onto the
table. A positive side of ants is their role in turning over
much soil in digging their nests, which improves the soil's
fertility for better plant growth.
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Parasitic wasps provide natural control of insects that are
pests on crops. Some parasitic wasps are obtained from
one country, raised in laboratories, and released for
biological control in another country.
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Honey bees are raised commercially by man and provide us with
honey, royal jelly, and wax. The raising of bees, which is
called apiculture, is a multi-million dollar industry that
greatly helps the economy. The honey bee and other
kinds of bees are pollinators of many crops upon which people
depend.
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Taxonomy
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Selected Families of North American Hymenoptera
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Diprionidae (conifer sawflies)
Tenthredinidae (common sawflies)
Cephidae (stem sawflies)
Siricidae (horntails)
Braconidae (braconid wasps)
Ichneumonidae (ichneumon wasps or flies)
Trichogrammatidae (trichogrammatid wasps)
Chalcididae (chalcid wasps)
Cynipidae (cynipid wasps)
Scelionidae (scelionid wasps)
Platygastridae (platygastrid wasps)
Chrysididae (cuckoo wasps)
Sphecidae (sphecid wasps)
Halictidae (sweat bees)
Megachilidae (leafcutting bees)
Anthophoridae (cuckoo, digger, and carpenter bees)
Apidae (honey, bumble, and orchid bees)
Mutillidae (velvet ants)
Pompilidae (spider wasps)
Vespidae (paper wasps, hornets, yellow jackets, and others)
Formicidae (ants)
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Selected References
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Evans, Howard E. Wasp Farm. Garden City, New York: The
Natural History Press, 1963.
Holldobler, B. and E. O. Wilson. Journey to the Ants.
Cambridge, Massachusettes: Belknap Press of Harvard University
Press, 1994.
Hutchins, Ross E. A Look at Ants. New York: Dodd, Mead,
& Co., 1978.
Newman, L. Hugh and Stephen Dalton. Ants from Close Up.
New York: Thomas Y. Crowell Co., 1967.
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Links
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For an extensive list of Hymenoptera Web sites, go to the
Links Component
of the module.
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Picture Credits
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Dr. Ross E. Hutchins (Deceased)
Mississippi Entomological Museum
Colobopsis ant blocking entrance to hollow stem
Bumble bee with hairy body
Mandibles of Australian bulldog ant
Yellow jacket queen and workers on nest
Honey bee queen and workers
Gall enclosing larva of cynipid wasp
Parasitic wasp and aphid host
Mud dauber larva and paralyzed spiders
Army ant cluster at a camp
Leaf-cutter ants returning to nest
Ant barn for scale insects
Cuckoo wasp, parasite of mud dauber
Potter wasp with mud nest
Queen of leaf-cutter ant
Ant lifting pebble 52 times its weight
Cocoons of wasps emerging from hornworm
Dr. Robert Tisdale
Department of Entomology
Mississippi State University
Neodiprion fulviceps sawfly laying egg
Sawfly larva in defensive posture
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