Forest Preserve District of Cook County (Illinois)
Nature Bulletin No. 467-A OPctober 21, 1972
Forest Preserve District of Cook County
George W. Dunne, President
Roland F. Eisenbeis, Supt. of Conservation
****:HORNETS, WASPS AND YELLOW JACKETS
Wasps and bees and ants make up a group which occupies top place on
the family tree of the insect world: partly because of their complicated
anatomy but mostly because of the built-in-automatic features of their
behavior which many people mistake for intelligence. Their elaborate
ways of housing and feeding their young, or the division of labor among
members of their colonies, do not signify intelligence. They merely
inherit these instinctive traits.
The wasps include a multitude of kinds ranging in size from parasitic
species almost invisible to the naked eye and reaching their full growth
inside the tiny eggs of other insects, up to the giant Cicada-killers. Most
kinds are so small or so scarce that they are seldom seen or recognized
by ordinary people, but there are four types familiar to most of us in the
middle west.
The Mud Daubers or "solitary wasps", the White-faced or "Bald-headed
Hornets, the Yellow Jackets, and the Paper Wasps, rear their young in
cells which are as precisely engineered as those in a honeybee comb but
are made of mud or paper instead of wax. The last three are called
"social wasps " because of their caste systems and the division of labor
within their nests. Unlike bees, they feed their young on animal matter
instead of nectar and pollen from flowers. We avoid wasps because a
female defends her nest with a painful stinger and, unlike a honey bee,
she can sting many times.
The common blue-black Mud Dauber typifies our expression "wasp-
waisted" because its abdomen is a mere knob at the end of a long
slender stem. As a female gathers mud and then trowels it into place at
the chosen nest, she seems nervous, fidgety, and constantly jerks her
iridescent wings. One by one, the tube-like mud cells are completed,
stuffed with captured spiders, and egg placed in each, and then sealed.
Each spider is paralyzed by a sting precisely placed so that it will
remain inert but alive until the wasp's grub hatches out and needs it.
When fully grown, the plump whitish grub weaves a silken cocoon
inside the tube and changes into a pupa. Some emerge as adults that
season; others in spring.
The other three familiar types, social wasps, are the world's finest
papermakers. They chew up bits of weathered wood, waste paper and
cardboard to build many-celled combs of tough membranes. The queen
of the colony lays an egg in each cell. When it hatches, the grub is
constantly tended and fed on chewed-up insects -- first by the queen;
later by infertile female workers.
Hornets build an egg-shaped nest, often a foot in diameter, anchored on
a branch of a tree or shrub, with many tiers of combs enclosed in sheets
of gray flaky paper, and an entrance at the bottom. A Yellow Jacket's
nest is similar but smaller and located in an old mouse nest
underground, in a stump, or in a brushpile. Most commonly seen are the
exposed unbrella-like combs of the Paper Wasp suspended, by short
stems, under the eaves of houses or inside barns, sheds, and other
sheltered places.
Among these social wasps, as with the bumblebee, only fertile queens
survive the winter, and not in the old nest but hidden away in the walls
of buildings, hollow trees, crevices under the bark of trees, or among
trash. In spring she starts a new nest with a few cells which produce
workers. Gradually, they take over and the queen is free for her main
job of laying eggs. Later, certain grub are fed special diets so that some
will develop into young queens. Males or drones come from
unfertilized eggs.
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