The Wondrous Wowbug
By Robert W. Matthews and Janice R. Matthews
T
hey seem almost too good to be true—
Where do wowbugs fit into
harmless living creatures that:
nature?
• Survive in a desk drawer for weeks
without food or water;
For an answer, step backward a bit. Most
• Multiply so rapidly that every student
people have seen mud structures like these
can have several;
on the walls of buildings (see Figures 1
• Naturally occur outdoors and are also
and 2). Long before houses and picnic
inexpensively available through com-
shelters, they appeared on rocks in loca-
mercial channels;
tions protected from rain and sun. They
• Demonstrate many fundamental con-
are nests of a group of harmless “solitary”
cepts—the most important aspect for
wasps—the mud daubers. each female
classroom use.
builds her own nest. Solitary wasps never
cooperate in nest building and defense the
These are wowbugs, Melittobia digitata.
way that “social” wasps, such as hornets or
As scientists, we have studied them in our
yellowjackets, do.
laboratory for over forty years. About fif-
In each chamber inside of her nest, a
teen years ago, we also began to introduce
female lays an egg a on paralyzed spider
these little insects into the school classroom
that will serve as larval food. Then she
and curriculum. Now we’d like you to meet
flies away, trusting that the nest’s thick
them, too.
mud walls will protect her eggs, but ene-
mies soon close in.
Predation and parasitism can be
intense—when one of our colleagues
opened a large series of mud dauber nests
from Missouri, Mississippi, and Alabama,
other insects had attacked and killed the
immature mud daubers in almost half of
the cells—and the most important of these
enemies are parasitoids that kill larvae by
feeding on them. The most common of
them all is the wowbug, Melittobia digi-
tata, a little wasp no bigger than an ant or
a fruit fly.
Figure 1
Parasites and Parasitoids: some terminology
Parasites are living organisms that feed in or on other living organisms
(hosts), usually without directly killing them. Tapeworms and ticks are
familiar examples upon humans and vertebrate animals, but true para-
sites of insects are poorly known.
To insects, parasitoids are the more widespread and important type
of enemy. Although they are generally smaller than their host, parasit-
oids are more like predators because they actually kill and consume it.
Parasitoids are the organisms most often used in natural pest control
methods such as so-called “biological control.”
Figure 2
page 8 • Connect © synergy learning • 800-769-6199 • March/april 2010
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