Unit 8 in Entomology
Unit eight, Insect Sociality.
The objectives of this unit are to describe the characteristics of subsocial and eusocial insect behavior.
We will also compare and contrast the life histories of ants and termites.
We will define trophallaxis,
pseudergate, caste, and halpodiploid and explain superorganism and how insects are so successful.
Social behavior involves cooperation between individuals of the same species and the degree of that
cooperation defines the type of sociality that species demonstrates.
We as humans are social animals
and insects are actually used as models of social behavior.
You've learned about many of the different
insect orders, can you think of any that you would consider to be social?
In fact, only about 2% of all
insects are social.
Before we get ahead of ourselves let's define the different categories of social
The two categories we’ll discuss are eusocial and subsocial behavior.
Sub means below, and the prefix
eu means true.
Well, insects interact with each other, even if it's just to come together to reproduce.
The degree of their interaction places them in a category of social behavior.
Some of the terms we have
here may be new to you, so if you have a question, be sure to look up the term in the glossary of your
So a subsocial insect would have the behavior of either aggregation or a division of labor or
they would care for their eggs or their young after the eggs were laid.
And truly social insects are
They have cooperative brood care, which means that they cooperate to take care of
the babies, kind of like a daycare center.
They also have overlapping generations so they will have
grandparents, parents, offspring in multiple generations living together.
They also have reproductive
division of labor, so it's a caste system, where some groups will only reproduce, some groups will care for
the young, some groups will work, etc.
Were you able to think of any social insects before?
Well, let's take a look at some examples.
examples of subsocial insects are cockroaches, crickets, earwigs, praying mantids, webspinners, plant
There are nine families of true bugs, 13 families of beetles, and certain wasps and bees.
There are fewer species of eusocial insects: the termites, bees, wasps, and ants are all truly social with
the caste system, reproductive division of labor and cooperative brood care.
If you take a look at the
pictures to the right, you'll see at the top right corner there's a giant water bug, and the female will actually
deposit her eggs on the back of the male and the male will carry the eggs around until they hatch.
that is a subsocial behavior, which is care for young after the eggs have been laid.
On the bottom right is
a picture of an assassin bug and the adults will actually guard early instar nymphs to protect them from
Again, a subsocial behavior.