APRIL
2004

 

 

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

 

 

 

 

04-22-04

Being a Single Mother is Difficult, Even for Insects

In the animal world, parenting is generally not a team thing. Rearing offspring is frequently left to the mother. But there are exceptions. Mothers and fathers of many bird species share the duties of feeding offspring. Some bird fathers-to-be even contribute to incubating eggs.

Males of a few other organisms also help raise junior. Some male fish guard the nest where the eggs are deposited. One insect, a giant water bug, carries the eggs on his back until they hatch. Not willingly, however. That system is based on a female catching a male and gluing the eggs to his back. She doesn't even care if it is the father. Any male she can catch is given the job.

Most insects don't provide the slightest bit of child care. The kids are on their own as soon as they hatch. Social insects are an exception. Ants, termites and some bees and wasps take good care of their children. These insects provide what is known as brood care. They feed the young throughout their immature lives.

In most instances, brood care among the social insects is provided by a worker caste. These workers are aptly named, for they provide the labor in the colony. One of their major jobs is that of nursemaid for the baby insects. In permanent colonies of social insects, such as the termites, ants and the honey bees, there are always workers in the colony. 

There are other social insect colonies that are not permanent. Such colonies exist only during the growing season. The familiar bumble bee has an annual colony. So do all of the social wasps, such as yellow jackets and bald-faced hornets. Social insect colonies, which exist only for a single season, are started each year by a single mother. That mother is a mated queen that has spent the winter in hibernation.

It is not easy being a single mother, either for humans or for social insect queens. Here's how it works in the insect world. First, the mother-to-be must find a suitable home. If she is an ant queen that emerged from an ant hill, she searches for a nice place to get into the soil. Once the queen ant finds an acceptable location, she chews off her wings. The wings functioned during the mating flight and finding a home but will just be in the way in the close quarters of an underground ant home. She uses the energy provided by absorbing the wing muscles to produce enough food to feed the first few larvae. Once the larvae become ants, they will begin to gather food and feed the immatures. Then, the queen concentrates on egg laying.

A queen bumble bee that overwinters also flies around in the spring looking for a protected place to raise a family. The right place could be in a straw pile, behind a stack of wood, in a wall void or even an abandoned mouse nest. Like the ant, she will also lay a few eggs. The queen bumble bee will then collect pollen and nectar to feed her first-hatched kids. She doesn't do a very good job of child rearing and doesn't feed them the best; they turn out stunted. That is why many of the first bumble bees of spring appear small. Once the stunted, first few bees take over the child-rearing activities, the quality of the food increases, and the better-fed bees emerge larger.

Social wasps are much like bumble bees in the way the nest is established. The mated queens spend the winter hidden in the leaf litter of the forest. Come spring, they seek out sites to start construction of their paper nests. Yellow jackets build their nest in the ground, while bald-faced hornets attach their nests to limbs of trees. Paper wasps prefer a nest site located under the eves of buildings. 

Regardless of the location, the new mother does all of the work raising the first few offspring. And, then, she turns it over to the eldest children. That's kind of the way it works in large human families -- the bigger kids take care of the little ones!

 

Writer: Tom Turpin
Editor: Olivia Maddox