FEBRUARY
2002

 

 

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

 

 

 

 

2-28-02

Most Insects Exhibit Poor Parenting Skills

In the animal world, parenting is something that comes naturally. It's in the genes. Mammal mothers, like deer, dogs, sheep and cows, lick the newborns and nuzzle them into position to nurse. We call it "maternal instinct."

Adult birds brood the eggs and carry food to the hatchlings in the nest. At night, the mother provides the young with warmth and protection.

In the case of predators like foxes, the parents even teach the young to hunt. The same is true of birds. Outside the nest, the adults show fledgling birds the finer points of rustling up a meal. That is what the clucking and scratching of a mother hen with a brood of chicks is all about. The hen is teaching the chicks how to find food.

While parenting comes naturally to most creatures, the two most successful animals on Earth aren't good at it. Humans and insects rank up there among the worst parents in the animal world.

Of course, calling humans and insects poor parents is a value judgment. After all, both groups are highly successful animals. But humans seem to have to learn to parent. Otherwise, why would we buy so many books on parenting? Since Dr. Spock pioneered such books, literally dozens of titles on the subject have appeared on booksellers' shelves around the world.

Insect parenting varies from minimal input to a sophistication that even we highly evolved humans try to emulate. Most insects leave their offspring to fend for themselves, but even these try to give their kids a good start in life.

The simplest approach to the insect version of child rearing is to do nothing. Some insects simply drop eggs as they feed. Such is the case with some walking sticks that drop their eggs from the trees. Some cockroaches deposit their egg cases, called ootheca, as they run along. Mayflies actually lay eggs as they die, wherever that may be.

A common insect approach to bringing up junior is to place the eggs in a desirable location. That generally means in a place where the newly hatched insect will find food. For instance, many butterflies and moths will fly around looking for a suitable food plant for their offspring. When the female finds such a plant, she will lay an egg. When the egg hatches, the caterpillar doesn't have to move far to find food.

Sometimes the egg is just placed among food items. Ladybug mothers-to-be deposit their eggs close to aphids. Since ladybugs and their immatures feed on aphids, the baby ladybug is normally surrounded by potential meals.

Many flies feed on dead or decaying plant and animal matter, so the eggs are laid on--you guessed it--dead stuff. That explains why you see flies buzzing around road kill; many are laying eggs. The resulting maggots begin feeding on the rotten flesh.

Placing the eggs in a desirable location by insects would be equivalent to humans leaving their children in a fast-food restaurant. The food would be there; the kids would have to find it.

Some insects provide the kid's food in bulk--enough food to meet the lifetime needs of the immature. The mud dauber wasps that provision the nest with spiders or caterpillars use this approach. Enough of the prey items are placed in each cell to feed the larvae. Cicada-killer wasps provide a single cicada for each wasp larva. Leaf cutter bees and carpenter bees store enough pollen in a nursery cell to meet the needs of each baby. This would be like a human parent giving a lifetime certificate for the fast-food restaurant.

Some insects, like the paper wasps, supply food as the offspring need it. They are called "progressive provisioning insects" and could be compared to humans who provided coupons for food as needed.

Some insects actually turn over the whole process of feeding the offspring to workers specialized in child care. This is the way of life for social insects, like ants, termites, bees and wasps. In this case, the workers prepare the food and feed the kids. Sounds very much like a family that hires a nanny to care for the kids, doesn't it?

 

Writer: Tom Turpin
Editor: Olivia Maddox