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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?
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