Insects may be small, but they are vitally important to our life here on Earth.
WHEN it comes to bugs, we are seriously outnumbered. Ninety-five percent of all the animal species on our planet are insects. Millions can exist in the smallest of spaces. Although more than a million species have been discovered by scientists, millions more are still unknown.
Insects are coldblooded and are, divided into 32 orders, or groups, the largest of which are beetles. This group alone contains 125 different families and 500,000 different species. Just how many is that?
Consider that one in every four animals on Earth is a beetle. Social insects, such as bees and ants, make up 20 percent of the total animal biomass on Earth.
That’s a lot of mouths to feed. Insects eat more plants than any other creatures on Earth. This is important, because they also break down plant and animal matter.Without insects, we’d be covered with dead animals and plants. Insects also are a major food source for other animals.
These little critters are extremely adaptable, which is why they have survived so long. They live everywhere, from the desert to the rainforest, and in every climate, from the tropics to icy Antarctica.
The insect’s body beautiful
As diverse as insects are, they have a few things in common. Each has:
* Three body parts: head, body and thorax
* Six jointed legs
* Two antennae
* An exoskeleton (hard outside skeleton)
Insects have an open circulatory system inside their bodies, meaning that fluids just flow around inside. There are also many breathing tubes and a digestive system.
Insects have a heart, but few blood vessels, due to the open circulatory system. Air enters through openings in the exoskeleton called spiracles. The breathing tubes take the oxygen all over the body.
The stomach is a long tube divided into three sections. Insects have a nervous system that sends and receive messages to and from the brain.
Reproduction
There are usually more females than males. In some species, the partners are around only during mating season. Some insects, like aphids, can change sex when too few or too many of either sex is available.
Most insects lay eggs, but some eggs hatch inside the female and are born live. Sometimes, they lay eggs on other insects, which then become unwitting hosts and eventually die as the young parasites eat away at them. Such is the case with the spider wasp.
It’s a bug’s life
Insects develop in four separate stages; egg, larva or nymph, pupa and adult. As the larva or nymph develops, it sheds its outer skin for a new one. All the growing is done during this time. Pupae and adults don’t grow.
The nymphs look like adults, but they don’t have wings yet.
Notice that spiders are not insects, because they have eight legs and two body parts. Centipedes and millipedes have too many legs.
Insects have been successful survivors because they reproduce quickly and in large numbers. They are small. They have a protective exoskeleton; and many can fly.
We couldn’t survive without our buggy friends. They clean up our planet and provide food for other animals and for us. They also provide us with silk, wax and honey.
Spring is here and the bugs are out. Although some – like flies, mosquitoes and cockroaches -might annoy you, most are helpful, and they all have their place on our planet.
Today’s page fulfills the following standards:
ELA 1c, 3c, 3d, 5a, Science 2a, 2b, 2c, 2d, Art Standard 2