Insect
| Insect |
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| Scientific Classification |
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| Orders |
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Subclass: Apterygota
Subclass: Pterygota
Superorder: Exopterygota
Superorder: Endopterygota
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Insects, according to creation science, were created on the sixth day of creation along with all other land animals and man. They are the most copious and widespread terrestrial taxon in the phylum Arthropoda. There are about 925,000 identified species, with the total estimated number somewhere between two and thirty million. Insects can be found in almost all environments making it the most diverse group of animals on earth. Small species have even habituated life in the ocean. The sizes of adults also vary greatly. Some are as small as 0.139 millimeters and others as large as .5 meters. The study of insects is called entomology from the greek word meaning "cut into sections".[1]
Anatomy
All insects have an exoskeleton, an external supporting structure. Their bodies can be divided into three major parts: head, thorax, and abdomen. The head is where the mouthparts, eyes, and antenna are located. The thorax supports three pairs of legs and usually two pairs of wings. Some insects don't have wings, i.e. ant and termite. The abdomen stores the digestive system and reproductive organs.
The most distinctive part on an insect's head is its mouthparts. Some are designed for chewing food and others are designed for sucking it up. The butterfly sucks up its food through a part of the maxillae that forms a tube. The common house fly has a mouth like a sponge, it "mops" up its liquid food. The mosquito also uses its mouth like a siphon to ingest food. All mouthparts, except for the labium, form a needle-like tube called a facile. The ground beetle uses large mandibles in order to pierce and cut its prey.
All insect legs are made of the same primary parts; femur, trochanter, coxa, tibia, and tarsus. However some insects differ substantially. There are many different types of legs like those of a cockroach which are made for running, or those of a fly which have tiny pads with some sort of adhesive which allows it to climb upon walls. Some insects have very strong muscular legs which can be used for jumping great distances e.g. grasshopper.
Insects use antennae as a sensory structure. It allows them to find out more about its surroundings. There are a few different varieties of antennae. There is the cockchafer, moth, and mosquito antenna, which allow more surface area for sensory cells. And the bee antenna is more simple.
Most insects have membranous wings. Many have a system of thickened lines in the wings, called venation. However the wings of the butterfly and the moth are not membranous, they are covered with small dust-like scales.
Flies and mosquitoes have only one type pair of wings. And some species of insect are wingless i.e. ant, termite. Most insects actually have two pairs of wings. The wings can be as obvious as the lacewing fly or the butterfly wing, but others may be more discrete or hidden. Some insects, like the beetle, even have a covering that protects the wings when they are not being used.[2]
Reproduction / Life Cycle
Insects have separate sexes, and they reproduce sexually. Some insects' eggs however are developed without fertilization by sperm. In a few species of insect, like the bee, unfertilized eggs become the male and fertilized eggs become the female. Other species produce all female eggs by parthenogenesis. Parthenogenesis is the fertilization of eggs without sperm. The eggs are most often laid in as sheltered place. A couple of species of insect actually keep the egg inside their body and hatch it before it is released. After being hatched the insects molt periodically as it grows. The reason it must molt is because as the insect grows, but the exoskeleton does not. And before they start molting a new soft exoskeleton is formed. Just after the insect molts its body rapidly grows before the new exoskeleton hardens.[3] Molting is also called ecdysis, and the intervals between molts are called instars.
The life cycle of winged insects (pterygote) is a lot more complex than that of wingless insects. The insects that come from eggs is usually completely different from the adult stage. The most obvious distinction is the lack of wings. The features, mouthparts, and legs are different as well. The young pterygote must go through considerable changes before it reaches its adult stage. This process is called metamorphosis.
Winged insects are categorized into two groups, according to how their wings develop during the young stages. The first group consists of insects like cockroaches, grasshoppers, and dragonflies. The wings develop slowly outside of the body and get larger at each molt. The young stages of these insects are called nymphs. Nymphs are, most of the time, like a smaller image of the adult. These insects are classified as Exopterygota. This refers to the external development of the wings. They undergo what is called a simple metamorphosis, on account of the fact they have no dramatic body changes.
The second group of insects consists of beetles, butterflies, moths, flies, bees, wasps, etc. The adolescents of this group are considerably different from the adult and are referred to as larva. Examples of larva include grubs, caterpillars, and maggots. The larvae later matures into adult forms such as bees and wasps, etc., grubs turn into beetles, caterpillars turn into butterflies and moths, and maggots turn into flies. They often inhabit different habitat niches and thrive off of a completely different food than that of which the adults eat. Instead of going through an array of small changes in order to achieve full maturity, they sustain a single dramatic change that needs a special resting stage. During this stage they do not consume any food while this transformation occurs. This resting stage is known as the pupa. In this group the wings grow internally and cannot be seen until the pupal stage is almost complete. The classification of this group is Endopterygota. The insects in this group are said to have gone through a complex or complete metamophosis, because its large transition from a larva to an adult.[4]
Ecology
Don't you hate it when your sitting in your classroom or house you get a pesky bee or fly buzzing around you. Or maybe you're out in a tall grassy meadow and you see several different types of butterflies, and maybe the occasional praying mantis. You could be walking through the woods and accidentally step on a beetle, or see a dragonfly whizz past your face. Do you remember as you were younger and you sat on top of an ant hill with a magnifying glass? My point is that insects are all around you, no matter where you go you will see insects. But have you ever asked yourself why you don't see insects during the winter? Well this is what I'm going to share in this article.
Most insects don't actually disappear during winter. Insects have devised certain ways to survive even though they are cold-blooded. Many insects go through winter during the egg stage, the egg provide perfect protection against the harsh winter temperature. The eggs have shells that are thick and water-tight, in some cases the egg is covered in hairs, silk, or frothy materials, these insulate the eggs even more. Other insects go into a form of hibernation known as diapause. During this process insects undergo a deep sleep, which reduces the need for the body to use energy. The length of diapause is controlled by length of daylight hours, as opposed to the conditions of the environment. This keeps the insect from waking up during the warm temperature spikes during winter. Insects can hibernate whether they are adults or adolescents. Some insects dig into soil or bore into wood in order to escape the harsh winter months. Insects that hibernate as a pupa usually cover themselves with an insulating cover of silk. This kind of covering is known as a cocoon.
Insects that go through winter as an adult find shelter. They seek shelter in places like a hollow tree, logs, leaf piles, nests, or soil (warm places). Since they are completely grown they are always first to be seen in the spring. This is why the mourning cloak butterfly is one of the few butterflies you see out first in the spring. Some insects actually use our home as their source of protection from the winter. Even though our homes are warm most of the insect that live there still go through diapause.
Few insects migrate south during the winter months. The best example of insects that do migrate south for the winter is the monarch butterfly. Monarchs from all over North America go to Central America or southern California. The butterflies that go to central Mexico usually tend to be from east of the Rocky Mountains. Butterflies from west of the Rockies tend to migrate to southern California. In spring the butterflies return to North America.
A few insects however are active all year. Many aquatic insects, at immature stages, are able to survive all year. Some insects are actually only active during the winter. Adult winter stoneflies are active only during winter and early spring months. Also snow fleas and winter scorpion flies are only active during winter. Most of the insects active during winter have special body fluids that keep them from freezing.[5]
Gallery
Silverfish
(Lepisma saccharina)
Order: ThysanuraMayfly
Order: EphemeropteraBrown-banded cockroach
(Supella longipalpa)
Order:BlattodeaPraying mantis
Order: MantodeaEarwig
Order: Dermaptera,Stonefly
Order: PlecopteraGrasshopper
Order: OrthopteraWalking stick
Order: PhasmatodeaBarklouse
Order: PsocopteraThrip
Order: ThysanopteraLouse
Order: PhthirapteraSnakefly
Order: RaphidiopteraAlderfly
Order: Megaloptera(Ascalaphus libelluloides)
Order: NueropteraBeetle
Order: ColeopteraScorpionfly
(Panorpa communis)
Order: MecopteraFlea larva
SiphonapteraDeath skull fly
Order: DipteraCaddisfly
Order: TrichopteraButterfly
(Polyommatus icarus)
Order: LepidopteraAnt
Order: Hymenoptera
References
- insect wikipedia
- introduction to insect anatomy einsteins-emporium
- reproduction info please
- insect life cycle Kendall Bioresearch Services
- where do insects go in winter Topics in Insect Ecology