Characteristics of class Insecta Body plan A CLASS OF DISTINCTION Number of species Number of individual Distribution REASONS FOR SUCCESS Exoskeleton small size Flight Reproductive potential Metamorphosis Adaptability Locomotion

IMPACT OF INSECTS Insect as food Ecological Impact Products of beneficial insects Examples of important orders of class

insecta(Diptera,Hemiptera,Hymenoptera,Lepidoptera, Orthoptera)

SOCIAL INSECTS Eusocial insects Types of ants Types of social wasps Forensic Entomology

-**3 body segment (head, thorax, and abdomen)-3 pairs of walking legs-Respire by trachea-Diecious-**Excrete through malphigian tubulesExamples of the class Insecta include the Grasshopper, Flies, Bees, Wasps, Hornets, Butterfly, Beetles, Praying Mantis, and Waterbug

BeetleClass InsectaPhylum ArthropodaKingdom Animalia

The Praying MantisClass InsectaPhylum ArthropodaKingdom Animalia

Sadly, the earth would probably be better off without us.

In simplest terms, life (as we know it) exists on planet earth because of a global cycle of production and consumption that hinges almost exclusively on green plants as primary producers and insects as primary consume

We humans are such a self-centered species that we seldom stop to acknowledge or appreciate the importance of other living organisms in our environment.  

Our prowess in science and technology has given us unparalleled control over our physical environment, and as a result, we have developed an inflated view of our own importance in the web of life. 

Without insects and other decomposers, green plants would quickly exhaust their nutrient supplies, dead organic matter would accumulate in putrid, rotting heaps, and many species of flowering plants would become extinct for lack of insect pollinators.

We expend considerable resources trying to eliminate these animals from every facet of our daily lives, but in fact, we could never hope to survive without them -- they make the earth habitable for us. 

By virtue of their diversity, their world-wide distribution, their ecological importance, and their impact on other life-forms, the insects are indeed a class of distinction.

THE DOMINANCE OF INSECTS

Entomologists describe hundreds of these new species each year, and still estimate that only one-half to one-third of the earth's total insect fauna has even yet been discovered.  In the final analysis, two of every three living species may be insects.

In fact, the insects are so numerous that if they were divided equally among each one of the earth's 6 billion human inhabitants, each of us would be allotted 1 x 1018 insects -- that's a billion billion -- 1,000,000,000,000,000,000.

As a "suit of armor", the exoskeleton can resist both physical and chemical attack.  It is covered by an impervious layer of wax that prevents desiccation.  Much of the exoskeleton is fabricated from chitin, a polysaccharide that binds with various protein molecules to form a body wall that may be as flexible and elastic as rubber or as hard and rigid as some metals

Most species are between 2 and 20 mm (0.1 - 1.0 inch) in length, although they range in size from giant moths that would nearly cover your computer screen to tiny parasitic wasps that could hide inside the period at the end of this sentence.

Insects are the only invertebrates that can fly.

Flight gave these insects a highly effective mode of escape from predators that roamed the prehistoric landscape. 

The migratory locust, Schistocerca gregaria, can fly for up to 9 hours without stopping. 

Reproductive success is one of the most significant measures of an organism's fitness

In insect populations, females often produce large numbers of eggs (high fecundity), most of the eggs hatch (high fertility), and the life cycle is relatively short (often as little as 2-4 weeks).

In the class Insecta, only 9 out of 28 orders undergo complete metamorphosis, yet these 9 orders represent about 86% of all insect species alive today. 

The obvious advantage to this type of development lies in the compartmentalization of the life cycle. 

Perhaps the most remarkable example of insect adaptation in this century has been the speed with which pest populations have developed resistance to a broad range of chemical and biological insecticides. 

Indeed, the capacity for independent, goal-directed movement is one of the distinguishing characteristics that sets animals apart from most other forms of life on this planet.

They have a direct impact on agricultural food production by chewing the leaves of crop plants, sucking out plant juices, boring within the roots, stems or leaves, and spreading plant pathogens.  They feed on natural fibers, destroy wooden building materials, ruin stored grain, and accelerate the process of decay.

Insects were undoubtedly an important source of nutrition for our early human ancestors.  Even today, they are still collected and eaten by people of many cultures.

Indeed, we seldom stop to consider what life would be like without insects and how much we depend on them for our very survival.

So far, over 6000 insect species have been tested and released as biological control agents to fight insects and weeds that we regard as pests.  But there are also countless other species that work for us as population regulators, often unnoticed until they are accidentally destroyed by a natural disaster or human intervention.

Phylum Arthropoda

Subphylum Uniramia

Class Insecta Order Diptera common Fly

Phylum Arthropoda

Subphylum Uniramia

Class Insecta Order Hemiptera common True bug

Phlyum Arthropoda Subphylum

Uniramia Class Insecta Order

Hymenoptera Common – bees,

wasps, and ants

Phylum Arthropoda

Subphylum Uriramia

Class Insecta Order Lepidoptera common – Moths

and butterflies

Phylum Arthropoda Subphylum Uniramia Class Insecta Order Orthoptera Common-

Grasshoppers, crickets, walking sticks, praying mantis, cockroaches. 

The biomass of ants and termites exceeds that of all other animal species combined; in the African savanah, a single colony of driver ants may contain as many as 20 million workers;

In Japan, a supercolony of Formica yessensis with 45,000 interconnecting nests contained more than a million queens and 306 million workers within an area of 2.7 square kilometers.

In order to qualify as eusocial, a species must exhibit all four of the following characteristics:

Share a common nest site Individuals of the same species

cooperate in caring for the young Reproductive division of labor --

sterile individuals work for the benefit of a few reproductive individuals

Overlap of generations -- offspring contribute to colony labor while their parents are still alive

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