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SOCIAL INSECTS. MRS FARKHUNDA NAZ LECTURER ZOOLOGY DADC. CONENTS OF PRESENTATION. 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
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SOCIAL INSECTS MRS FARKHUNDA NAZ LECTURER ZOOLOGY DADC
CONENTS OF PRESENTATION • 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
CONTENTS OF PRESENTATION • 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
CHARATERISTICS OF CLASS INSECTA -**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
The Praying MantisClass InsectaPhylum ArthropodaKingdom Animalia
A Class of Distinction • 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.
NUMBER OF SPECIES • 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.
Number of individuals • 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.
Distribution • The petroleum fly (Helaeomyia petrolei), develops in pools of crude oil in the California oil fields. A related species, the brine fly (Ephydra cinera), thrives in the high salinity of Utah's Great Salt Lake. • In fact, the only place on earth where insects are not plentiful is in the ocean depths. Most marine environments are filled by another successful group of arthropods, the Crustacea.
Reasons for Success Exoskeleton • 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
Small Size • 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.
Flight • 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 Potential • 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).
Metamorphosis • 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.
Adaptability • 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.
LOCOMOTION • 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.
IMPACT OF INSECTS • 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.
INSECT AS FOOD • 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.
ECOLOGICAL IMPACT • 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.
PRODUCTS OF BENEFICIAL INSECTS • Honey & Beeswax • Silk • Shellac • Cochineal • Tannic acid
Diptera (two wings) Having two membranous, somewhat transparent wings.Feeding strategy- nectarivory, herbivory, carnivory and omnivory. • Phylum Arthropoda • Subphylum Uniramia • Class Insecta • Order Diptera • common Fly
Hemiptera (part wing) Their wings have hard proximal parts and distal membranous tips. They possess a stylet for sucking juices of plants or animal blood.Trophic strategy- Herbivory • Phylum Arthropoda • Subphylum Uniramia • Class Insecta • Order Hemiptera • common True bug
Hymenoptera (membrane wings). They possess four membranous (somewhat transparent) wings.Pollinators, Nectarivory, hervivory and carnivory. • Phlyum Arthropoda • Subphylum Uniramia • Class Insecta • Order Hymenoptera • Common – bees, wasps, and ants
Lepidoptera ( scale wings ) possess 4 wings covered with minute scales. The larvae are herbivores and adults are nectarivores. • Phylum Arthropoda • Subphylum Uriramia • Class Insecta • Order Lepidoptera • common – Moths and butterflies
Orthoptera (straight wings)The wings are held roof like over the abdomen. Hind legs are adapted for jumping • Phylum Arthropoda • Subphylum Uniramia • Class Insecta • Order Orthoptera • Common- Grasshoppers, crickets, walking sticks, praying mantis, cockroaches.
SOCIAL INSECTS • 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.
EUSOCIAL INSECTS • 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
EUSOCIAL ORDERS • Relatively few insects are classified as eusocial -- the distinction is limited to the following groups: • Order Isoptera Order Hymenoptera • Termites -- all Ants -- all species speciesBees -- about 600 Wasps -- about 700
Types of ants • With more than 8,800 described species, ants are the most ecologically diverse of all social insects. The following list includes some of the more common groups. • Army ants Fire ants • Harvester ants Thief ants • Slave-maker ants. Honey-pot ants • Leafcutter ants • Weaver ants
Types of social wasps • There are about 20 species of social wasps in North America and more than 700 species world-wide. They can be divided into three groups: • Yellowjackets. • Hornets. • Common paper wasps.
forensic entomology • When investigators arrive at the scene of a crime, they rely on a number of procedures to allow them to determine what has transpired. A technique which is gaining in popularity as it is refined is that of forensic entomology, or the use of insects in crime scene investigations.
Forensic Entomologist • By knowing the conditions which a carcass (or human corpse) has been exposed to, and by carefully comparing the stages of development and species of fly present to tables of developmental rates, a Forensic Entomologist may gain a rough estimate of the time a corpse has lain out in the elements, and even whether it has been moved.
REFERNCES • www.googlesearch.com • www.wikipedia.com
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