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ENTOMOLOGI

Adi BasukriadiDepartemen Biologi FMIPA UI

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Entomology as a Science

Entomologyis a division of biology (study of life),specifically zoology (study of animals) that focuses onthe study of insects

Other arthropods often get thrown into the disciplinesuch as spiders, mites and ticks

What is economic entomology?

the area of entomology that deals with insects

and related arthropods that have an economicimpact on man (+ or - )

most insects are of little consequence to manalthough important ecologically eg. Cockroaches

and butterflies

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Introduction

Why study insects ?

The insects comprise a large group of organisms that areimportant academically, ecologically, economically, and

medically.

Significance of insects

Academic importance

Importance in natural communities (ecological)

Importance from human perspective (economic, medical)

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1. Academic importance

1. They are the largest group of organisms on the planet. Manyestimates are around 850,000 species. Many authorities agree thatthe actual number will be 1,000,000 to 10,000,000. Other estimates(Terry Erwin, Smithsonian) range up to 18,000,000 species.

2. They occur in extremely large numbers of individuals. It has beenestimated that there are 400 pounds of insects per acre in the US (ascompared to 14 pounds of humanity/acre)

3. They are found in all habitats on Earth (except oceans). They arevery successful terrestrially (on land) and in fresh water.

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2. Importance in natural communities (ecological)

1. They are important pollinators of flowering plants.

2. They are predators of other insects and many other invertebrate

organisms.3. They are parasites of many organisms.

4. They are scavengers and detritivores, working in conjunction withfungi and bacteria to decompose plants, animals, and droppings.

5. They serve as food for birds, fish, and other animals.6. They aerate the soil and add organic matter to it.

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3. Importance from the human perspectiveThese issues are mainly economic and medical

1. If the insects are pollinating crops and orchards, they are considered"good." They are also considered "good" if they eat or parasitize"bad" insects.

2. They are considered "bad," if in their lives, they ...

destroy agricultural crops, fruits, shade trees, ornamentals, turf,stored products, and household items (such as clothing) [billionsof $$ per year]

vector diseases of humans and domestic animals, includingyellow fever, malaria, typhus, plague, African sleeping sickness,encephalitis, tularemia, Chagas' disease, Texas cattle fever, andserve as intermediate hosts for certain tapeworms.

act as causative agents themselves as bot flies, screwworms, oras nuisance agents such as flies, mosquitoes, and wasps.

We make special distinctions when insects, in living out their lives, impact

on human lives. We then make value judgments as to "goodness" or

"badness."

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Insect Success

Insects have been around for over 350 million years(humans only about 2 million yrs)

Insects out-number people 2 million to 1.

Estimated to be apprx. 40 million insects/acre

What about mass?

Estimated in the US there are 400lbs of insect/ac

Compared to 14 lbs flesh and bone (vertebrates)

In Amazon, ants alone outweigh vertebrates 4-1Intelligence is a necessary component of evolutionary

success?

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Insect Diversity

Insects can be found everywhere on earth except polarice caps and ocean depths

How many species?

Over 900,000 describedEstimated there many be from 2 10 million total

In the Amazon, its estimated that 90% are yet to be

described

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Numbers of arthropod species compared to all sp.

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Biodiversity

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What is an Insect ?

An insect is a member of the Phylum Arthropoda, Subphylum Uniramia,Class Hexapoda. This class, like the phylum, is a highly diversecollection of arthropods which possess a common set of characteristics.

General characteristics of arthropods applicable to insects

paired, segmented appendages

regionalized body exoskeleton

trachea

centralization of nervous system

metamorphosis

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three body regions

head

thorax abdomen

specific mouthparts including: mandibles

maxillae

labium

one pair ofantennae

compound eyes and ocelli typically present

thorax with three pairs oflegs

(one pair per thoracic segment)

abdomenof eleven segments

(not all may be visible)

Malpighian tubules present

(function in water conservation)

trachea (function in respiration)

many with two pairs ofwings (sometimes one pair or none)

metamorphosis common : simple, complete, other types

Specific characteristics of insects

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Types of Entomologists

Taxonomists/ systematists study ID and classificationof insects

Economic Entomologists focus on the management ofeconomically important species

Includes insecticides, biological control, culturalpractices, monitoring and sampling etc

This may be in any system agricultural, urban,forest, aquatic etc.

Medical Entomologistsstudy medically importantspecies

Apiarist - beekeepers

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Apitherapy

One of the major peptides in beevenom, called Melittin, is used totreat inflammation in sufferers ofRheumatoid Arthritis and MultipleSclerosis.

Melittin blocks the expressionof inflammatory genes, thusreducing swelling and pain.

It is administered by directinsect sting, or intramuscularinjections.

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Types of Entomologists(contd)

Just about any discipline you can think of using insectsas a system

Insect ecologists

Insect physiologistsInsect behavioralists

Insect Neurology

Insect Geneticist (fruit fly Drosophila malanogasterfirst animal to have genome sequenced)

Etc.

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Insect Genetics

The model organism, Drosophilamelanogaster

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Users of Entomology Information

Farmers

General Public (homeowners etc)

Medical Doctors

Veterinarians

Police (forensic entomology)

Various industries (stored products pests)

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Forensic entomologyis the application of the study of insects andother arthropods to legal issues, especially in a court of law.

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Insect Success

Insects have been around for over 350 million years(humans only about 2 million yrs)

Insects out-number people 2 million to 1.

Estimated to be apprx. 40 million insects/acre

What about mass?

In Amazon, ants alone outweigh vertebrates 4-1

Intelligence is a necessary component of evolutionary

success?

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Reasons for Insect Success:

Body architecture

The exoskeleton is light and strong protects tissuesExoskeleton is more efficient for attachment of muscles

Waxy coating prevents water loss very important for smallanimals on land

Jointed appendages were able to adapt for locomotion, feeding(including mouthparts), reproduction etc.

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Reasons for Insect Success(contd):

Small Size

Allows use ofsmallresources

Increasesability to hide /escape frompredators

Facilitatesdispersal (candisperse bywind)

Goliath beetle

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Reasons for Insect Success(contd):

Ability to fly

Allows escape from predation and unfavorableconditions (drought etc)

Allows widespread dispersal can colonize newhabitat

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Reasons for Insect Success(contd):

Reproductive capacity

Ability toproduce large numbers of eggs in a shortperiod of time creates lots of genetic variabilityallows insects to adapt quickly to newenvironments

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Reasons for Insect Success(contd):

Insects can adapt to even the harshest living conditions.

The young of some insects live in pools of crude oil. Some live in streamswhere the temperature falls to 0 Co. Others live in hot springs where thetemperature rises to 49 Co.

Although most insects feed on plant life, many have adapted themselvesto eating almost anything. Various kinds of insects eat fabrics, opium,

mustard plaster, cork, tobacco, face powder, paste, or pepper.

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Benefits of Insects:

As a primary resource (something they produce directly)

Insects serve as food in many cultures

Produce silk (from salivary glands of silk moth

Bombyx mori

2,000 billion moths per year)Produce honey and wax (honey beeApis mellifera)

Lac scales are used in making shellac

A number of scales are used in making dyes

Used as experimental subjects

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Benefits of Insects(contd):

As an intermediate resource (interact with environmentto give a benefit)

Very important in pollination (most fruit andvegetable crops)

As agents of biological control to eat or parasitizepest insects

As scavengers to feed on dead plant and animal

material (nutrient cycling)As a food resource for other wildlife

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Negative Impacts of Insects:

Injure crops, forests and ornamentals

Damage may be direct where they feed on the partof crop we use. Eg codling moth on apples, or aremerely present eg CA red scales on citrus

OrIndirect where they feed on parts of the plantwe dont use eg root feeders, leaf feeders reduces quality or potential yield

May also act as vectors of plant diseases egPierces disease

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Negative Impacts of Insects(contd):

Annoyance, injury and death to humans and animals

Insects like mosquitoes, lice, fleas etc annoy anddiscomfort

Venomous insects can even cause deathInsects ticks and mites can vector disease eg

malaria, yellow fever, encephalitis, Lyme disease

Numerous insects are parasites of domesticated

animals eg. Stable fly, horn fly, screwworm

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Negative Impacts of Insects(contd):

Destruction or damage to stored products or possessions

Insects feed on stored grains and processed foods

Feed on household possessions eg clothes moths

and carpet beetlesTermites cause serious damage to homes