introduction to insect world
DESCRIPTION
you can find answers to what are insects, evolution, why are they dominant creatures on earth, population size, where they are found, life cycle, how insects see, etc.,TRANSCRIPT
An Introduction to
Insect World (Amazing facts about insects)
RASHMI, M.A Research Scholar
What are insects? For most of us…..
any small creature crawling /creeping is an insect….
All these are not insects!!
Scorpion Centipede
Earthworm Mites Millipede
Spider
Then what are insects??
Great Diversity
Insects Most dominant of all creatures on
earth
Highly abundant in all ecosystems
What is the population size of insects on earth?
? ?
Where do you find them?
Artic to Antarctica
….found Everywhere
Sea level to 6000m above
sea level
Most arid desert to Evergreen
forests
Hot sulphur spring (55 0) to
cold polar habits(-2 0 )
What are the Reasons for Insect Dominance?
Antiquity
Earth 6 billion years ago
3.2 billion years oldest unicellular fossils
600 million years BP Protoarthropods
575 million years BP Cambrian explosion
Collembolans & thysanurans Oldest hexapodan fossils
420 million years BP 150 -175 million years Flowering plants
8-4 million years Bp Great ape’s
200,000 years ago Modern humans
Longest insect -555mm Pharnacia serratipes
Female stick insect from west Malaysia
Minute parasitic -Mymar species-0.2mm
Insects demonstrate a great range in their body sizes
However, due to their enormous variation in form it is difficult to
make comparisons
Great range in their body sizes
The long horned beetle, Titanus giganteus
Measuring 15 to 20cm in length
Dynastes hercules
measuring15 to 18cm &
weigh up to 88grams.
The largest Indian beetle, Chalcosoma atlas measuring
Up to 7.5cm
Heaviest weighing beetle, Goliathus goliathus
weighing up to 100grams
Western pigmy blue from USA
is the smallest butterfly
measures about 1.5cm across the wings
Queen Alexandra Birdwing
(Ornithoptera alexandrae)
is the largest butterfly in the world,
wing span up to 30cm.
Atlas Moth (Attacus atlas)
Found only in Southeast Asia,
the Atlas Moth is the largest of the moth species with the largest
wing surface area—close to sixty five square inches
& a wingspan of up to a foot long.
Presence of Functional Wings
Birds, Bats- 1 pair of wings (modified fore limbs) Insects- true wings evolved independent of any limbs Wings of Insects have developed over a period of 300 million yrs against
pterosaurs 225 m years Birds 125 m years Bats 50 m years
Flight provides: Means of escape – Weather Food Enemies
Migration in Monarch Butterfly
Can Man Race with Insects??
Mosquito 20miles (32Km)per Hour
Honeybee
13miles
(22Km)per Hour
Sphinx moth 33miles (53Km) per Hour
Dragonfly 61miles (98Km) per Hour
Horsefly 91miles (146Km) per Hour
Human 6.2miles (10Km) per Hour
1 2
3
4
5
6
Life cycle of Insects
Insects undergo metamorphosis for their growth and development Metamorphosis in insects is the biological process of development. There are two forms of metamorphosis: Incomplete metamorphosis and Complete metamorphosis
Metamorphosis
Incomplete Metamorphosis
Nymph
Egg Adult
Here u can see how a Dragon fly molting its exoskeleton Nymph to adult formation
Nymph
Adult
Egg Larvae
Pupae
Adult
Complete Metamorphosis
Phenological adjustments- facilitating the timing of occurrence of their different stages
7.Mayflies 24 HOURS! 6.Drone Ants 2 Weeks 5. Bees 4/5 Weeks
4. Dragon flies 4 Months 3. Cicadas 17 years
2. Queen
Ant 25
years
1.Termite Queen - 50
years
What is the life span of insects??
Diversity of food habits
Insects exhibit a great diversity of food habits
they eat virtually everything that is organic by origin
Fungivory Necrophagy Nectarivores & pollen feeders Phytophagous
Carnivory
Coprophagy
Detritivory Powder post beetle
Decentralized nervous system
Exoskeleton
Enormous Reproductive Ability
Specialized offence and defense mechanisms
Camouflage
Lichen moth
Dying leaf katydid
Dead leaf butterfly
Camo Moth Flower mantid
Insects have mosaic vision
How insects see?
Compound eye with no. of Ommatidia
Components of Ommatidia
Compound eyes, contains from 6 to 28,000 or more light-sensitive structures, called Ommatidia, grouped under a lens or cornea that is composed of an equal number of hexagonal prism-shaped facets.
Ult
ravi
ole
t
Red
Visible spectral range of human and bee
Glow worm emitting light
Lampyridae is a family of insects in the beetle order Coleoptera. They are winged beetles, and commonly called fireflies or lightning bugs for their conspicuous crepuscular use of bioluminescence to attract mates or prey
Light production for communication
Synchronous flashing of lights by Firefly larvae in forest
lanterns (part of their abdomens)
Magnesium ions & ATP
Communication by chemicals
Male having special organ for
sensing the signal
Female producing Signal
through chemicals
This system is very specialized & sophisticated
This system is used in finding food,
mates, marking territories, defense,
marking food etc.
What is the importance of insects to man?
Ecosystem functions
Pollination Energy transfer Nutrient cycling Scavenging Earth moving
Pests
Live stock Crops Transmit diseases
A dung beetle hard at work
Scavenging
Pollination
Fig wasp
Predators & Parasitoids
Ground Beetle Attacking
Caterpillar
Adult parasitizing on
Helicoverpa egg
Parasitoids
Tricogramma sp
Cryptolaemus montrozeri
Predatory coccinellids
Green lace wing
Larvae feeding on aphid
Stalked eggs
Adult
Weed killers
Zygogramma bicolorata
Parthenium weed Opuntia- Cactoblastis cactorum
Medicinal uses The venom of honey bees is used to ameliorate inflammatory and
autoimmune conditions such as multiple sclerosis, arthritis, rheumatism, Maggots have been used to treat abscesses, burns, cellulitis,
gangrene, ulcers.
Model organism- Genetic studies & Evolutionary theories
Gene expression Genetic recombination Genetic inheritance
Food Products
Insects are an extremely rich source of high quality proteins, fats, essential vitamins, and minerals.
Honey, Human food, Pet food, Livestock feed
Royal jelly Fine fabrics-Silk
Extends the life span Treating some bone, joint disorders & rheumatoid arthrit .
Secretions and Dyes
Beeswax
polishing woods, making candles, packaging, processing, preserving foods, cigarette filters & waterproofing material
the basic ingredient of a vast list of products, including stiffening agents in the toes and soles of shoes and felt hats, shoe polishes, artificial fruits, lithographic ink, glazes in confections, phonographic records, playing card finishes, and hair dyes.
Shellac Lac insect
Inks
Iron gall ink Oaks produce Aleppo galls in response to a chemical substance secreted by larvae of the cynipid wasp, Cynips gallae-tinctoriae
Dactylopius coccus, used in the preparation of red dye The insects’ bodies contain the pigment called carminic acid
Carmine is considered safe enough for use in eye cosmetics
A significant proportion of the insoluble carmine pigment produced is used in the cosmetics industry for hair- and skin-care products, lipsticks, face powders, rouges, and blushes
A bright red dye and the stain carmine used in microbiology
The pharmaceutical industry uses cochineal dye to color pills and ointments
Dactylopius coccus
Medical Entomology
Insect are vectors of human diseases
Vector of Malaria
SN: Anopheles quadrimaculatus
Dengue transmitting Mosquito
1.Mosquitoes – Malaria, yellow fever & dengue, filariasis,
encephalitis. Mosquitoes are responsible causing the most human deaths
worldwide than any other animal-almost two million annually
2. House flies – Dysentery, typhoid, cholera
3. Tsetse flies – African sleeping sickness
4. Horse flies & deer flies – Anthrax
House flies horse flies Tsetse fly
Forensic entomology
Is the application and study of insect and other arthropod biology to
criminal matters
In murder investigations it deals with which insects eggs when and
where, and in what order they appear in dead bodies
Insects exhibit a degree of endemism & well-defined phenology
Flies, beetles, mites, moths, wasps, ants &bees.
Flesh fly
blowfly
Rove beetles
Hister beetle
Carrion beetle
Clothes moth
Stenocara beetles live in the Namib Desert (southwest coast of Africa), one of the driest places on Earth (0.4 inches of rain annually) and this beetle has developed a unique technique to survive by obtaining water from early morning fogs.
Beetle inspired water harvester
Insects have served as excellent models for artisans, architects, engineers, craftsmen
& designers
The only monument in the world built to honor an
Agricultural Pest
Boll Weevil Monument
Boll Weevil
Top ten reasons to study entomology
10. The Nobel Prize in Physiology and Medicine has been
awarded to biologists studying insects. How will you know which insect to work on
for your Nobel Prize unless you study insects?
9. Over half of the 2 million species described in the world are insects,
thus there is a certain generality that pertains to all studies of insects.
If you’re interested in biodiversity or ecology you need to study insects.
8. Many physiological processes, such as nutrient specific hunger, are similar in
insects and other animals, but are easier to study in insects.
7. Many serious diseases across the world have insect vectors.
You’ll need to learn insect biology if you want to cure a disease.
6. More species of insect have their genome sequenced than any
other type of multicellular organism. To study the blueprint for life,
insects are a great place to start.
5. Insects have been around for 370 million years and have evolved
solutions to many problems that still confound engineers.
The new field of biomimetic design builds on the
functional morphology of insects.
4. Insects live on all continents. Small flies even live year
round on Antarctica. You can travel the world and work
with insects where ever you go.
3. Students studying insects get in to top graduate schools
or get great jobs
2. Insects affect billions of $$ in agriculture for good as
pollinators and bad as herbivores. Study such insects and you can help society.
1. And the top reason to study insects is:
Insects are just too cool !
Acknowledgements Dept of Entomology, UAS, GKVK.