200,000 years ago
Modern humans 8-4 million years Bp
150 -175 million years
420 million years BP
Collembolans & thysanurans
Oldest hexapodan fossils
575 million years BP
600 million years BP
3.2 billion years oldest
6 billion years ago
Great range in their body sizes
Insects demonstrate a great range in their body sizes
However, due to their enormous variation in form it is difficult to
Minute parasitic -Mymar species-0.2mm
Longest insect -555mm Pharnacia serratipes
Female stick insect from west Malaysia
The long horned beetle, Titanus giganteus
Measuring 15 to 20cm in length
Heaviest weighing beetle, Goliathus goliathus
weighing up to 100grams
The largest Indian beetle, Chalcosoma atlas measuring
Up to 7.5cm
measuring15 to 18cm &
weigh up to 88grams.
Queen Alexandra Birdwing
is the largest butterfly in the world,
wing span up to 30cm.
Western pigmy blue from USA
is the smallest butterfly
measures about 1.5cm across the wings
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
Migration in Monarch Butterfly
Can Man Race with Insects??
20miles (32Km)per Hour
Life cycle of Insects
Insects undergo metamorphosis for their growth and
Metamorphosis in insects is the biological process of
There are two forms of metamorphosis:
Incomplete metamorphosis and
Phenological adjustments- facilitating the timing of occurrence of their different stages
What is the life span of insects??
1.Termite Queen - 50
5. Bees 4/5 Weeks
3. Cicadas 17 years
6.Drone Ants 2 Weeks
4. Dragon flies 4 Months
7.Mayflies 24 HOURS!
Diversity of food habits
Insects exhibit a great diversity of food habits
Nectarivores & pollen feeders
Powder post beetle
they eat virtually everything that is
organic by origin
Enormous Reproductive Ability
Decentralized nervous system
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.
Compound eye with no. of Ommatidia
Components of Ommatidia
Visible spectral range of human and bee
Light production for communication
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
Synchronous flashing of lights by
Firefly larvae in forest
Magnesium ions & ATP
lanterns (part of their abdomens)
Communication by chemicals
This system is used in finding food,
mates, marking territories, defense,
marking food etc.
Female producing Signal
This system is very specialized & sophisticated
Male having special organ for
sensing the signal
What is the importance of insects to man?
A dung beetle hard at work
Predators & Parasitoids
Green lace wing
Adult parasitizing on
Larvae feeding on aphid
Ground Beetle Attacking
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,
Model organism- Genetic studies & Evolutionary theories
Insects are an extremely rich source of high quality proteins, fats, essential
vitamins, and minerals.
Honey, Human food, Pet food, Livestock feed
Secretions and Dyes
Extends the life span
Treating some bone, joint disorders &
rheumatoid arthrit .
polishing woods, making candles,
packaging, processing, preserving
foods, cigarette filters & waterproofing
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.
Iron gall ink
Oaks produce Aleppo galls in
response to a chemical
substance secreted by
larvae of the cynipid wasp,
Dactylopius coccus, used in the preparation of red dye
The insects’ bodies contain the pigment called carminic
Carmine is considered safe enough for use in eye
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
A bright red dye and the stain carmine used in
The pharmaceutical industry uses cochineal dye to color
pills and ointments
Insect are vectors of human diseases
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
Dengue transmitting Mosquito
2. House flies – Dysentery, typhoid, cholera
3. Tsetse flies – African sleeping sickness
4. Horse flies & deer flies – Anthrax
Vector of Malaria
SN: Anopheles quadrimaculatus
Is the application and study of insect and other arthropod biology to
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.
Insects have served as excellent models for artisans,
architects, engineers, craftsmen
Beetle inspired water harvester
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.
The only monument in the world built to honor an
Boll Weevil Monument
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 are just too cool !
Dept of Entomology, UAS, GKVK.