Ent 201 1st lecture.p agricultural pests

basic course to learn about insects

1. ENT. 201
Fundamentals of Entomology
LECTURE – 1
DEFINITION OF ENTOMOLOGY AND
INSECT; BODY REGIONS; BODY
SEGMENTATION; SURFACE AREAS OF
INSECT BODY

2. ENTOMOLOGY AND
INSECT
Entomology – two Greek words
entomon – equivalent to insectum (Latin) or insects (English) and
logos- discourse/study
Insect- derived from Greek word. Meaning : deep cut
Small in size
Entomology is the science which deals with study
of insects
Insects belong to the Phylum Arthropoda (Artho=
jointed, Poda= Legs) which is the biggest phylum of
kingdom Animalia
More than three quarters of the animals on earth are
arthropods, and most of these are insects

3. Branches of Entomology
insectsin
crime
useof
is known asForensic
1.Study and

investigations
Entomology
2.Studyofinsectsrelatedtolivestockand
veterinaryanimalsisknownas
Veterinary Entomology
3.Study of insects in relation to Human beings
is known as Medical Entomology

4. PHYLUM -
ARTHROPODAHave metameric segmentation;
more or less perfect bilateral symmetry and
elongated body with mouth and anus at
opposite ends
Have an external skeleton which is hardened
with lime and sclerotinous material
The most important anatomical feature is that
each body segment generally has a pair of
jointed legs, hence the name of the Phylum
Arthropoda

5. POSITION OF INSECTS IN ANIMAL KINGDOM
CLASS
ANIMALIA
ARTHROPODA
UNIRAMIA
KINGDOM
PHYLUM
SUBPHYLUM INSECT
A

6. MAJOR CLASSES OF PHYLUM ARTHROPODA AND THEIR CHARACTERSTICS
Class Examples(s) Body RegionsPair of
Legs
Pair of
Antennae
Breathing
Organs
Eyes Econ Imp.
CrustaceaCrayfish/ Prawn/
Crabs
Cephalothorax
& abdomen
5 or > 5 2 Gills Compound Minor pests
of
greenhouse
Arachnida Spiders/Ticks/
Mites/Scorpions
Cephalothorax
& abdomen
4 None Book lungs
& trachea
Simple Agriculture
&
veterinary
importance
Diplopoda Millipedes Head & Body
(rounded)
30 or >
30 (2
P/seg.)
1 Trachea Simple Pets of
tuber &
root crops
Symphylla Symphylans Head & Body
(flat)
12 1 and
long
Trachea None Garden
Symphylans
Chilopoda Centipedes Head & Body
(flat)
15 or >
15
1 and
very long
Trachea Simple Feed on
insects
Insecta Grasshoppers
/Bugs/Beetles/
Butterflies
Head, Thorax
& Abdomen
3 1 TracheaCompound
& simple
Great econ.
Imp. as are
major pests
of agric
crops

7. DIFFERENCES AMONG MITES, SPIDERS AND INSECTS
Characters Mites Spiders Insects
Antennae Absent Absent Present
Wings Absent Absent Present/
absent
Legs(adults) 4 pairs 4 pairs 3 pairs
Body
segmentation
Fused Fused Not fused
Body divisionGnathosoma &
Idiosoma
Cephalothorax
& abdomen
Head,Thorax &
abdomen
Feeding habitsDiverse Carnivorous Diverse

9. and they include beetles, dragonflies,flies,butterflies,honeybees,ants...
They are the most diverse group of animals on the Earth, with over a million described species.
Insects are a groupofarthropods like the rest of arthropods, they have an EXOSKELETON
(outside skeleton)
We have our skeleton inside of our
body (endoskeleton),butinsects
have theirs on the outside. This
format for body support is called
an exoskeleton and has been very
successfulforthem,buttheir
"skeleton" cannot grow. Insects
shed their skeletons several times
in their lifetime, when they have
grown too big for their "skins".

10. The body is organized into three regions or segments:
a HEAD, a THORAX, and an ABDOMEN
The insect body consists
of three parts : head,
thorax and abdomen

11. DEFINITION OF INSECT
An insect is a tracheate arthropod in which the body is
typically divided into three parts, namely head, thorax and
abdomen; it possesses one pair of compound eyes, one pair
of antennae, usually two pair of wings and three pairs of
legs and it has the reproductive aperture placed at the end
of the abdomen

12. Tagmosis : the differentiation of the body into distinct
functional regions or tagmata is called tagmosis.

13. Cranium : cranium is the hardened capsule of the head that bears
the mouth parts, antennae and eyes
Tentorium : it is the endoskeleton of the insect haed found from
invagiation of the body wall that provides rigidity and areas for
muscle attachment

14. The ventral side of the insect reveals a complicated set of feeding
mouthparts,
and distinct segmentation.