Table 1. Relationship of Insects with other Arthropods
Characters
Onychophora
Crustacea
Arachnida
Chilopoda
Diplopoda
Insects (Hexapoda)
1.
Habit
Terrestrial
Aquatic and
few terrestrial
Terrestrial
Terrestrial
Terrestrial
Many
terrestrial and
very few aquatic
2.
Body
regions
Not distinct
Two-
Cephalothorax
and abdomen
Three-Pro,
meso and
Metasoma eg.
Scorpion Two-
Pro and
Opisthosoma
eg.
Spider
Two-Head and
multisegmented
trunk
Two-Head and
multisegmented
trunk
Three-Head, thorax
and abdomen
3.
Antenna
1 pair
2 pair -
Antennule and
Antenna
No
antenna
One pair
One pair
One pair
4.
Visual
organs
Not distinct
One pair-
Stalked
compound
eyes
One
pair-simple
eyes
One pair-simple
eyes
One pair-simple
eyes
Both simple eyes and
compound eyes (one
pair)
5.
Locamotor
organs
Many pairs of
unjointed legs
Minimum five
pairs of
biramous legs
Four
pairs
One pair per
segment (First
pair of legs
modified as
poison claws)
Two pair per
segment (No
poison claws)
Three
pairs of legs on
three thoracic
segments and two
pairs of wings on
meso and metathorax
Insect Morphology and Systematics
www.AgriMoon.Com
15
6.
Mouth
parts
Non
mandibulate
Mandibulate
(1 pair)
Non
mandibulate,
but possess
chelicerae
Mandibulate
- 1 pair
Mandibulate
- 1 pair
Mandibulate - 1 pair
7.
Respiration
Cutaneous
Gill breathing
Book lungs
(Scorpion) and
tracheal
(spiders)
Tracheal
Tracheal
Tracheal
8.
Body fluid
Haemolymph
Haemolymph
Haemolymph
Haemolymph
Haemolymph
Haemolymph
9.
Circulatory
system
Heart with
ostia
Heart with
ostia
Heart with ostia
Heart with ostia
Heart with ostia
Heart with ostia
10.
Developme
nt
Anamorphosis
Anamorphosis
Metamorphosis
absent-
Scorpion;
Metamorphosis
present-mites
Metamorphosis
Metamorphosis
Metamorphosis
11.
Habit
Feed on
organic matter
Herbivorus and
Carnivorous
Phytophagous
and predators
Carnivorous
Herbivorous
Phytophagous,
predators and
parasitoides
12.
Special
features
Link between
Annelida and
Arthropoda
Calsification
strengthens
exoskeleton
Life cycle; Egg-
larva-numph-
adult
larva with
3 paris of legs
Opisthogenital-
gonopore
present in the
terminal
Progogenital-
gonopore in 3rd
segment
Genital structures on
8th and 9th
abdominal segments.
Brain with
proto,
Insect Morphology and Systematics
www.AgriMoon.Com
16
and Nymph with
4
pairs of legs
segment
deuto
and
tritocerebrum
Insect Morphology and Systematics
www.AgriMoon.Com
17
ii. Lac gland - e.g. Lac insects
iii. Moulting gland secreting moulting fluid.
iv. Androconia or scent scale - e.g.moth
v. Poison gland - e.g. slug caterpillar
Functions of Body wall
i. Acts as
external armour
and strengthen external organs like jaws and ovipositor
ii. Protects the organs against physical aberation, injurious chemicals, parasites, predators and
pathogen.
iii. Internally protects the vital organs, foregut, hindgut and trachea.
iv. Provides space for muscle attachment and gives shape to the body.
v. Prevents water loss from the body.
vi. Cuticular sensory organs helps in sensing the environment.
vii. Cuticular pigments give colour.
Dostları ilə paylaş: