Applied Entomology
Residential Pest Insects & Basic Concepts of Their Control
What is Entomology?
Entomology: the science that studies insects.
Insect groups include:
Phylum Arthropoda
Class Insecta/Hexapoda
Apterygota (Ametabola)
Pterygota (Exopterygota & Endopterygota)
Hemimetabola & Holometabola
Note!
1. Phylum Arthropoda
A group of animals with segmented bodies, jointed legs, and an external
skeleton (exoskeleton). Examples: insects, spiders, shrimp, centipedes.
2. Class Insecta/Hexapoda
Insecta = insects.
Applied Entomology 1
, Hexapoda means “six-legged” (hexa = 6, poda = legs). This group generally
has 3 pairs of legs.
3. Wingless vs. winged insects
a. Apterygota (Ametabola)
Apterygota = wingless insects (they never had wings throughout their
evolutionary history).
Ametabola = no true metamorphosis. The young resemble miniature
versions of the adult and only grow larger through molting.
A commonly cited example: silverfish (order Zygentoma).
b. Pterygota
Pterygota = winged insects (or descendants of winged ancestors).
1. Exopterygota
Wings develop externally during the juvenile (nymph) stage. There is
no pupal/cocoon stage.
Examples: grasshoppers (Orthoptera), cockroaches (Blattodea),
dragonflies (Odonata), true bugs/planthoppers (Hemiptera), praying
mantises (Mantodea).
2. Endopterygota
Wings develop internally during the larval stage, then appear during
the pupal/cocoon stage.
Examples: butterflies/moths (Lepidoptera), flies (Diptera), mosquitoes
(Diptera), beetles (Coleoptera), bees/wasps/ants (Hymenoptera).
4. Types of metamorphosis
a. Hemimetaboly (incomplete metamorphosis)
Sequence: egg → nymph → adult (imago).
Nymphs resemble adults, but are not sexually mature and their wings are
usually not fully developed. No pupa.
Examples: grasshoppers, cockroaches, dragonflies.
b. Holometaboly (complete metamorphosis)
Applied Entomology 2
Residential Pest Insects & Basic Concepts of Their Control
What is Entomology?
Entomology: the science that studies insects.
Insect groups include:
Phylum Arthropoda
Class Insecta/Hexapoda
Apterygota (Ametabola)
Pterygota (Exopterygota & Endopterygota)
Hemimetabola & Holometabola
Note!
1. Phylum Arthropoda
A group of animals with segmented bodies, jointed legs, and an external
skeleton (exoskeleton). Examples: insects, spiders, shrimp, centipedes.
2. Class Insecta/Hexapoda
Insecta = insects.
Applied Entomology 1
, Hexapoda means “six-legged” (hexa = 6, poda = legs). This group generally
has 3 pairs of legs.
3. Wingless vs. winged insects
a. Apterygota (Ametabola)
Apterygota = wingless insects (they never had wings throughout their
evolutionary history).
Ametabola = no true metamorphosis. The young resemble miniature
versions of the adult and only grow larger through molting.
A commonly cited example: silverfish (order Zygentoma).
b. Pterygota
Pterygota = winged insects (or descendants of winged ancestors).
1. Exopterygota
Wings develop externally during the juvenile (nymph) stage. There is
no pupal/cocoon stage.
Examples: grasshoppers (Orthoptera), cockroaches (Blattodea),
dragonflies (Odonata), true bugs/planthoppers (Hemiptera), praying
mantises (Mantodea).
2. Endopterygota
Wings develop internally during the larval stage, then appear during
the pupal/cocoon stage.
Examples: butterflies/moths (Lepidoptera), flies (Diptera), mosquitoes
(Diptera), beetles (Coleoptera), bees/wasps/ants (Hymenoptera).
4. Types of metamorphosis
a. Hemimetaboly (incomplete metamorphosis)
Sequence: egg → nymph → adult (imago).
Nymphs resemble adults, but are not sexually mature and their wings are
usually not fully developed. No pupa.
Examples: grasshoppers, cockroaches, dragonflies.
b. Holometaboly (complete metamorphosis)
Applied Entomology 2
