Module 2: Entomology

Entomology

Deals with arthropod pests and vectors of disease agents to livestock, poultry, pets and wildlife.

• Head

• Thorax

• Abdomen

Body is segmented into three regions

Chitin

Body is covered with?

Sclerite

The typical body segment is called?

• Tergum

• Sternum

• Pleuron

The sclerite is divided into:

Cuticle

The integument is composed of?

Cuticle

It serves as the exoskeleton of the insect

Cuticle

The site for muscle attachment and the first line of defense

Hemocoele

Space full of blood which bathes all body organs

Pericardium

It encloses the heart

Paired ostia

Openings in the pericardial walls

Gills (bronchiae)

Respiration found in larva, nymph, and adult aquatic species of various kinds

Trachea

Fine elastic tubes in the chitinous lining which branches and ramifies among tue internal organs

Lung book

Respiration found in spiders

Gill book

Respiration found in crabs

Spiracle

Smaller circular opening in the exoskeleton

Foregut or stomodeum

In digestion, involved in indigestion, passagec and disintegration of food particles

Midgut or mesenteron

In digestion, this is where storage of food and enzyme secretion

Hindgut or proctodeum

In digestion, this is where absorption of food and expulsion of fecal materials

Paired nephridia

Remove metabolic wastes crustaceans

Malpighian tubules

A type of excretory and osmoregulatory system found in some insects, myriapods, arachnids and tardigrades

Coxal gland

For collecting and excreting urine in arachnids and other chelicerates

Supraesophageal center

The brain

Indirect/ Complete metamorphosis/ Holometabolous life cycle

Characterized by having the 4 stages: egg, larva, pupa, adult. The hatched insect differs morphologicay from parent

Direct/ Incomplete metamorphosis/ Hemimetabolous life cycle

1 or 2 of the stages are missing with the exception of the adult

Egg

Stage that undergoes a series of segmentation

Larva

Developing form after it has emerged from the egg and before it is transformed into a pupa

Larva

The feeding stage of the parasite

Pupa

The quiescent stage of metamorphosis that emerge from the larval stage

Nymph

Form that leaves the egg with similarity in morphology with that of the adult

Adult

The reproductive stage of the parasite

Imago

The young adult

Polypod

• Larva with a marked head

• 3 segmented thorax with legs

• 10 segmented abdomen

• pair of abdominal legs or fleshy hooked legs

Oligopod

• Larva with a well-marked head

• 3 pairs of thoracic legs

• No abdominal legs

Apodous

Larva with no legs on the thorax and abdomen

Free or exarate

In pupa, the winsg and legs and free from the body and can be seen externally

Obtectate

In pupa, the legs and wings are bound to the body by molting fluid but still visible externally

Coarctate

In pupa, last larval skin retained; this hardened skin encloses the pupa hence it cannot be seen externally

Puparium

Hardened skin

Oviparous

A type of female that lay undeveloped eggs (housefly, stablefly)

Ovoviviparous

Type of female that lays larvated egg

Viviparous/ larviparous

Type of female that lays fully-developed larva (fleshflies, tsetse flies, Oestrus ovis)

Pupiparous

Type of female that lays larva that immediately turns into pupa (pigeon louse fly)

Parthenogenetic

Type of female that reproduce without males/fertilization (silkworm, Strongyloides sp.)

Crustacea

This class of arthropods:

Main body divisions are cephalothorax and abdomen; legs are found on thoracic and abdominal segments

Arachnida

This class of arthropods:

Adult with 4 pairs of legs; 2 pairs of mouthparts without antennae and wings

Pentastomida

This class of arthropods:

Adult without legs except 2 pairs of hooks near the mouth, larvae with 2 leg pairs

Insecta

This class of arthropods:

Adults with 3 pairs of legs; body divided into 3 main parts: head, thorax, and abdomen

Diplopoda

Under myriapoda,

elongated, cylindrical, terrestrial with numerous segments, each bearing 2 pairs of legs, with a pair of antennae

Chilopoda

Under myriapoda,

long, narrow, and dorso-ventrally flattened; body with several segments each bearing a pair of jointed legs