Insecta

Question 1

Insecta definition

4 points

Answer 1

1. Hexapod arthropods
2. external mouthparts and unbranched appendages
3. Three body parts:
   head,
   thorax,
   abdomen
4. Head has five sets of appendages
5. Thorax has three pairs of walking legs

Question 2

Insecta definition

Two wingless taxa

Answer 2

Archaeognatha,

Zygentoma

Question 3

Insecta definition

One winged or secondarily wingless taxa

Answer 3

Pterygota

Question 4

Insecta Body plan
Head
3 points

Answer 4

1. (6 segments)
2. Procephalon: antennae and eyes
3. Gnathocephalon: mouthparts – labrum, mandibles, maxillae, labium

Question 5

Insecta Body plan
Thorax
4 points

Answer 5

1. (3 segments)
2. Prothorax: legs
3. Mesothorax: legs, (wings)
4. Metathorax: legs, (wings)

Question 6

Insecta Body plan
Abdomen
4 points

Answer 6

1. 11 segments
2. May have rudimentary appendages called styli
3. Copulatory appendages (segments 8 and 9 in females, 9 and 10 in males)
4. May have terminal cerci

Question 7

Insecta Respiration

5 points

Answer 7

1. Entirely separate from circulatory system
2. Tracheal system throughout body

Tracheae run from valved spiracles to cells

Air sacs

4. Cuticular respiration
   Small, soft-bodied insects and larvae
5. Gills
   Aquatic insects and larvae
   Adapted from tracheal trunks

Question 8

Circulation

3 points

Answer 8

1. Transport of nutrients only
2. Body cavity is a haemocoel filled with haemolymph
   Pericardial sinus
   Perivisceral sinus
   Ventral sinus
3. Dorsal heart
   Chamber in each segment of the abdomen
   Non-contractile aorta in thorax

Question 9

Nervous system

3 points

Answer 9

1. Dorsal brain
   Protocerebrum: optic nerves
   Deuterocerebrum: antennal nerves
   Tritocerebrum
2. Suboesophageal ganglion
   Associated with the three segments that bear mouthparts
3. Ventral nerve trunks
   ganglia

Question 10

Digestion

3 points

Answer 10

1. Foregut (stomodaeum)
   Salivary glands
   Food storage
   Grinding denticles
2. Midgut (mesenteron)
   Peritrophic membrane
   Gastric caeca - absorption
3. Hindgut (proctodaeum)
   Absorption
   Water conservation

Question 11

Excretion

2 points

Answer 11

1. Malpighian tubules attach at junction of midgut and hindgut
   Blind ending
   May be present in very large numbers
   Muscle fibre helps them move
2. Nitrogenous waste collects inside, discharged into gut
   Primarily uric acid

Question 12

Reproduction

3 points

Answer 12

1. Mating stimulus induces female receptivity
   Odour signals
   Sound signals
   Colour signals
   Mating behaviour with or without tactile signals
2. Internal fertilisation
3. A female generally mates once or a few times in her life

Stores sperm

Question 13

Ecology

Answer 13

1. Most are herbivorous
   Important pollinators
   Important pests

Question 14

Fossil History

4 points

Answer 14

1. Earliest insects 480 Mya (Ordovician Period)
   About same time as terrestrial plants
2. Earliest winged insects 400 Mya (Devonian Period)
3. Major radiation in Carboniferous Period (356-299 Mya)
4. Most extant groups evolved during Permian Period (299-252 Mya)
   Permo-Triassic mass extinction

Question 15

Major divisions of the Insecta

3 points

Answer 15

1. Insect phylogeny is a mess
2. Many of the traditional names are paraphyletic
3. Uncertain status of fossil forms

Question 16

classification online

Answer 16

Phylum: arthropoda
Class: insecta

Question 17

Apterygota

3 points

Answer 17

1. Paraphyletic group
2. Never had wings
3. bristletails and silverfish

Question 18

Paleoptera

3 points

Answer 18

1. Paraphyletic group
2. Lack ability to fold wings
3. mayflies and dragonflies

Question 19

Neoptera

4 points

Answer 19

1. Winged insects that can flex wings over abdomen
2. Polyneoptera – grasshoppers, cockroaches (chewing mouthparts)
   Incomplete metamorphosis
3. Paraneoptera – true bugs, lice (sucking mouthparts)
   Incomplete metamorphosis
4. Holometabola – beetles, lacewings, bees, flies, moths
   Complete metamorphosis