Lecture 1: Morphological Features Flashcards
What is an insect?
An arthropod with 6 appendages
Describe the morphology of the Class Insecta
- External Skeleton
- 6 legs
-Divided into head thorax and abdomen
Predominately:
Head
-feeding and sensory
Thorax (3 segments primitively)
-locomotion- if wings present, reside here
Abdomen (11 segments primitively)
-visceral function (maintenance systems)
The evolutionary trend of the abdomen is to reduce in segments
Paired antennae
- if wings present, reside here
Describe the segmentation of the arthropod head
Frons- front of the face Vertex- "head top" Gena- "cheeks" Clypeus- fold under the frons Ocelii Mouth parts
What is the function of the tendorium and how does it function
Strengthens the head capsule
Provides surface for muscle attachment
Mouth parts
(anterior) Upper lip- labrum, attached to clypeus
(posterior) Lower lip- labrium
In between lips:
Mandibles- paired
Maxillae- paired
Hypopharynx- “tongue”
Give the three types of head shapes and the reason for their name
Hypognathous head- Eg cockroach, downward pointing mouth part
Prognathous- Eg termites, forward extending mouthparts, associated with carnivorous insects
Opisthognathous- Eg Homoptera, backwards pointing mouth partss, proboscis slides between legs
What is a suture and give some named examples
Clypeo-labral
Clypeo- frontal
Epicranial
Name and define the parts of the antennae
Scape
Pedicel
Flagellum
What are the parts of the thorax and the structures they bare
Prothorax -front legs Mesothorax - front wing Metathorax - hind wing -hind legs
Give the parts of the insect legs
Coxa- usually short Tranchanter Femur Tibia Tarsi (tarsus)- with tarsal claw---- Grasping the substrate
Give the parts of the insect legs
Coxa- usually short Tranchanter Femur Tibia Tarsi (tarsus)- with tarsal claw> Grasping the substrate
What is a sclerite
A hard plate which forms part of the insect exoskeleton
What is a suture?
A junction between two sclerites
What is a conjuctiva?
A membranous structure which may join two sclerites
What is the apodeme
An invagination of the exoskeleton
What are palps
Jointed attachments of mouthparts which may be sensory, assist in manipulation of food or used for piercing into a food substrate
Give the type of head associated with downward pointing mouth parts
Hypognathous head
Eg Grasshopper
Describe an opisthognathous head
backward mouthparts
Eg Homoptera and Hemiptera
Describe a prognathous head
forward mouthparts
Eg Termite soldiers
Give the regions of the insect thorax
Notum- dorsal
Sternum- ventral
Pleuron- lateral
Explain the formation of insect wings
They form as extensions of the insect body wall filled with haemolymph. This happens when the epithelium secretes substances forming a cuticle, this cuticle further elongates and when the dorsal and ventral surfaces join together it forms the wing. This is why the wing has blood sinuses, trachea and nerves.
During the embryonic stages, the wing is composed of all components of the body wall including the epidermal cells, when these cells die, we are left with the exoskeletal component otherwise known as the wing
List the three main angles of viewing the insect wing
Humeral, anal and apex
List the three main margins of the insect wing
Costal anal and apical
Give the four types of cells of the wing and their description
Open- Open to the apical margin
Closed- Closed to the apical margin
Distal- Further from the costal margin
Basal- Close to the costal margin
