External Insect Morphology Flashcards
What are characteristics of arthropods? (8)
Segmented bodies
Paired appendages
Segmented appendages
Bilateral symmetry
Exoskeleton
Dorsal heart
Open circulatory system
Ventral nerve cord
What is metamerism?
a state of division of insect body into primary body segments
What is a metamere?
A primary body segments
How many metameres does the head have?
1-5
How many metameres does the thorax have?
6-8 metameres
How many metameres does the abdomen have?
9-20
What is tagmosis?
an evolutionary phenomenon of grouping body segments into functional units
What is a tagma?
a grouped segment of a functional unit
What are four advantages of the exoskeleton?
Acts as protective armor
Protects from invasion by pathogens and harmful agents
Impermeable to water
Acts as a base for muscle attachment
What is a disadvantage of the exoskeleton, and what must be done to overcome it?
Does not expand
Must be shed in order to grow- molting
What are the layers of the exoskeleton cuticle? (4)
Epicuticle
Exocuticle
Endocuticle
Epidermis
What is the epicuticle?
Non-living outermost layer
What makes up the layers of the epicuticle? (4)
Cement- outermost layer
Wax- layer under the cement
Outer epicuticle
Inner epicuticle
What is the exocuticle?
non-living layer under the epicuticle
What is the endocuticle?
non-living layer under to exocuticle, above the epidermis
What features are found in both the exocuticle and endocuticle? (3)
non-cellular
made of chitin to provide strength and rigidity
made of resilin to provide flexibility
What is the epidermis layer, and what its function?
innermost, living layer
secretes substances involved in molting
What are sclerites?
plate of the body wall surrounded by sutures or membrane
What are sutures?
the line of fusion of two plates
What is the membrane in the exoskeleton?
a thin and pliable cuticle
What are setae?
hair-like projections of the cuticle that arise from a trichogen cell
What are scales, and an example?
flattened setae that serve a “covering” purpose
Ex- wings of butterflies and moths, or bodies of silverfish and beetles
What are spines, and their three functions?
Outgrowths of the cuticle, not produced by the cells
helps in grasping, clinging, and protection
What makes up the sensory segments of the head? (3)
Eyes
ocelli
antennae
What makes up the feeding segment of the head?
paired mouthparts
What 5 different types of mouthparts are there, and an example?
chewing- grasshopper
piercing and sucking- mosquito
sponging- housefly
siphoning- moth and butterfly
chewing and lapping- honey bee
What 3 segments make up the thorax?
Prothorax (closest to the head)
Mesothorax
Metathorax (closest to the abdomen)
What kind of modification lets an insect run?
Cursorial leg modification
What kind of modification lets an insect swim?
Natatorial leg modification
What kind of modification lets an insect jump?
Saltatorial leg modification
What kind of modification lets an insect grasp?
Raptorial leg modification
What are three facts about insect wings?
An important development
Wings are outgrowths of the cuticle
Type and size vary, depending on need
What are the layers of the wings?
Veins surrounded by a cuticle
What two veins are found in the wings?
Longitudinal vein and cross-vein
What five types of wings exist?
membranous wings (flies with haltere)
tegmina (leather-like forewings- cockroach)
hemelytron (half-wing; forewing for true bugs)
Elytron (hardened front wing)
Scaled covered wings
What 3 things are found in the abdomen, and what is not found?
Has no walking appendages
Possesses the ovipositor- egg-laying device
Possesses the stinger- a modified form of the ovipositor
Cerci- sensory structures
What does the glandular setae do?
produces secretions involved in protection or communication
What does the ocelli do?
light detection
What is the ommatidium?
single eyes that form the ommatidia (compound eye)
What does the ommatidium do?
Detects a color
What kind of vision do insects have?
Developed to be sensitive to changing patterns and movement, not for highly detailed views
How do insects perceive color? (3)
Insects can see higher wavelengths than humans
Humans can see lower wavelengths than insects
Most cannot see red
What does the mesothorax hold?
Forewings
What does the metathorax hold?
hindwings
What are the parts of an insect’s leg?
Coxa > trochanter > femur > tibia > tarsus > pretarsus
What are halteres? (2)
balancing organs to help the insect fly
Hindwings are modified into halteres
