3 - Aerial locomotion Flashcards
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Beetles’ wing structure
Forewings are modified as protective dorsal shield (ELYTRA)
Hind wings are the only functional wings - longer than the ELYTRA and folds underneath it
Flies wing structure (10)
Posterior pair of wings are reduced to HALTERES (small dots) and assist with performance and stability
Flight - structure
- wings are connected to thorax via complex join (wing hinge)
- join contains resilin
Resilin
Highly elastic protein that allows for rapid sustained mvmnt
Dorsal side of insect
Notum
Ventral side of insect
Pleuron
How do taxonomists identify insects?
Use the configuration of the veins and specific landmarks to obtain important taxonomic keys
Wings structure
Flexible and have multiple veins with circulating hemolymph
Hemolymph
a fluid equivalent to blood in most invertebrates, occupying the haemocoel
Optimal functioning of cells in wings require?
That nutrients, waste and signaling molecules be transported into and out of the wings via the hemolymph.
Flight aerodynamics
Uplift & drag
Wing loading
The ratio of body mass (or size) to wing area - provides a measure of the energetic costs of flying in an animal
The larger the wing loading …
The higher the costs to fly - insect becomes too heavy for its wings.
Low wing loading
Large wings relative to body size - found where long sustained periods of flight required
Why are wings smaller in complex vegetation?
To increase maneuverability - large wings are cumbersome in complex habitat structures
Cumbersome
large or heavy and therefore difficult to carry or use, slow and inefficient
Wing loading equation
Wing Loading = body mass (g) / wing area (cm^2)]
Types of flight mechanisms
- Indirect flight
- Direct flight
Indirect flight mechanism def
Muscles are used to raise and lower the wings. The thorax deforms through this process causing the wings to move up and down
Indirect flight characterized by
- Two opposing set of muscles
- Flexible thorax
- Energy-efficient flight system
- Synchronous or Asynchronous flight muscles
(Most insects)
Synchronous muscles def
- A nerve impulse is required for each and every contraction
- This limits the rate at which the muscles can contract, because it takes time for the physiological processes associated with a nervous stimulus to run their course.
Asynchronous muscles def
- Do not require a nerve impulse for every contraction.
- Instead, a nerve impulse now and then is all that is needed to keep these muscles contracting with regularity.
- Wings beat faster than neural transmission
What insects have asynchronous muscles and why?
bees, flies, beetles
- achieve very high wing beat frequencies
Direct flight def
Muscles are directly attached to the wings and serve to raise and lower them as well as to tilt their plane at different angles
