Module 4 Flashcards
Passive dispersal
Movement by assistance of other things like wind/water/ other insects
Human assisted passive dispersal have led to the addition of
Invasive species
Passive dispersal requires
Less energy
Passive dispersal works best in
Small insects
Passive dispersal downsides
Insects can’t choose where they go
Can die during journey (have high repro rates to combat this)
What is used most in passive dispersal
Wind
Phoresy
Symbiotic relationship where a smaller individual is transported by a larger one
Globalization and trade
Have allowed for the addition of invasive species
Active dispersal
An organism moves itself
Norm for insects
Unique modes of locomotion
Water striders use hydrophobic hairs at the end of legs which create a barrier between them and water, allowing for them to not break water tension, increasing buoyancy
Dragonfly nymph movement
Gas chamber propels the nymphs forward in water
Mosquito pupa movement
Somersault head over tail underwater to move
Rove beetle
Can escape predators in water using Marangoni propulsion
Marangoni Propulsion
Shoots chemical from anus that propels the insect forward by reducing surface tension
Caterpillar avoiding predation
Wheel down surfaces by curling into a ball
Insect muscles
Act in tandem with the exoskeleton
Muscle is connected to inner surface of exoskeleton where cuticle is strengthened by apodeme
Resilin
Elastic tissue that works like tendons in vertebrates
Insect muscles are very
Efficient
Power of a muscle is dependent on
Area
Entire body mass of insect is associated with
Volume
Volume decreases
More than area
This shows insects are able to be strong despite their body size
Larval insects move through a
Hydrostatic skeleton
Muscles are attached to body cells
Turgidity
Body shape is determined by muscles
Contraction of these allows for movement
When muscles contract in one part of the body, another part relaxes, muscles contracting and relaxing creates an undulating or sinusoidal movement
Hooks and spikes are also used
Insect larvae use this underwater as well
Parts of the insect thorax that have appendeages
Prothorax
Metathorax
Mesothrox
Insect segments
Coxa (closest to insect)
Trochanter
Femur
Tibia
Tarsus
Pretarsus (fartherst to body)
Tripod gait
Keeping all legs on the ground at all times
Provides stability
Cursorial
Running legs
Well developed femur and tibia
Allows insects to cover a lot of ground quickly
Slim leg allows for increased stride amount
Raptorial
Spines on femur and tibia
Used to grasp prey
Preying mantis
Fossorial
Tibia is flattened with sceleritized ends to allow insect to burrow
Tarsus are greatly reduced
Saltatorial legs
Femure and tibia are long to allow the insect to jump
Natatorial legs
Flattened legs with rows of cita to allow the insect to move in water
High surface area
Proleg
Modified extensions coming out the body
Lepidoptera, hymenoptera, and diptera have this in their larvae
Have hooks to allow for gripping
Not actually legs
Paleoptera
Cannot fold their wings into their body (dragonflies)
Neoptera
Can fold their wings using folding lines
Wing folding
Protects the wing from damage and allows them to fit into spaces
Mayfly subimago (just before adult)
Has wings
Forewings are attatches to
Mesothorax
Hindwings are attached to
metathorax
Wing structure
Membranous structure
Membrane is made up of two thin layers of cuticle pressed together
Wing veins are hollow and contain trachae, nervs and hemolymph
Early winged insects have many
Cross veins in the wings
Sclerites
Join wings to abdoman
Grasshoppers have evolved
Tegmina
Tegmina
Scleritized wings to provide protection for the hind wings
used for steering in flight
Tegmina can also be used for
Sound
Predator evasion
Hemelytra
Having half the forewing be mebranous and the whole hindwing is membranous
Elytra
Leathery wings that are completely scleretized
Lepidoptera wings
Wings in this order are used for mimicry, protection, camo, mate attraction, insulation, and temp regulation
Achieved by scales on the wing sockets placed at an incline
Diptera wings
Hind wings are modified into halteres which are used for balancing
These structures do not assist in flight
Campaniform sensilla
Sensory structures at the base of halteres used to assist flight
Termite wings
Only reproducing ones have wings which are also shed
Water strider wings
Wings are only present in unfavorable conditions to allow the offspring to fly away to a new habitat
Direct flight muscles
Up and down strokes are achieved by muscles attached to the sclerites at the base of each wing
When the wing is moving up, the proxiaml muscle is used
When moving down, the distal muscles is used
Paleoptera use
Direct flight
Most insects use
Indirect flight muscles
Indirect flight muscles
Attached to ridges in the thoracic endoskeleton
Two groups of indirect flight muscles
Dorsoventral muscles (up stroke)
Dorsal longitudinal muscles ( down stroke)
Flight muscles are attached to
The notum and sternum within the insects thorax.
Indirect flight muscle movements
When one set of flight muscles contracts, the other relaxes, allowing for the wings to move up and down
Energy during flight
Energy is stored either in the cuticle or in the flight muscles and with each opposing stroke, energy is released
Types of wing movement
Vertical flapping motion
Rotation of wing around its base to allow for pitch control by accounting for air movement. Also allows for 3D movement rather than just up and down
Flexing for flight control
Wing tip moves in
A figure 8 pattern that allows for maximum efficiency
Different types of flight muscles and how they differ
Synchronous
Asynchronous
Differ in the amount of movements of the wing per nerve impulse sent to the wing
Synchronous muscles
One nerve impulse is one wing beat
Asynchronous
One nerve impulse is multiple wing beats
Lift in insect flight was created from
Leading edge vortexes (front-end) created on a fix point in the wing that spirals towards the tip
DPIV (Digital Particle Image Velocimetry)
Used to precisely detect the flow field of insect wings instantaneously
DPIV allows researchers to
Assess small scale physical movements and dispersals of insects
Flight mills
Insects are connected to a mill and allowed to fly under a tether in a circle
Cannot make possible predictions on dispersal from there
Wind tunnel
Studies. how insects react to external stimuli
Researchers expose the insect to a test stimulus and blow wind to allow for flight of the insect and see how they respond to the stimulus
Criteria that migration involves
Persistent movement
Relatively straight movement
No stopping of movement regardless of stimuli
Pre and post migratory behaviours
Physiological changes
Not migration
Foraging behaviour
Phoresy
Human displacement
Migratory syndrome
Predisposition to migrate when a negative stimuli is received from the environment
Pre-migratory responses
Insect populations having predisposition to allow for the organism to alter locomotory ability, resource allocation, reproduction, and survival probability
Oogenesis-Flight syndrome
Allocation for either migration or reproduction
Phases of migration
Initiation (prep for migration)
Transmigration (migration)
Termination (Migration ends)
Initiation is started by
outside stimuli such as day cycles and temperature
Diurnal (day time flyers)
Migration
Fly close to the ground and use updrafts made from warm air rising from the ground to allow themselves to glide more
Can also use polarized light to infer the location of the sun and the horizon to know where to fly
Polarized light detection is done by
Ommatidia that is adapted the compound specifically for this
Locusts
Pest migrators that are migratory grasshoppers that migrate because of overcrowding
They move in swarms and destroy vegetation
Continue to harm agriculture
Polypheniesm
A gene has two variations that can be activated (IE will the grasshopper stay or migrate depends on the cue)
Primary mode of locust management
Use insecticide but this is costly and can harm outside organisms
Locusts arrive
After dry seasons during rapid vegetation development
It is important to keep track of when locusts appear before they do to prevent swarming
Monarch butterfly migration
Moves from southern Canada to Mexico due to temperatures
Migrating monarch butterflies
Suppress juvenile hormone in order to prevent reproduction
When arriving to overwintering sites
monarch butterflies
Adults stay inactive for 4-5 months
Cluster together for warmth
Monarch butterflies need what to survive the migration
Stored fat reserves
Before the the return migration
Monarch butterflies
Egg production and overall activity increases
On the way back from South America monarch butterflies
Lay eggs in milkweeds and die shortly after
First generation of caterpillars migration for monarch butterflies
Will feed and then turn into butterflies before flying north and stopping to reproduce
Whole generation of monarch butterflies take
2-5 generations
Monarch butterflies are able to visit
The same sights as there ancestors when they migrated
Can be because of genetic memory passed down
Or sun location
Or air currents
Or magnetic field orientation
Or chemical markers left by previous generations on plants
Or Geological features
Monarch butterflies concerns
Migratory success is worse because of destruction of habitat
Warrants conservation
Monarch butterflies importance
Important pollinators
