Module 2 Flashcards
Body regions of insect
Head
Thorax
Abdomen
Plates on the bottom side of the insect
Sternum
Plates on the top side
Tergum
Top part of thorax
Notum
Bottom plates of thorax
Pleuron
Antannae
Pair of appendeges that come out of an insects head and can be used to identify insect type
Have sensilla that process stimuli
Can detect many things
Allow insects to perceive flight speed
Can hold onto partner during maiting
Compound eyes
Made up of ommatidia
All images perceived by ommatidia combine to make one image
Each one can be considered its own eye with a lens and a crystaline cone
Pigment cells
Adapt the photosensitivity of the eye
Ocelli (simple eyes)
Cuticle is curved onto a lens
Connected to extedned retina that connects to many sensory cells
Appear as small swellings on the head
Labrum
Protects the other mouthpart sructures
Mandibles
Have powerful muscles and are the largest part
Used to cut tear and crush food
Can be used as tools or weapons
Maxillae
Less powerful than mandibles but positions food towards mandibles
Labium
Bottom of insect mouth
Used with maxillae to modify food
Can be modified (Dragonfly modified to be strong and piercing)
Palps
Can be found on the maxillary and labium
Allow insects to smell and taste
Mouthpart adaptations for liquid food
Piercing sucking mouthparts
Siphoning mouthparts
Sponging mouthparts
Chewing-lapping mouthparts
Piercing sucking mouthparts
Used by insects to pierce food and access food within
Associated with salivary glands to break down and digest food
Usually insects with this have muscular sucking pumps in their heads
Siphoning mouthparts
Allow insects to siphon nutrients through a long proboscis
Only found in butterf
Sponging mouthparts
Known as a labellum
Covered in many grooves that allow the uptake of liquid food by capillary action
Chewing-lapping mouthparts
Unique to bees
Allow them to feed on nectar
Works like a tongue to bring up nectar
Bees also have mandibles for feeding and other tasks
Parts of the thorax from closest to head to farthest
Prothorax
Mesothorax
Metathorax
Each segment has legs but only the last two hang wings
External genitalea is found in
The posterior end and used for mating
Adeagus
Male sexual organ
Protected in body until mating
Contains penis and claspers
Claspers
Allows male to hold onto female
Ovipositors
Used to deposit eggs
Can be external
Can have sensory structures to detect cues
Telescoping ovipositors
Retract eggs between laying sessions
Parasitic ovipositors
Very long and used to insert into insects deep within plant tissues
Cerci
Snesory appendeges at the end of the abdomen
Can detect air currents of predators approaching from behind
Can be modified to make pinsirs
Can be used for repro (claspers)
Insect digestive tract
A single complete tube known as the alimentary canal
Alimentary canal
Only a single cell layer thick, rests on thin fibrous extracellular matrix of tissue called a basement membrane, surrounded by the gut muscles
Insects that feed on solid food
Alimentary canal is
Wide short and straight
Strong muscles to prevent abrasions
Insects that feed on liquid food
Alimentary canal is
Long narrow and convoluded to maximize surface area for liquids
Plant feeding insect
Have little nutrient containing food like leaves and stems
Little need for alimentary canal to be large so they are generally short
Animal feeding insect
Need large food storage capacity and a large alimentary to sustain themselves when resources are scarce
Insect digestive system regions
Foregut
Midgut
Hindgut
Foregut
Where food is digested and broken down
sometimes food is stored there
Midgut
Where most digestion occurs
Hindgut
Absorption of water salts and other nutrients happens in the hindgut
Foregut and hindgut have a
Cuticular lining that must shed during a moult
Digestion begins with
(digestion steps)
The help of the salivary glands
It is turned into a bolus and passed into the pharynx
It then moves through the esophogous and into the crop where it is stored
It is then moved into the proventriculus where it can be further broken down by its many teeth (mostly common in solid and fibrous diets)
Passed into the midgut where it is mostly broken down into simple molecules by enzymes
Midgut pH is between 6 and 7.5
Midgut absroption is maximized by outpockets on the front end of the midgut called the gastric caeca that make more space
Midgut has the peritrophic membrane and keeps the gut protected and compartmentalized (must be secreted constantly while insect is feeding)
Malpighian tubules are extensions of the hindgut that permeate into the insects body cavity. They remove nitrogenous waste and maintian osmoregulatory balance (distal ends remove substances in the insects blood. Anything that is removed is reabsorbed later before excretion)
Hindgut cocentrates waste and absorbs water. salt and other nutrients. After absorption, everything else exits the rectum via the anus as frass (waste).
Symbionts
Organisms that help with metabolic processes
Can include protists, bacteria and fungi
Helps digest material that insects cant handle on their own
Can detoxify poisons
Can be moved from insect to insect via either vertical or transovarial transmission
Osmoregulation
Terrestrial insects release concentrated nitrogenous waste called uric acid
It has low toxicity and can be excreted with very little water
Fat body
Network of fatty tissue that is in the abdominal cavity
Helps metabolize large macromolecules
Also essential for nutrient storage (insect draws on it during non-feeding parts of its life cycle)
Contributes large amount of insects weight
Hemolymph
Insect blood
Colourless and contains nutrients
Most of an insects body weights
Does not have hemoglobin so cannot transport oxygen
Has distasteful chemicals to deter predators
Hemocoel
Where blood is stored in the insects
Not blood vessels
Two parts of hemolymph
Liquid plasma
Hemocytes
Plasma
Distributes nutrients and hormones
Hemocytes
Main part of insects immune systems
In charge of coagulation to repair injuries
Dorsal blood vessel
Allows hemolymph to move into the vessels and circulate
Dorsal diaphragm
Supports the dorsal blood vessel
Ostia
One way valves in the dorsal blood vessel
Hemolymph travel pattern
Pumped out towards head and then travels back towards the rest of the body through muscular contractions of the ventral diaphragm
Movement of hemolymph into appendages is done by additional pumps at the appendage
Gas exchange is done by
Trachea
Tubes reinforced by cuticle
Cuticular lining of trachea is reinforced by
Spiral openings that prevent it from collapsing and still allow mobility
These linings are shed when the insect moults because they are cuticular
Tracheoles
Smaller branches of trachea that are in contact with tissue
Higher amount in tissues that have a higher demand of oxygen
Spiracles
Openings in the insect body that allow interaction with the outside world
Found in the thorax and abdomen
Have filters and valves that allow for gas exchange without letting Microparticles in or water loss
Spiracles being closed means the insects are “holding their breath”
Air sac
Increase volume of air moving into trachea and can be involved in sound production
Can also be compressed to allow for more room during a moult
Terrestrial insects have an
Open trachea system
Aquatic insects have a
Closed tracheal system
No spiracles
Gas exchange through the thin cuticle
Some aquatic insects have
Gills
Leaf like extensions of the body with a network of cuticles under
Gas exchange system works from
Diffusion of gases from high to low concentration
Oxygen is taken (in or out)
In by tracheal network
CO2 is taken (in or out)
Out
CO2 can also move through the
Tissue through diffusion and into the spiracles
Water is (lost or gained)
Lost during gas exchange
Discontinuous gas exchange happens during
Inactivity
Spiracles are kept close and gas exchange is through diffusion
Tracheal network in larger insects is proportionally
Larger because diffusion on its own is ineffective
Long thin body plans
Allow for a short distance between spiracles and tissue
