Lecture 2 Flashcards
integument
external envelope, exoskeleton
membrane that covers the organism
what is the role of the foregut? (4)
intake of food - mouth
storage -crop
grinding - mouth, proventriculus
transport of nutrients
what is the role of the midgut? (2)
digestion - ventriculus secretes enzymes
absorption
gastric caecum
beginning of the midgut
What is the role of the hindgut?
removal of digestive & metabolic wastes
reabsorption (of water)
malpighian tubule
filter & secrete wastes (like kidneys)
ileum
small intestine
absorption & secretion of wastes
rectum
insects have rectal pads (sponge) where water absorption occurs just before excretion
anus
where waste leaves
how does gas exchange occur?
through a series of air-filled tubes & sacs (no lungs)
vessels reach all internal organs & tissues
_____ & _____ contain spiracles at each _____
thorax & abdomen
segment
spiracle openings let ____ in & ____ out
air
CO2
what is the max amount of spiracles?
10 pairs
trachea & tracheoles
hollow tubes
coil shaped
oxygen intake & CO2 output by diffusion
(air moves out through tubes)
what are the components of the respiratory sys?
spiracles
trachea & tracheoles
air sacs
air sacs
help with ventilation
compress & fill depending on diff requirements of the body
the respiratory sys is related to the circulatory sys - T or F?
False
how does the O2 & CO2 move in the respiratory sys?
through diffusion
what sys does the dorsal heart belong to?
circulatory sys
is the circulatory an open or closed sys?
open - no veins, one tube
what is the blood of insects called?
haemolymph
what is the haemolymph responsible for?
nutrient transport
hormone transport
waste transport (metabolic wastes other than CO2)
does the circulatory sys transport O2?
no - respiratory sys does
what powers circulation in an insect?
dorsal heart & abdominal pumping
what are the components of the nervous sys?
nerve cord - ventral
brain
neurons with ganglia - each segment has a ganglion that controls nerves in a particular region
describe the brain of an insect
fusion of ganglia
what part of the nervous sys is important for movement & coordination?
neurons with ganglia
what sys do insecticides target?
nervous sys
what are the components of the integument?
cuticle & epidermis
cuticle
composed of chitin
ranges from hard & inflexible to soft & stretchable
membrane in foregut & hindgut
epidermis
produces the cuticle
base layer of integument
describe the integument of the honey pod ant
hard cuticle with stretchable cuticle to store liquid during feeding
the stretchable cuticle expands with the hard cuticle sitting on top of it
what are the functions of the integument? (7)
body support - skeleton, muscles attach to the chitin integument
movement - muscles attach which cause movement
physical protection - hard shells
prevents water loss - wax layer on top of the cuticle
sensory - spines, hairs, scales etc.
growth - moulting
pigmentation
where does pigmentation of an insect occur?
cuticle in the integument (not the epidermis)
what are the kinds of extensions of the integument?
spines
setae
spines
extension of the cuticle
epidermis creates spines
no special cells
setae
specialized cells in the epidermis
includes: hairs, sensilla & scales
what is the major diff b/w spines & setae?
spines - no special cells, cuticle extension
setae - special cells, special cells in the epidermis
scales
modified sensory organs
what are the structures of the reproductive sys in males?
testes
accessory glands
what are the structures of the reproductive sys in females?
ovaries
spermatheca - store sperm
what are the reproductive methods in insects?
sexual
asexual - parthenogenesis
haplodiploidy
sexual reproduction
fertilized embryos produce male & female offspring
asexual - parthenogenesis reproduction
females produce more females without mating
haplodiploidy
combo of asexual & sexual:
fertilized egg - creates female
unfertilized egg - creates male
describe growth in insects
incres in size
achieved by moulting
occurs in juvenile stages via moulting
no further growth during adult stages
moulting/ecdysis
casting of cuticle to allow growth
exuvia = cast skeleton (old skeleton)
metamorphosis & ex
change in form - transformatino from immature to adult phase
Ex: caterpillar –> cocoon –> butterfly
what are the steps of moulting?
- Old exoskeleton (cuticle) is digested
Occurs inside out (starts at the surface of the epidermis)
Invisible from the outside - New skeleton formed beneath old
Occurs at the surface of the epidermis - Old skeleton is shed
Break surface of the old skeleton & leaves old skin - Stretching
ONLY time when cuticle is soft - Tanning - Hardening
what stage during moulting is the cuticle soft?
stretching
how do terrestrial insects achieve stretching during moulting?
take in a lot of air to increase in size
what does it mean when you see a white insect?
it hasn’t tanned yet
will become dark brown & harden
what is difference occurs when an insect moults?
new skeleton is larger than the old one
generation
cohort of offspring from a parent pop moving through a life cycle together
instar
form of the insect b/w moults
does growth occur in an instar?
no
1st instar
out of the egg
when is the last instar stage?
adult stage (no instar is an adult)
when are the wings & reproductive organs fully developed?
as an adult
what stage is an insect in if they have wings?
adult
how is the degree of transformation during metamorphosis classified?
depends on insect taxa
what are the 3 forms of development?
ametabolous
hemimetabolous
holometabolous
ametabolous
no metamorphosis
only difference that occurs is in size
egg –> larva (lymph) - multiple instars –> adult
hemimetabolous
incomplete metamorphosis
immature insects resemble adults (not always)
egg –> larva (lymph) –> larva (multiple instars) –> adult
ex: little bug vs. big bug
ex: wings & no wings
holometabolous
complete metamorphosis
egg –> larva (multiple instars) –> pupa –> adult
Ex: butterfly of fly
what type of metamorphosis includes the pupa? & ex?
holometabolous
ex: butterfly pupa is the cocoon
