INSECT DEVELOPMENT
Spermatogenesis
2N
2N
N N
N N N N
Germarium
Zone of Growth
Zone of Maturation
Zone of Transformation
Oogenesis
Oogonium
Mitosis to produce more germ cells
2N
2N Primary oocyte(meiosis I prophase - arrested - present at birth)
N
Complete meiosis I
Secondary oocyte(arrested at metaphase of meiosis II)
N Ovum
Onset of meiosis I
Ovulation
First polar body
Second polar body
Structure of Egg
micropyle
aeropyle
yolk spheres
nucleus
nuclear cytoplasm
vitelline membrane
periplasm (cytoplasm)
chorion
polar granules
aeropylesmicropyle
Sperm Transfer
1. Spermatophore
spermatophore
sperm
nutrients for female
Does female actually get the nutrients?
Inject male with radioactive protein
Spermatophore takes up
radioactive protein
Spermatophore passed to female
Eggs contain radioactive protein
Sperm Transfer
2. Direct intromission
Sperm Transfer
2. Direct intromission
Penes of maleArgia (Odonata)
Sperm Transfer
3. Traumatic (Haemocoelic) insemination
Development - Fertilization
germ cells
Syncytial blastoderm
Development - Germ Band Formation
Blastoderm cells migrate ventrally
Germ band
Insect Development - Gastrulation
1
2
3
ectodermmesoderm
germ band
1
2
3
4
Amnionic sac
Midgut rudiments
neuroblasts
dorsal closure
Gastrulation in Tribolium
Stage 2 -3 from previous slide
Heart
Ectoderm
fat body
tracheal invagination
somatic muscles
Ventral nerve cord
mesoderm
endoderm
Gut
Hemocoel
cleavage energids
blastodermpole cells
ectoderm mesoderm endoderm
midgut
mesodermal bands
epidermistrachea salivary glands
stomodeumproctodeum
neuroblasts CNS
gametes visceral muscles heart
somatic muscles
fat bodygonad
Fate of the Germ Layers