Lecture 9 Flashcards
Guts
Three types of gut, fore gut, midgut, hindgut
Foregut-serves for ingestion, storage and grinding
Midgut-digestion and absorbtion
Hindgut- osmoregulation(drying out) , absorbtion, extcretion
*Foregut and hindgut are exoskeleton so they are also molted
Proventriculus
grinds food to small bits
Gastric caecum
Absorption of water, secretion of enzymes, wide space
Peritrophic membrane
In most insects except liquid feeding insects. Without it you could be injured so it protects inside
Malpighian tubules
The differences between mammalian kidneys and malpighian tubules is that kidneys aren’t connected to digestive tract while the tubules are connected to insect digestive tract. Our kidneys filter out our blood.
Where are the malpghian tubules located?
In the Midgut
Excrement
Also known as frass
How many malpighian tubules are there?
2-200 in one insect
Filter Chamber
A modification in sap-sucking insects. Water is absorbed very quickly and expelled quickly.
Reproductive system
Similar to vertabrates
Both gametes are haploid and unicellular
Insects are mostly bisexual and biparental, so one egg and one sperm fuse to may diploid zygote
Some can reproduce by parthenogenesis, form of asexual (virgin birth)
Some alternate between sexual and asexual. Not all generations can make males or no males might ever occur.
Reproductive History
- Sperm used to just swim to females body since primitive arthropods lived in water.
- To adapt to terrestrial life, they had to engage in external fertilization to protect sperm
- Myriapods and insects encapsulate sperm with a watertight protein sperm
- These packages of sperm are spermatophores
- Myriapods and primitive hexapods like collembola, males leave spermaphores
- Silverfish and bristletail lead mate to spermaphores
Male Reproductive System
- Testes located back of abdomen
- Hundreds of follicles where sperm are produced in the testes
- End of follicle are groups of germ cells (spermatogonia) and mitosis leads them to be spermotocytes(bigger)
- These spermotocytes migrate to basal end
- Mature sperm collects in seminal vesicles and there are other ducts called vas deferentia that lead it away to ejaculatory duct that leads out body through organ called aedeagus
- There are also accessory glands (short ducts) near testes that manufacture seminal fluid (nourishes sperm) and produce spermatophores(pouches of sperm)
Female Reproductive System
- Consist of ovaries, and ovarioles
- In egg production, germ cells go under mitosis to make oocytes (eggs). These go into meiosis and increase in size
- Microphyl allows sperm to enter
- Once mature egg goes to genital chamber (bursa copulatrix) through the lateral oviduct. The male deposists spermaphore in this place.
- Peristaltic contractions used to move this package into spermatheca where it is stored
- Spermathecal gland produces nutrients to keep sperm alive.
- When egg enters spermatheca, it stimulates release of sperm and theyll enter through the microphyl
- Fertilized when nuclei of sperm and egg fuse
- Oviposition(egg laying) is after this fertilisation
Cement
Goo that sticks to hair
Head lice sticks to hair
ootheca
egg case produced by females
Varies in insects, some carry until it hatches, some leave it in an area, or even shoves it back in body (cockroach)
