We made drawings of the head and the leg of cockroaches that were killed in 1966 (!!) and preserved in ethanol.
Finishing on external anatomy, now it's time to explore the internal beauty of insects!
Insects have completely different anatomical structures to vertebrates. Both groups are evolutionarily advanced. Take a look at insects' internal organs - each system is sophisticated, and small too!
I thought it would be really hard to cut such a small creature without damaging the organs, but it was not too bad under the dissecting microscope.
The process of dissecting a freshly-killed cricket (adult female)
Cut off the wings and the legs. Place in dorsal view.
Cut open by fine scissors. The two big bulks are ovaries full of eggs.
The more anterior part of the digestive system
(too long to fit the whole thing in the microscope screen =P)
The more posterior part of the digestive system and the reproductive system
Underneath the digestive system is the central nervous system (CNS)
What? Isn't this cricket facing us dorsally? Yes, insects have their circulatory system (heart) on the back and their nerve center on the belly. While we have a single spinal core, insects have a pair of nerve cores.
Done. Just see how much fat this cricket has, I think crickets are quite yummy species.
Hmm, what I meant was thank you for your selfless (?) sacrifice, little cricket, which taught me a valuable lesson and unveiled a small part of the biological blackbox.
Because the preventriculus was derived from the ectoderm (same layer which gives rise to exoskeleton) of the bug embryo, it is theoretically sclerotized - which means it has hardened parts like exoskeleton! The professor said once he opened the preventriculus of an insect. The organ was internally lined with sharp teeth that made his finger bled! Those sharp teeth literally mill the big chunks of food the insect gorged into its crop.