by Laura Cameron

Created on: January 26, 2009

Ever wondered what those little pests called cockroaches are really made of? Thought of trying to dissect one yourself but didn't know how to do it? Well, the answer is here. In the following article I will discuss two methods of dissection for cockroaches and 2 methods for killing them, one more humane than the other.

If taking a more scientific and humane approach, one method is to knock out the cockroach using carbon dioxide (dry ice) or nitrogen. From here, you may continue with the dissection knowing that the subject will not feel any pain.

The first step to dissecting a cockroach is to gather a tray and fill it half way with a firm dissection gel. Then, place the cockroach backside down against the gel and using pins pin down all both of its wings, and then remove all 6 of its legs. Extra pins may be inserted through the wings to further stabilize the cockroach. Next, take the scalpel and make ventral cuts along the abdomen to remove the exoskeleton (using medical scissors). Once the exoskeleton has been removed, one must remove the fat body using forceps to expose the internal organs of the cockroach. Some of the major structures inside a cockroach are the crop, gastric caeca, midgut, Malpighian tubules and hindgut.

Another method of dissection is to first kill the cockroach in a jar which is far less humane than anesthetizing it first. Afterwards, you would precede to remove the head from the cockroach to separate it from its internal organs. From this point forward, one would follow the steps mentioned above to begin removing the exoskeleton.

Ever wondered what their internal organs actually do? Well, the crop, which is an enlargement of the foregut, serves as a temporary storage area for food. This is where digestion of the complex sugars begins, which is aided by the bacteria found in the gastric caeca (elongated pouch at the beginning of the midgut). The Malpighian tubules are actually the primary organs of the excretory system. Their function is to remove nitrogen-containing wastes and regulate water and salts in an insect's blood, called hemolymph. Contents from the midgut and Malpighian tubules empty into the hindgut, where final resorption of water, salts, and nutrients from the feces and urine takes place before excretion.

Now when your faced with the question of "How does one dissect a cockroach" not only will you be able to respond with 100% accuracy, you also will be able to include a few fun facts about the function of the major structures found inside a cockroach.

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