Earthworm and Cockroach Necropsy

What are we looking for in the earthworms?

Monocystis (protozoan)

What are the steps to dissecting an earthworm?

1) Cut into the anterior dorsal side of the earthworm (darker side with no chaetae)

2) Use pins through the body to hold the incision open

3) Remove one of the seminal vesicles, put it on a slide and gently crush it with a coverslip

4) Examine the slide under the compound microscope for Monocystis

5) Record the number of Monocystis found in all 6 seminal vesicles

What is this?

Monocystis

What are these?

A-B. Isolated sporocysts C. Sporocysts in tissue

What pinworms species are we looking for in cockroaches?

Leidynema appendiculata and Hammerschmidthiella diesingi

What are we trying to determine?

See how many roaches are infected, whether the pinworms are site specific, and examining whether the relative abundances of infection differs based on sex and if size is correlated with infection intensity

What are the steps to dissecting a cockroach?

1) Cut off the largest leg (3rd) and measure the tibia; record the length

2) Cut off all of the remaining legs

3) Pin the roach ventral side down in a dissecting dish and use pins to pin the wings and thorax.

4) Cut through the bottom of the abdomen near the side of the body until the anterior portion of the thorax is reached.

5) Lift and remove the terga (outermost layer)

6) Remove the muscle and fat bodies to expose the alimentary canal

7) Cut off the head, remove the crop and remove the rest of the digestive system, removing the colon from the rectum

8) Cut off the crop and place in a petri dish with water, examine under a dissecting microscope for pinworms

9) Do the same with the mesenteron and the colon

What are the things we were dissecting out?

Crop, mesenteron, and colon

What are these?

a. Whole Pinworm b. Anterior of L. appendiculata c. Anterior of H. diesingi