Insect Dissection Lab (III)

Insect Physiology (Ento 306)
Note that the malphigian tubule tips are attached to the rectum. This is termed the crypto-­‐
nephridial arrangement.
Estimate what % of the caterpillar body cavity is made up of the caterpillar gut
________% of body cavity
Nervous system
Locate the caterpillar’s ventral nerve cord. Identify the abdominal and thoracic ganglia.
Draw the entire dissected caterpillar under low magnification highlighting the nerve cord and
label the ganglia. Do not include the gastrointestinal tract, trachea, or fatbody.
Tease or cut open the caterpillar’s head capsule and locate the brain.
Dissection of the Tobacco budworm moth
External features
Draw the moth’s head and label the following features:
-­‐ Labial palps
-­‐ Proboscis
-­‐ Compound eyes
-­‐ Antennae
Moth hemocoel cross section
Cut off the moth’s wings and lay it ventral side up in the dissection pan. Using a razor blade cut
through the moth sagitally. Lay the two halves on their side and use a probe or forceps to
spread open the abdomen. Identify the flight muscles, trachea reproductive organs (include the
male ‘hair pencil’ or female ovarioles), and if possible the gastrointestinal tract. Draw the
moth’s internal anatomy in cross section labeling the flight muscle and reproductive organs.
Estimate what percentage of the body cavity these two sets of tissues occupy.
__________%
Think about the generalized anatomy of a grasshopper or cockroach compared to that of
the caterpillar and moth. What does this say about the behavioral ‘priorities’ of these
different organisms?