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GARDEN SNAIL LAB
The common garden snail is an ideal animal tor simple, introductory exercises in behavior. They have a
limited behavioral repertoire. are a convenient size tor handling and observing, are slow-moving, are easily
housed and maintained. are not 'shy', and will behave under crowded and noisy laboratory conditions.
I
They are normally inactive during daylight and dry conditions. If the snail is quiescent at the beginning of
the laboratory session, 'wake them up' by immersing in tepid water for a few minutes. As soon as it shows
signs of activity, remove from the water, dab it dry, and start your work.
They feed by means of a toothed radula which they sa-ape fragments from living plant material.
OBSERVATION 0 LOCOMOTION '
sheet of glass
damp and stand
dissecting microscope
Matenats:
Methods :
Put an actively moving sna~ on the center of a sheet ot glass. When it has taken a finn hold of the glass
surface and is moving with the foot fully extended, slowly tum the glass over and damp it finnly in the
horizontal position. With the dissecting scope in low power, examine the foot of the snail as it moves and
observe the ripples of muscular contractions as it moves. Count how many ripples it has in one minute
(use 30 sec. counting times and multiply for 1 min.) You may need to take several readings and average.
Rate per minute:_ _ _ __ _ __
RESPONSES TO TENTACULAR, DORSAL, AND LATERAL CONTACT
Materials: Probe
When specimen is moving freely on a surface, touch the snail GENTLY with a blunt probe. Compare light
touches on one part of the body with another part. Do you expect the animal to tum away or into the
stimulus?
_ _
Use the same intens•. f 3CJie of the habituation section to evaluate the response of the retraction.
Anterior tentacle touch :_ __ _ _ _ _ __ __
Posterior tentacfe touch
Lateral body touch :_ _ _ _ _ _ _ __ _ _
Dorsal body touch :_ _ _ _ _ _ _ _ _ __
Did the specimen turn into or away from the stimulus :_ _ _ _ ___,_
HABITUATION TO VIBRATION :
Matenals : Weight (book . etc.)
RIJer
Clock wi1h second hand
Desktop
Put a snail on the mtddle ot the desk top and wart until'' ts fully extended and movmg freely. Drop the
weight from a small known height on to the desk top at a known distance from the moving animal. Repeat
a number of times at regular Intervals and record the responses of the animal
The degree of response of the arnmal can be placed on an tntensity scale as follows: whole body
retracted=10. body only partially retracted=6. both tentacles only retracted+4, only 1 tentacle retracted=1 .
no response=O. Repeat testing until there is no response. meaning the animal has habituated.
Height Distance
Response
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Did your animal ever habituate?_ _ _ _ _ How many trials did it take?_ _ __
FEEDING BEHAVIOR :
Materials: Sl'leet of glass
clarT1> and stand
dissection microscope
container of cornstarch diluted with water
Methods: Paint one side of the sheet ot glass with a very dilute wash of the cornstarch and water. Put the
snail in the center of the glass and wait until !he animal is moving freely. Gently invert the glass sheet and
damp so that you can observe it under the dissecting scope. The action of the radula can now be
examined--count number of licks per minute. observe the side to side ·scanning' motion of the head, and
the behavior of the anterior tentacles.
Ucks per minute :_ _ _ __
Did you see the head move side to side? _ __ _
Did the anterior tentacle seem to be involved in sensing the food? _ __ _
RESPONSES TO DIFFERENT SUBSTRATE TEXTURES AND CONTOURS :
Materials: Pieces of modeUng day w1th pins set in at various distances
Methods: Release an active snail co surfaces made up of different distances of pins. Try surfaces made
up ol1mm. 2mm. 3mm. and so on unt~ the snail no longer regards the points as a surface. Observe how
the production of mucus might change. how the snail might exploit the sides of the pins. and at what
distance the locomotion stops.
1 mm
2 mm
3 mm
4 mm
_ _mm
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