Text and illustrations
below are excerpts from an article, entitled:
Toolbox for Working With Living Invertebrates
to be published in
Proceedings of the Association for Biology Laboratory Education
(ABLE), vol. 26, 2004
I. FleX-Acto Invertebrate
Purpose of tool:
spatula-like tool enables rapid detachment and minimally destructive removal of
small, living organisms that adhere to irregular or smooth surfaces in both
field and lab contexts. The tool is especially well suited for removal of
snails, snail egg masses, planaria, leech cocoons, caddisfly larval tubes, and
other small, delicate organisms that adhere to rock, wood, or aquarium surfaces.
Additional desirable features of this tool are that it (a) has a very thin,
flexible blade, (b) has an adjustable blade length, (c) floats, (d) is
inexpensive, (e) is made from recycled materials, (f) is safe to use, and (g)
may be re-configured in a variety of blade shapes and
Craft sticks (popsicle-type sticks; available at most craft stores
in several lengths and colors)
New, single-edge razor blade
Very flat, smooth work surface for cutting (such as smooth
countertop, metal or glass plate)
Flexible, snap-top lids from margarine, sour cream, yogurt, or
other re-sealable container [Note: Light colored lids, such as
white or yellow) are preferred because they improve viewing contrast while
dislodging dark-colored organisms.]
Thin rubber bands (e.g., Universal or Plymouth brand #8 rubber
bands; 7/8 in x 1/16 in x 1/32 in)
Assembly and use of this
- Use scissors to cut the
flexible plastic lid into long, rectangular strips. Each strip should be
about 4-7 mm in width and about 5-6 cm in length.
- Lay one of these flexible
strips on a very smooth (non-scratchable) surface or counter top and tightly
grip the distant end of the strip with your thumb and forefinger. The free
end of the strip should lie flat on the counter surface pointing toward you.
- Using a brand new
single-edge razor blade held in your other hand, place the edge of the razor
blade in contact with the free end of the strip, several mm from the end (Fig.
2A). The cutting edge of the razor blade should be positioned as follows: (a)
tilted at a steep angle (Fig. 2B), (b) parallel with the cutting surface, (c)
directed toward you, but (d) positioned well away from any part of your body.
Figure 1. Making beveled blade for FleX-Acto tool.
- With the razor blade tilted
at this steep angle, pull the blade slightly toward you and downward while
using your other hand to firmly and slowly pull the strip away from you. The
blade should smoothly slice through the strip creating a beveled edge at the
very end of the strip (Fig. 2C). Make a similar beveled edge at the other end
of the strip.
- Now, place the finished,
beveled strip in between two craft sticks with one beveled end extending about
1 cm beyond the ends of the sticks. Make a second beveled strip with a
different shape or color and sandwich it between the sticks at the other end
Finally, wrap each end of the
stick tightly with a thin rubber band (Figs. 2D & 3A). Assembly time per tool
is about 5 min. Estimated cost per tool is less than 5 cents.]
Assembled FleX-Acto tool and accessory blades.
Suggestions for using this
- To remove aquatic organisms
from the underside of rocks or submerged objects, lift the rock out of the
water and invert it (Fig. 3B). Then, gently slide the beveled end of the strip
under the organism, making sure that the plastic edge remains in contact with
the substrate beneath the organism that you are attempting to dislodge. Use
the tool to transfer the organism to a storage container with water. Replace
the rock, as found.
Photos of assembled FleX-Acto tool (A) and its use in the field (B).
- If the organism is attached
to the side of an aquarium, then you may also need a disposable, large-bore
plastic pipet to quickly suck up the dislodged organism before it reattaches.
Then, transfer the organism to another container for viewing or storing.
- You can change the
flexibility of the beveled strip by changing the distance that the strip
extends beyond the end of the stick. Longer, stiffer, narrower, or bent strips
may be useful for detaching animals from hard-to-reach areas. With practice,
beveled ends with other shapes and angles can be made (Fig. 2E).