Identification keys (xDelta-l)

Robin Leech robinl at NAIT.AB.CA
Fri Jun 16 08:20:06 CDT 1995

Having made a number of keys for spiders, and after having instructed
students on the best way to make keys for plants and animals (the old
fashioned way!), I suggest that "most common" is not the best criterion
for "sorting out" in the beginning of a key.

The problem with "most common" in collections is that this often reflects
the abilities of the collectors (animal groups) or the observers (plant
groups), and may not be a reflection of real commonness or rareness.

I have a very keen "beetle" friend in Ottawa, and his perception of common
or rare for particular species in no way resembles that of other "beetle"
people.  My friend is one of the keenest collectors I know, and "susses
out" various beetles and collects them in numbers, whereas others cannot
find them and, therefore, think them rare.  The numbers of specimens of
certain species of carabids in collections bear out the perception of most

In my case, I feel that GRYLLOBLATTA CAMPODEIFORMIS is a common insect,
as I am able to find it in many places in British Columbia.  My opinion
is not held by my friends, some of whom have been collecting at my side
and were unable to find GRYLLOBLATTA.

I suggest that "distinctive" species which have one or more distinct
features (larger, hairier, fewer awns, fused petals, etc.) that set them
off from other members of the taxon (family, tribe, genus, or whatever) be
"selected out" at the beginning of the key.  The main reason for this is
that if you "carry the odd ball" through the key, you find yourself
continually making accommodation for it, and as a result, the key becomes
more cumbersome.

Robin Leech

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