names/systematics

[Chris J. Durden]

  I agree it is mostly subjective. In each major group an experienced
student develops a feel for specific level and generic level differences.
Much of this comes from a mentor and may be useful or arbitrary.
  The key is to figure out how the individuals of a species recognize
eachother. This is possible with sympatric overlap of more than one
species, although the characters actually used may be pheromone, sound, leg
or facial pattern - not easy for us to measure. It is impossible with many
disjunct populations, because the need for discrimination has been lost.
Here it may be impossible to assign a disjunct outlier to the correct one
of two or more  sympatric sibling species, hence the taxonomic mobility of
some subspecies and the distinct need for the subspecies concept.
  If interspecific hybrids are found in the wild, there is bound to be a
good ecological reason why. These hybrids force rexaminatoin from time to
time of the status of the parent "species". I am thinking of the wild
hybrids of the VICEROY with other species of *Limenitis (*Basilarchia*)
which tend to occur only where subspecies of either or both parents overlap
or transition, a phenomenon that would be missed by someone who ignores
subspecies. Fitness of interspecific hybrids may be little less than than
fitness of interracial hybrids, hence both survive in competition. Rearing
in the lab shows you can mate most combinations in this subgenus
successfully. It is survival in competition in the wild that counts.
  There are other species pairs (in *Mitoura* for instance) that produce
adult wild hybrids when both parent species are rare, but not when both or
one are common. This again is a survival issue, and selection is the key.
One is tempted to adopt the definition: a species .... occupies a niche. So
what is a subspecies? A subniche occupier?
  Discrimination of genera is even more arcane, but if we are finding
intergeneric hybrids such as BEEFALO - *Bos* x *Bison*, either species,
there is probably something wrong with the genus as it is now drawn. This
intergeneric hybridization can be used to evaluate the reasonableness of
butterfly genera too. I would hesitate to separate species that
occasionally hybridize or can be made to hybridize, at even the subgeneric
level.
  Families are even worse because we may feel comfortable with a particular
family and know it well, then new work demonstrates that its member species
are polyphyletic. If convergence is tight it may be difficult to define the
split families in a way that most biologists can be comfortable with.
  Most butterflies present no problems, but there are notoriously difficult
genera such as *Speyeria* and *Amblyscirtes* that are not impossible but
need much more study than they have received. The study of these difficult
genera will do much to educate us about what the elusive species is.
.............Chris Durden