To begin with, I’m neither the quintessential lumper nor splitter. A lot of the discussions regarding the subject seem come down to a general misunderstanding of what a subspecies is, and in what ways the information provided by giving a population subspecific status is useful. Dell and I had a long, in depth conversation about this a few nights ago (beer and a good cigar always invoke our powers of thought…and conversation…).
So… what IS a subspecies, then? There are essentially two “types” of subspecies: primary and secondary, for the purposes of this paragraph. Herein, “primary” subspecies will be considered to include populations within a species which have achieved a relatively high degree of phenotypic and genotypic stasis over a given geographic area through selection. These populations blend or meld (what is technically referred to as primary intergradation) in areas of transitional habitat or geography with adjacent populations which have also undergone a specialization and relative character stasis within their given geographic region. These primary subspecies are, in my semi-educated opinion, what we see with MOST triangulum populations from Canada to Ecuador and Venezuela, and from Maine to the Great Basin.
“Secondary” subspecies, however, have arisen in allopatry through selection and genetic drift (etc.), and come back into contact with one another following some ecological or geological event. When formerly separated populations reunite, the degree to which they intergrade is highly variable. They may breed together as if they were never separated, only breed occasionally, or not breed at all. In the first case, it’s easy for us to define that both populations remain part of the same species, just as it’s easy for us to define them as belonging to separate species in the last case. It’s that middle-of-the-road situation that causes us grief. These secondary subspecific processes are, to me, what’s likely happening between triangulum proper and elapsoides.
So, what’s the utility of subspecies names if they really just meld from one to the next across the species geographic range? Simple. They provide us with clues (major clues) about the animal’s natural history. When we see a reference to Lampropeltis triangulum syspila, we note that the animal has a certain appearance, is an inhabitant of east-central US, prefers to secrete itself beneath rocks and logs in grassy glades and forest clearings, and feeds primarily on skinks, small snakes and rodents. If we see a reference to L. t. celaenops, we note that the animal has a certain appearance, is an inhabitant of the southwestern US, lives in arid to semi-arid grasslands and canyons, and feeds primarily on Sceloporus lizards and small rodents. These are very useful bits of information, and provide us with a much clearer picture than just labeling them all Lampropeltis triangulum.
Please feel free to share your thoughts, compliment me, or disagree!
-Cole
L. t. multistrata – Thomas Co., NE
