Image credit: “Semele consumed by Jupiter’s [=Zeus’s] thunder”, 1733, Bernard Picart. In Tafereel, of Beschryving van den prachtigen Tempel der Zang-Godinnen, H. Chatelain, Amsterdam.
Recently I blogged about the one thing I teach that nobody ever forgets: the meaning, and etymology, of the life-history term semelparity. If you haven’t read that post, and want this one to make sense, go ahead and read it now (I’ll wait). But it turns out that etymology I explained there might be wrong*.
A sharp-eyed reader (Jon Benstead) alerted me to an alternative etymology, laid out by James Rader in a brief letter to Natural History. According to Rader, “the notion that the semel in semelparity…has some connection with the Semele of Greek mythology looks like a bit of biologists’ folklore”. Rader points out that semel is a Latin word for once (it’s derived in turn, although Rader doesn’t mention this, from a Proto-IndoEuropean root sem for one). Semelparity (once-bearing), he argues, therefore parallels iteroparity (repeated-bearing).
This etymology is simple and plausible, but I’m not convinced. The term was coined by Lamont Cole, in his 1954 paper on life histories. Cole didn’t explain the reasoning behind his coining, and it’s too late to ask him. But for three reasons, I’m suspicious of the Latin-semel-once story.
(1) Virtually all our other vocabulary uses other Greek or Latin roots to refer to single instances of things: monomorphic, monocarpic, univoltine, unicorn. I’m aware of only one other English word that uses Latin-semel-once: the linguistics term semelfactive, which (Rader says) describes Slavic verbs referring to single occurrences of actions. Why would Cole base a coining on a root that occurs nowhere else in biology?
(2) Counting on readers to recognize semel as Latin “once” risks confusion with the much more common Latin semi “half”, and this seems unwise. But for those who know some Greek mythology (and Cole, well-educated and of my grandparents’ generation, surely did), semel based on Semele is clear.
(3) Semelparity is about a little more than “once”. Yes, semelparous organisms reproduce once; but beyond that: they do so because their reproduction causes death**. Semel as “once” misses that half of the story, while an origin of semel from Semele captures it. If Cole had wanted only to express the notion of a single reproductive bout, existing words such as monocarpic were available.
So we have two rival*** etymologies, and each is plausible. If Cole really meant the Latin semel for “once”, then semelparity seems a disappointingly bad coining – obscure, confusing, and redundant with other perfectly good terms. But if Cole meant the Greek person Semele, the term is evocative and memorable (albeit messy, since then it mixes Greek with the Latin parous “bearing”). It could be that I just want the Semele story to be true – but I see good enough reason to keep my mind open. From now on, I’m going to teach both possible etymologies for semelparity; but I’m willing to bet it will still be Semele’s story that nobody ever forgets.
© Stephen Heard (firstname.lastname@example.org) October 20, 2015
*Nobody ought to be surprised by this. Least of all me. After all, I alert us both to this possibility right in the Scientist Sees Squirrel masthead.
**Usually indirectly, through redirection of resources away from maintenance or defence. But in some cases, reproduction is a direct cause of death – for instance, in certain gall midges (Diptera: Cecidomyiidae), in which eggs hatch and larvae develop inside the haemocoel of the mother, consuming her tissues and emerging by rupturing her body wall. Ouch.
***There may be some middle ground, because the origins of the name Semele are unclear. It’s been claimed to come from Proto-IndoEuropean dgem, meaning earth, by why would it? Origin from Proto-IndoEuropean sem meaning “one” would fit Semele’s story much better. If this is true, then there’s not much daylight between the two etymologies anyway.