Dullahan Incubator

17 September 2013 Comments Off on Dullahan Incubator


Welcome, again, to another semester at Bilkent! As leaves and temperatures start to fall, flocks of fledgling students answer the call of the wild and migrate back to their academic homes, where they will fight for survival against a semester’s worth of courses — and I at last am exempt from this bloody struggle, having done away with my workload. It is a surprisingly liberating feeling, and after a tranquil summer devoted to reading about vampire-werewolf-ravens (I was aware that certain finches had a habit of drinking blood from the feet of seabirds, and that vampires were said to transform into wolves and moths and myriad other things, but this is the first time I’ve seen this exact combination, and it even comes with a charming little fairy tale: a young girl, estranged from her lover, makes a pact with one such raven to reunite with him and agrees to pay the undead bird’s bargain price of her firstborn infant, who she figures would otherwise have died of consumption or something anyway; once the child in question is born, the raven returns to take his prize and promptly sinks his beak into the newborn’s heart, drinking his blood in order to assume his former, human shape — an ending that clearly illustrates what Rumpelstiltskin must have been; the moral of the story is that you probably shouldn’t make deals with demonic ravens, unless you can procure an extra firstborn or two) and listening to Savoy operas, I am finally ready to take on some semblance of a graduate student and actually do a bit of credible research — but before that, I will take the opportunity to ramble on and on about some obscure topic that no one in their right mind should pay any attention to, which incidentally is what this column is all about.

But first I need to choose a topic, and with half of the column already gone on the first paragraph, it had better be a brief one. Luckily for me, tantulocarids seem to perfectly suit the bill.

Combining the best aspects of Sacculina (parasitic barnacles that inject themselves into crabs through their hollow antennae and spread through the unfortunate hosts like barnacle cancer, even rewiring male crabs to look and act more like females in the process) and cycliophorans (tiny commensals that live on the mouthparts of lobsters and have a particularly complex life cycle that involves several different types of larvae successively tearing their way out of each other’s bodies), tantulocarids are a group of rather obscure crustaceans that live as parasites on their larger relatives, and include some of the smallest animals known to man (several species measure less than 100 microns). While parasites generally either live easy lives or die very quickly and miserably, even the lucky tantulocarid hatchling (which at this stage is called a tantulus larva) that successfully clings to a suitable host is faced with a dire conundrum: The sole attachment point of the animal is around its mouth, and if the tantulocarid wants to grow, which in arthropods involves molting, it would have to slither out of its own skin and promptly fall off its host, leaving its hollow exuvia around its hard-earned nesting place. This clearly isn’t in the best interests of the parasite, and might be a reason why many tantulocarids are diminutive (that, and they often parasitize hosts that are themselves tiny).

The larval tantulocarid isn’t helpless, however. Instead of molting, the parasite develops a large sac from its body, and uses it to either incubate eggs that will give rise to a new batch of tantulus larvae (the development of this sac is also associated with the rest of the larval body just up and falling off, which leaves only a tissue-draining head joined to a gigantic, egg-containing sac) or produce a single, undifferentiated mass of cells that will eventually develop into a male or a female (which obtains its nourishment straight from the larva’s digestive tract, having no other access to the host). Mature males and females presumably exit their sacs (in ways that are no doubt quite fatal to their larval “parent”) to mate in open water, producing yet more larvae to repeat the cycle (though the cycle itself is yet to be fully elucidated, and may end up revealing still more surprises).

P.S. It appears that I should be more careful with my column-writing sessions, because I now notice that I have been (terribly) singing along to “La donna è mobile” within earshot of my advisor. I can only hope that I haven’t been heard, though if I have, at least I should consider myself lucky that it wasn’t something more embarrassing, like the sounds accompanying this video of moth claspers that I have on another tab (apparently hawkmoths can pluck specialized scales against their genitalia to produce ultrasound signals that deter pursuing bats — these genital screams may warn the bats that their intended prey is dangerous or unpalatable, or even serve to confuse the bats’ own echolocation systems).