Yesterday I explained that the little pygmy squid Idiosepius' glue gland produces two different oozes, and so it must be either a duo-gland or an epoxy gland. (By the way, "duo-gland" is a very scientific term. "Epoxy gland" I just made up; glue scientists will probably look at you weirdly if you use it.)
And then I quoted some data from a paper arguing that it is probably an epoxy gland--that is, the two different oozes mix together to form glue.
A little later in the evening, I picked up Mark Norman's absolutely gorgeous Cephalopods: A World Guide and thumbed through it to see what he had to say about pygmy squids. Lo and behold, there's an entire section on "Glue gland in squids":
The pygmy squids and certain bobtail squids have areas in their skin which contain two special cell types. One set of cells produces sticky mucous, enabling these animals to glue to objects . . . If a predator comes along, however, these animals need to have a way of quickly disconnecting the glue. This is where the second set of special cells come in. They produce concentrated acid which quickly melts the mucous's grip on the skin.I was horrified. It's a duo-gland after all? Did I just lead all my sweet, trusting readers astray?
But before handing in my blog license, I rushed back to Google Scholar, and, to my great relief, I found satisfactory justification for both Norman's assertions and my own. Observe: A comparison of the adhesive organs of pygmy squids and bobtail squids!
This lovely paper by von Byern and colleagues illuminates the crux of the matter: while both pygmy squids and bobtail squids have glue glands, those of the bobtail squid are much better understood.
Bobtail squid says: I am the pygmy squid's equal in adorable stickiness!
[credit: Nick Hobgood]
When Norman was writing his book (which was first published in 2000), no one knew how the glue glands of pygmy squids worked. But they knew that bobtail squids had duo-glands, and so, in summarizing the matter for a lay audience, it wasn't absurd for Norman to assume that pygmy squids did too.
But the paper that spurred my post yesterday is hot off the presses--and even they don't say for certain that pygmy squids have epoxy glands. They just present a handful of data suggesting it.
Gentle readers, you have not been led astray. Rather, you have been treated to a glimpse into the very most recent, cutting-edge research on the glue glands of squid!
It's a good thing I don't have to hand in my blogging license, because I couldn't find it anyway.