Figure 1. Pollicipes polymerus is a stalked or gooseneck barnacle. It typically lives in dense clumps permanently attached to the bottom. The body, which is surrounded by a cluster of calcareous plates (white), sits on top of a fleshy stalk (brown) that can sometimes be many times longer than the length of the body. Pollicipes extend feathery feeding legs (cirri, inset) out into the water to capture prey dislodged by breaking waves. They also possess an extensible penis (arrow, inset) that is unusually short for barnacles (only ~0.7 body lengths compared to >2X body lengths for most species).
And you thought online dating was wacky!
This is Sandra Tsing Loh with the Loh Down on Science
Saying, prepare to be impressed. For their body size, these crustaceans have some of the world’s longest male members! Four or more times their body length!
That’s handy, since they live glued to rocks. To mate, scientists have thought that barnacles simply reach over and fertilize their neighbors. Or, if alone, fertilize themselves. They’re hermaphrodites. So they can do that.
But Pacific “gooseneck barnacles” have smaller units. They can’t always reach neighbors. Is, uh, "self-service" their only option?
To find out, biologists from the University of Alberta collected goosenecks. Some were clustered; others were sad, isolated barnacles. All contained fertilized eggs.
When the team analyzed the eggs’ DNA ... surprise! All egg masses from isolated barnacles’ contained DNA other than their own.
So these barnacles must shoot their sperm out into the water, and likewise catch sperm from others doing the same thing.
And if that’s too much information, perhaps it’s time for us to clam up. Yikes.