Like barnacles clinging and attracting larvae
British scientists have solved the mystery of sessile barnacles: the sessile crustaceans - which include barnacles - likely use the same protein to hold on and attract new larvae.

Barnacles are highly modified crabs that colonize solid substrates such as stones, wood, plants, animals or even ship hulls. Only the larval stages swim freely in the water. Since they mate with each other when reproducing via a penis, the animals have to sit tightly together in large groups. They therefore use a protein complex to attract new larvae that are looking for a suitable substrate for colonization.
The free-swimming larvae, so-called Cypris larvae, do not commit themselves permanently, but can leave the place again. They therefore secrete a protein with which they temporarily stick to the substrate. When the animals separate again, a residue of this adhesive protein remains as a "footprint".
Scientists led by Anthony Clare from the University of Newcastle have now been able to confirm the hypothesis that these footprints attract new larvae: Labeled antibodies against the larval attractant also docked on the tracks of barnacles that had migrated further. This shows that at least part of the attractant is identical to the crayfish's temporary glue.