Balyanus sea acorn is a genus of barnacles (a suborder of sea acorns). Adults of this species lead a motionless life, attaching to solid surfaces. Settlement is possible only at the larval stage. Currently, about 60 species belong to this genus.
These marine animals (pictured below) have a calcareous shell that attaches to the substrate. The shell itself consists of 6 plates, four of which form a lid and have the ability to move apart. The crustacean lies at the bottom of this house, sticking out its limbs between open plates. At the same time, he makes energetic rhythmic strokes in order to drive water with food particles inside the house.
The sea acorn is seven centimeters in diameter and 13 centimeters long. The color is usually whitish or grayish with longitudinal stripes of purple or brown.
The sea acorn with its wide sole is attached to any surfaces - shells of mollusks, stones, tree roots, piles of piers, bottoms of ships, as well as to various animals. Below you cansee photos of marine animals that an acorn can attach to. The sticky substance produced by the sea acorn is very stable. It can withstand temperatures up to 200 degrees and is unaffected by alkalis, acids and other solvents.
In turn, soft sponges often settle on large shells of sea acorns, for which the crustacean house is a reliable and solid foundation.
Life cycle of sea acorn
The development of the sea acorn consists of the following phases: egg, larva, adult crustacean. The larvae emerging from the eggs are free-swimming and go through two stages: nauplius and cypris. In cold-water species, the larval stage lasts from 2 weeks to 1 month, and in tropical species - about 3-5 days.
Cypris stage larvae do not feed. For some time they swim, but, once in favorable conditions, they attach to the substrate. Adult crustaceans lead a motionless life.
The sea acorn grows and develops at a fairly rapid pace. In the tropical zone, some species reach sexual maturity within 1-2 weeks after settling. In the colder B altic Sea, this takes about three months. The life expectancy of crustaceans ranges from 1-2 years to 5-7 years or more.
How the sea acorn breeds
Cross-fertilization is carried out between individuals sitting side by side. The sea acorn is a hermaphrodite, meaning each has both male and female sex glands. Near the base of the anterior pair of legs, the oviducts open, from which eggs emerge,which then enter the mantle cavity. The spermatic ducts flow into the tubular male copulatory organ, which straightens out during mating, protrudes outward and enters the mantle cavity of the anterior individual. The sperm it releases fertilizes the eggs. Studies have been carried out, during which it became clear that the sea acorn can breed alone. After fertilization, groups of eggs in the mantle cavity unite into egg-bearing plates and begin crushing.
Cold-loving individuals form eggs in the summer, fertilize them in the winter so that the larvae hatch in the spring. Heat-loving individuals lay eggs several times throughout the year.
