Wheel Wearers: Cycliophora

When a lobster seizes its prey, food particles and nutrients are suspended in the water around its mouthparts. The hairlike fibers in the wheel wearer's funnel beat and make a current, which causes water containing food particles to flow into the funnel, where the food particles are grabbed by the hairlike fibers and moved toward the stomach.

Feeding-stage wheel wearers use internal budding to replace their body organs several times. While the organ replacement is going on, the wheel wearers also use internal budding to produce larvae that contain miniature feeding-stage animals. Larvae (LAR-vee) are animals in an early stage that change form before becoming adults. When fully developed, these larvae leave the wheel wearer through the mother's anus (AY-nuhs) Wheel wearers are microscopic animals that live in the mouths of Norway lobsters. (Scanning micrograph by Reinhardt M. Kristensen. Reproduced by permission.) and settle on the lobster's mouth bristles. A bag develops, the larva (LAR-vuh, the singular of larvae) breaks down, and the miniature feeding-stage animal starts to grow inside the bag. After a short time, the funnel emerges through the bag, and the new wheel wearer starts to feed.

Sometimes feeding-stage wheel wearers produce either females or larvae that give rise to males. The male-producing larvae can move only short distances. Immediately after they are released, these larvae seek the closest feeding-stage wheel wearer with a developing female inside and attach to the wheel wearer close to its anal opening. One or two dwarf males then begin to develop inside the larva. When the female leaves through the anus of the wheel wearer, the dwarf males emerge from the larva. Being good swimmers, the dwarf males quickly find and mate with the female, which contains a single large egg. The female then settles on the lobster's mouth. After settling, the female starts to break down and form a bag in which a new larva starts to develop. Larvae in this stage have a dense layer of hairlike fibers on the belly and are much better swimmers than wheel wearers in any of the other stages of the life cycle. They swim to a new lobster or stay free in the water while the lobster is shedding its shell. When the larvae have settled, a bag forms, and a new feeding-stage wheel wearer starts to develop.