Editing Symbion (section)

== Reproduction ==
''Symbion'' reproduces both [[asexual reproduction|asexually]] and sexually, and has a complex reproduction cycle, a strategy evolved to produce as many offspring as possible that can survive and find a new host when the lobster they live on sheds its shell. The asexual individuals are the largest ones. The sexual individuals do not eat.

During the autumn they make copies of themselves, where a new individual grows inside the parent body, one offspring at the time. The new offspring attach themselves to an available spot on the lobster, begin to feed and eventually start making new copies of themselves. 

In early winter, the asexual animals start producing males. When a male is born, it crawls away from its parent and glues itself to another asexual individual. Once attached, the male produces two dwarf males inside its body, which turns into a hollow pouch. Each of the two dwarf males are about one hundred times smaller than the asexual individual to which they are attached. Their bodies start out with about 200 cells, but this number has been reduced to just 47 by the time they reach maturity. Thirty-four of the cells form its nervous system, and three more become sensory cells used to help them feel their surroundings. Eight cells becomes mucous glands, which produce mucus that helps them move across the surface. The final two cells form the testes, which make the sperm that fertilize the female's egg. Most of the cells of the dwarf males also lose their nucleus and shrink to almost half their size, which is an adaptation that allows two mature individuals to fit inside the body of the parent male. Two males increases their chances to fertilize a female. 

By late winter, when the large feeding individuals in the colony have males attached to their bodies, they start making females. Each female has a single egg inside her. When she is about to be born, one of the two dwarf males fertilizes her when she comes out. The fertilized female finds herself a place on the host's whiskers where she attaches herself. Inside her the developing embryo extracts all the nutrients it needs to grow from its mother, and by the time it is ready to be born, all that remains of the mother is an empty husk. This new offspring is a strong swimmer unlike all the other forms in the colony, and those who succeed in finding a new host will attach themselves to its mouthparts, where it will grow a stomach and mouthparts, morphing into a large, feeding and asexual type, starting the cycle all over again.<ref>[https://www.sciencenewsforstudents.org/article/living-mysteries-complex-beast-lurks-lobster-whiskers Living Mysteries: This complex beast lurks on lobster whiskers]</ref>
The larval stage may be unscientifically referred to as sea worms.<ref>[[Ross Piper|Piper, Ross]] (2007), ''Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals'', [[Greenwood Press (publisher)|Greenwood Press]].</ref>