Starfish by the starfish in an escape response. The loss of parts of the body is achieved by the rapid softening of a special type of connective tissue in response to nervous signals. This type of tissue is called catch connective tissue and is found in most echinoderms. An autotomy-promoting factor has been identified which, when injected into another starfish, causes rapid shedding of arms. The lifespan of a starfish varies considerably between species, generally being longer in larger forms and in those with planktonic larvae. For example, "Leptasterias hexactis" broods a small number of large-yolked eggs. It has an adult
Starfish in the Virgin Islands appears to regulate the diversity, distribution and abundance of microorganisms. These starfish engulf piles of sediment removing the surface films and algae adhering to the particles. Organisms that dislike this disturbance are replaced by others better able to rapidly recolonise "clean" sediment. In addition, foraging by these migratory starfish creates diverse patches of organic matter, which may play a role in the distribution and abundance of organisms such as fish, crabs and sea urchins that feed on the sediment. Starfish sometimes have negative effects on ecosystems. Outbreaks of crown-of-thorns starfish have caused damage to coral reefs