Hi Alexandre,

As far as I know when this was first developed by Esch (1988) it referred only to helminths. I think it is still mainly suited only to complex life cycle helminths.

Regards,

Katie

This could also be useful if you can get a copy LINCOLN, R. J., BOXSHALL, G. A. & CLARK, P. F. (1982). A Dictionary of Ecology, Evolution and Systematics. Cambridge: Cambridge University Press.

First, you have to be cautious about how you define ecosystem. If you use the wiki definition, http://en.wikipedia.org/wiki/Ecosystem (see bottom of page) then you can identify several different groups of organisms that move between these disparate systems. Anadromy (in either direction) gives many excellent examples of free-living invertebrates and vertebrates. If you define it as moving between aquatic and terrestrial systems, then scale is important and there will be fewer examples, but many insects certainly do so in freshwater systems (to terrestrial), and terrestrial hermit crabs, even Birgo, may do so in aquatic systems. Some tree snails may do so, too, but I'm not familiar with the different life history adaptations in the gastropods. There's no question that parasites have many adaptations that would allow them to be successful at moving between 'ecosystems.' You could argue that a complex life cycle (i.e., with multiple life history stages or multiple hosts) is needed to overcome the changes in the physical environment.