For more information on monarch butterfly waystations try www.MonarchWatch.org.  During the show it was noted that many caterpillars will only feed on specific host-plants.  This is classified in ecology as a stenotypic species (a species with a narrow tolerance in regards to some ecological factor).  Bogs, which have low primary productivity, are known as oligotophic systems.  Mesotrophic and eutrophic are aquatic systems that have intermediate and high primary productivity respectively.  Suggested readings: “Chasing Monarchs” by R.M. Pyle, published by Houghton and Mifflin 1999; “Wetlands” by W.J. Mitsch and J.G. Gosselink, published by Van Nostrand Reinhold, New York, 1993.