September 22, 2011 — Anyone who has walked in a field or a
roadside has probably at one time or another picked a leaf of a
milkweed plant and observed its milky sap start to flow from the
plant; hence its name. Like all plants, the milkweed contains a
myriad of chemical compounds that are used by the plant in
various ways. Among the compounds produced by the milkweed are
cardiac glycosides; compounds that are toxic to humans and other
vertebrates if eaten. Ingest milkweed and you will probably
experience varied symptoms such as nausea, altered mental
status, and cardiac-related symptoms such as chest pressure and
shortness of breath. If these compounds are so bad, then why is
the milkweed plant a host to a variety of insects? The answer is
that many insects are unaffected by glycosides. These insects
are actually aided by the milkweed’s toxic offering; the
insects’ ingestion of milkweed makes them unpalatable to would-
be predators. Like many other toxic creatures, these insects
advertise their bad taste by br