I'm glad you brought this these ideas up Dr. Braem as they reinforce topics I've brought up in several other identification threads. I would agree that pollinator studies are difficult (and very expensive to conduct in foreign countries), but they are not impossible. And yes you can have more than 1 pollinator. I have a very good paper by Hans Banziger (2005) that identified the pollinators of Cyp. guttatum, and how these same pollinators could not pollinate C. flavum and C. yunannanense even though they would enter the flowers of these sympatric species. Whether by pollinator study or metrics based, the question of "how much or many" still ends up in the forefront, and keeps pushing for a statistical solution. I know that some taxonomists have tried cranking ANOVA based statistics on large data bases of either structural or genetic metrics to look for "statistically significant" differences between species. I work in environmental toxicology and live with similar debates every day as to how big an effect is a "real" effect or impact. You end up with a lot of different answers (often depending on who puts the most $$ in the argument). But there is a general convergence on a 20%-25% percent effect as being a "biologically real" effect. This works for things that can be measured but how can you quantify a metric like color?