I'm new-ish to HubPages, but wonder if perhaps because you have no spaces between names of butterflies and the following parenthesis if the word cannot be found, and thus doesn't rate high in a search feature.
For example, you may have something like monarch(Latin name here), and the word "monarch" won't be found since a search engine would be only seeing "monarch(Latin", which, of course, is not a word.
There are a few other mis-spellings as well. Like I said, I don't wish to criticize, but just have experience on my website w/ getting it found by Google and can see that this small error may be costing you in bigger ways than would seem plausible.
Okay, editing my comments to include this example from your fine Hub--see how there are missing spaces between the plant and the following Latin name? That means that gardeners, for example, who may otherwise find your Hub, won't. From your Butterfly Hub:
Indian Hemp(Apocynum cannabinum), Butterfly Weed(Asclepias tuberosa),Golden Rod(Solidago sp), and Red Clover(Trifolium pratense)