I saw this as well. I haven't had a chance to read beyond the abstract, but it's an interesting issue to consider in the context of captive husbandry. Do aposematic dendrobatids require more food, or more frequent feedings, or have more specific food requirements then non-aposematic ones?
In a previous paper (citation below), the authors sort a (pre-Aromobatidae) phylogenetic tree of dendrobatids into conspicuously and inconspicuously-colored species. They also indicate two diet-specialized clades which include the majority of conspicuously-colored species. This recent paper compares the metabolic rate of species in the conspicously-colored, diet-specialized clades to (what I presume are) less derived, more cryptic diet-generalists. Apparently, diet-specialists have "a greater aerobic capacity".
I don't have much experience keeping frogs from outside of the author's aposematic clades. I do keep H. azureiventris (a conspicuously-colored species from a clade of inconspicuous diet-generalists). Anecdotally, I've found them to hold their body weight well on a program of less-frequent and smaller feedings (compared to the other species I keep, which are all in one of the author's conspicuous diet-specialist clades).
Of course, this is anecdote AND speculation. The differences in metabolic rate (which apparently don't include resting rate) between groups of dendrobatids may not even carry over to a captivity. Hopefully someone more knowledgeable on these topics will chime in.
Multiple, Recurring Origins of Aposematism and Diet Specialization in Poison Frogs. Juan Carlos Santos, Luis A. Coloma and David C. Cannatella. PNAS 100 (22): 12792-12797.