The AP of Fowler's toad was taken from the right ear, the rest were taken from left ears. Considering these APs along with those
on the previous page (bufonids, part I), one could conclude that the caudal
patch of the bufonid AP is remarkably plastic. Among the bufonids, hylids, dendrobatids, and microhylids, we found conspicuous variation
not only from species to species, but also, to a lesser extent, from individual to individual within species.
Assuming that the variation is linked to genotype, one would conclude that such variation within
species sets the stage for classical selection. For me, then, the questions were:
(1)What is it that that extra piece (caudal extension) of the caudal patch does for the frog or toad?
(2)What were the selective pressures that sculpted it?
Clues for addressing the first question were provided by some comparative physiological studies by Bob Capranica and
Anne Moffat in the 1970s (caudal-extension function).
The most obvious places to look for answers to the second question are in acoustic macro- and microenvironments and in
anuran vocalizations (discussion). In considering these things, it is prudent to recall that
acoustic senses may be useful for detecting potential dangers (e.g., predators) and potential resources (e.g., prey, running
water, and the like), as well as potential mates or rivals.
