Identical treatment groups consisting of light & dark, high & low temperature, high & low food and all combinations thereof were developed for each species in order to contrast the effects in both an obligate metamorph and a facultative paedomorph
Asynarchus survival was lower in the presence of salamander larvae and paedomorphs
than in the presence of metamorphs and in control treatments, which did not differ (one-way ANOVA, Scheffe a posteriori contrast P [less than] 0.
The most problematic, and most challenging, speciation issues in this complex involve the nontransforming paedomorphs
or axolotls from Mexico.
Most of these paedomorphic species belong to the Family Ambystomatidae, and paedomorphic species are either obligatory paedomorphs
or facultative paedomorphs
were chosen for analysis over metamorphs because too few individuals metamorphosed to study.
The other significant factor was developmental status: larval salamanders (both paedomorphs
and juvenile larvae) at different prey than transformed salamanders.
Evolutionary evidence supports this, since cave-dwelling salamanders are obligate paedomorphs
(4), and removal of these salamanders to the lab often stimulates metamorphosis (5).