Southern Toad
Bd-naïve toads did not avoid of any of the treatments (Treatment:df = 4, χ2 = 2.00, P = 0.736; Fig. 2C).
There was a significant effect of treatment on the avoidance behavior of
Bd-experienced toads (Treatment: df = 4, χ2 =
2.40, P = 0.018, Fig. 2D) but they did not avoid all treatments
equally. Regardless of whether toads were Bd-naïve or Bd-experienced,
toads showed no significant differential avoidance of treatments with or
without zoospores (Zoospores: df = 1, χ2 =
0.11, P = 0.742; Zoospores*experience: df = 1,
χ2 = 0.12, P = 0.729; Fig. 4A) or with or
without live zoospores (Live zoospores: df = 1,
χ2 = 0.03, P = 0.854; Live
zoospores*experience: df = 1, χ2 = 0.33,P = 0.568; Figs. 2D, 4B). However, avoidance of Bd metabolites
was significantly greater when toads were Bd-experienced than Bd-naïve
(Metabolite*experience: df = 1, χ2 = 5.89,P = 0.015; Figs. 4C, 5), suggesting that the metabolites that
contain enzymes that digest amphibian skin trigger a learned avoidance
response. To better estimate the magnitude of learned avoidance of
treatments with metabolites, we compared treatments with metabolites to
only the controls (rather than all treatments without metabolites). In
these analyses, the difference between avoidance when experienced and
naïve was even stronger than in the previous analyses
(Metabolite*experience: df = 1, χ2 = 7.76,P = 0.005). Toad responses to the three treatments containing
metabolites did not differ significantly when naïve or experienced
(Treatment: df = 2, χ2 = 1.06, P =
0.589; Treatment*experience: df = 2, χ2 = 1.69,P = 0.430), indicating that the overall learned avoidance of
metabolites was not a function of just one of these three
metabolites-containing treatments.