Intraspecific Call Variation in the Mimic Poison Frog Ranitomeya imitator

摘要

Calls are important premating isolating barriers in frogs; therefore, studying intraspecific variation in calls might allow the assessment of patterns of call divergence during the early stages of speciation. Ranitomeya imitator, a species of dart-poison frog (Dendrobatidae), has undergone extensive color-pattern diversification through a Mullerian mimetic radiation, establishing four distinct morphs in north-central Peru (striped, banded, varadero, and spotted). Partial reproductive isolation exists between certain color morphs, although the specific mechanisms responsible for this isolation are poorly understood. We conducted a species-wide analysis of variation in advertisement calls to investigate whether distinct mimetic morphs show advertisement call differences. We found that different color morphs generally show weak or no differences in advertisement calls, with two exceptions. First, call pulse rates differed between the striped and banded morphs, and that difference coincides geographically with the mimetic transition zone. Second, there is a difference in both note length and dominant frequency between the striped and varadero morphs, which is also geographically coincident with the mimetic transition zone. Future work in this system should attempt to measure the relative importance of different mating cues ( color-pattern, body size, and advertisement calls) mediating mate choice in this species.