Signal detection and signal recognition are necessary for effective communication and, thus, vulnerable to the selective effects of interference by heterospecific signals. Previously, we showed correlative evidence that the frequency response curve of territorial frogs Allobates femoralis is narrower at places where it co-occurs with the frog Ameerega trivittata, which utters a spectrally overlapping call. Here we (1) conducted manipulative experiments to test the underlying assumption that A. trivittata calls affect the behavioral and reproductive performance of unexperienced A. femoralis males. The addition of A. trivittata calls led to larger territories and lower opportunities for mating and breeding in A. femoralis males. Thus, heterospecific masking reduces breeding opportunities through its effects on territorial but not calling behavior. We also (2) tested at a species-rich acoustic community whether the recognition space of five frog species was shaped in a way that minimizes overlap with the heterospecific signal spaces. The recognition space was modeled from the all-or-none phonotactic reactions of territorial males. Our data supported the initial hypothesis for three out of five species. Both data sets suggest that masking interference may shape the receiver portion of the communication systems without concomitant changes in the call.