Mating signal partitioning in multi‐species assemblages: a null model test using frogs

Abstract

Competitive partitioning of ‘community’ signal space has long been suggested to underlie diversification of mating signals. Selection or competitive exclusion is expected to reduce overlap of signals, minimizing destructive interference or reducing mismating. We used null models backed by simulation of type I and II error rates to test for evidence of structuring within 11 frog advertisement call assemblages. Within three assemblages, we found significant over‐dispersion and regularity‐of‐spacing in dominant frequency and in pulse rate, consistent with a signal interference hypothesis and signal confusion hypothesis, respectively. Observed partitioning could represent signal evolution or could result from selection on assemblage composition. Most assemblages showed no acoustic partitioning possibly because: (i) partitioning is more readily apparent in female preference, calling times or sites, rather than call attributes; (ii) assemblages have not yet accommodated recently arrived species, or are compositionally unstable so that acoustic accommodation cannot occur; and (iii) evidence of partitioning is only likely where the acoustic space is densely packed.

Species interactions and the structure of complex communication networks

“…O ne of the core principles of animal communication is that signals should be detectable and convey an accurate message against a noisy background (1-3). This background can involve direct overlap of sounds, as in the case of masking by simultaneous signals (4,5), or simply the co-occurrence of different species using confusingly similar signals at the same location (6)(7)(8). As most animals communicate within assemblages of related species, the problem of signal interference is widespread and may have far-reaching implications for the evolution of signals and signaling behavior.…”

“…This concept-variously termed the "noisy neighbors" hypothesis (9) or "cocktail party problem" (10)-has attracted much attention over recent years. However, the extent to which it provides a general explanation for patterns of signaling in animal communities remains contentious (6,8).…”

Eleutherodactylus frogs show frequency but no temporal partitioning: implications for the acoustic niche hypothesis

“…In 145 a review of 11 assemblages, only 3 showed acoustic partitioning (Chek et al, 2003). However, there was no data 146 on temporal or spatial partitioning in most assemblages and some included data from a large geographical region.…”

“…The study of the spatial dimension will depend on what is known of the behavior of the species. For 175 either of the other two dimensions, acoustic frequency (Chek et al, 2003) or time (Steelman and Dorcas, 2010), 176 may not provide enough data, or the conclusions might not be generalizable due to the unknown influence of the 177 other dimensions.…”

“…All the species of Puerto Rico are closely related (Heinicke et al, 2007;Hedges et al, 2008), most call at the same period of the night, and they are the majority 181 of the anuran fauna in the island. These qualities reduce the added complexity of previous studies that compared 182 communities comprised of several families (Gerhardt and Schwartz, 1995;Chek et al, 2003). Frequency range occupied by each species at each site.…”