Call intercalation in dyadic interactions in natural choruses of Johnstone’s whistling frog Eleutherodactylus johnstonei (Anura: Eleutherodactylidae)

Assessing acoustic competition between sibling frog species using rhythm analysis

“…As the wallum sedgefrog and the eastern sedgefrog call at a similar frequency (pitch), and have significant overlap in their breeding seasons and calling periods (typically in the evenings after periods of rain/habitat inundation; Lemckert et al, 2013;Lowe et al, 2015Lowe et al, , 2016, there is a high potential for acoustic interference and therefore competition. This interference can impair female mate choice including recognition, detection, localization, and discrimination of calls (Tárano & Carballo, 2016). Therefore, changes in the calling behavior of one or both species would be expected, to indicate that a response to acoustic interference was occurring.…”

“…Both species are likely increasing their calls' beat frequency in response to the presence of their competitor in order to ensure a sufficient number of calls are being made in the gaps of the competitor's calls for signal reception and location to occur (i.e., to avoid signal masking or confusion). They may also be attempting to flood the acoustic space to actively suppress the calls of the competitor species, thereby dominating the acoustic space to ensure signal reception without the risk of overlap degrading the features of the call (Tárano & Carballo, 2016; also see Tobias et al, 2004;Wong et al, 2009 for examples of call suppression in anurans). It is possible that both strategies are being employed by either one of the species as an action and response effect, although no evidence of signal suppression was visible in either the wallum sedgefrog or the eastern sedgefrog.…”

“…Overlapping signaling from individuals of one or more species can degrade the features of the calls and therefore impair various factors of female mate choice including recognition, detection, localization, and discrimination (Tárano & Carballo, 2016). As a result, in several frog species females show a preference for nonoverlapping calls when available (e.g., Bosch & Márquez, 2001;Schwartz et al, 2001).…”

“…As a result, in several frog species females show a preference for nonoverlapping calls when available (e.g., Bosch & Márquez, 2001;Schwartz et al, 2001). Therefore, it is mutually beneficial for sexually active males to adjust the timing of their calls to avoid overlap, specifically via call alternation (Tárano & Carballo, 2016). For example, in a study on Dryophytes avivoca it was found that the females of the species preferred long calls without overlap when offered various two-call choice experiments (Martínez-Rivera & Gerhardt, 2008).…”

The progression pattern of male hyrax songs and the role of climactic ending

“…In a similar manner, the gradual increase in hyrax song amplitude may attract listeners and maintain their attention. In other systems, higher amplitude signals have been found to draw more attention 30 and to be robust to habituation or withdrawal response 31 . For example, male mice ( Mus muscus ) perform an ultrasonic loud, modulated, and syntactically complex “calling song” when they are exposed to the scent of a female, in order to attract her closer.…”