Amphibians: Play recordings of breeding calls to simulate breeding season in the wild
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 2
Background information and definitions
Calling activity by males is usually prominent in the breeding season and plays an important part in mate selection. Playback of recorded breeding calls may stimulate breeding by increasing competition between males.
Supporting evidence from individual studies
A replicated, before-and-after study in 1994–1996 of roseate frogs Geocrinia rosea at Melbourne Zoo, Australia found that fertile eggs were only laid after recorded mating calls were played, sex ratios were manipulated, females carrying eggs were introduced to males, and frogs had been moved to an indoor enclosure which allowed temporary flooding and had a mix of organic substrates. The only fertile spawning occurred in spring 1996, which contained 25 eggs, but they were destroyed by fungus. From 1994-1995 , two male and three sub-adult frogs were housed in two outdoor tanks (120 x 60 x 60 cm) with a sub-surface water depth 50-100 mm. Males called when they were in outdoor enclosures, but fertile eggs were not produced until animals were moved to indoor tanks. From 1996, 6–7 frogs were housed in each of the five indoor enclosures.Study and other actions tested
A before-and-after study in 2006–2012 in Victoria and New South Wales, Australia found that husbandry interventions such as providing playing recorded mating calls, separating sexes during the non-breeding period, along allowing females to gain significant weight before the breeding period, and providing mate choice for females increased clutch size and decreased egg mortality in captive southern corroboree frogs Pseudophryne corroboree, although no statistical tests were carried out. At Melbourne Zoo from 2006–2009 no recorded mating calls were played, (average clutch size: 17; egg mortality: 91%). A recorded tape of mating calls was installed and played in 2010 (average clutch size: 20; egg mortality: 78%), 2011 (average clutch size: 40; egg mortality: 70%) and in 2012 (average clutch size: 46; egg mortality: 27%). At Taronga Zoo a recorded tape of mating calls was installed and played in 2010 (average clutch size: 80; egg mortality: 72%). In 2011, recorded mating calls were not used (average clutch size: 70; egg mortality: 25.5%). In 2012, recorded mating calls were played (average clutch size: 54; egg mortality: 28%). The tape was played for 15 minutes of each hour from 1800 to 2200 hours and was audible to the frogs in all tanks.Study and other actions tested