The parental care by the male Common Midwife Toad confers an advantage for survival on the clutch; the males look after the eggs during the early stages of development, thereby avoiding desiccation, freezing, or predation by other organisms.
This feature, which is very advantageous in the natural environment is sometimes inconvenient for captive breeding of the species compared with most amphibians that simply deposit the clutch in the water. Frequently, young males fail to properly roll the clutch up onto their legs and as a result some of the eggs become accidentally detached. Without skin contact of the male, the eggs are no longer protected by the natural skin defences of the male, and eventually die after invasion by fungi from the environment.
Iris Calleja and Julia Catasús, students of the Master of Ecology at the Autonomous University and Complutense University of Madrid, are conducting an experiment to test different techniques which favour the development of the Common Midwife Toad eggs without the presence of the male. In this way, we will increase the number of captive bred specimens that will be released into the wild.
The different treatments tested include the use of different fungicides and ultraviolet radiation, and the eggs are maintained in an environment of high humidity, at a temperature of 20°C.
If we can develop an effective technique to rescue and develop the eggs, not only could we recover the clutches abandoned by young males, but we could increase the production of specimens. Indeed, by removing the eggs from males within a few days of mating, they will continue singing and usually obtain a new clutch from other females.