Information on the larval development of the midwife toad alytes obstetricans obstetricans laurenti 1768 in the field

Thiesmeier, B.

Salamandra 28(1): 34-48

1992


ISSN/ISBN: 0036-3375
Accession: 007461532

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Abstract
The larval development of the midwife toad (Alytes o. obstetricans) was studied in the field over 5 seasons of reproduction. If water temperatures in the spawning pond are above 20.degree. C during the summer months, the larvae deposited from May to early July metamorphose in the same year. After a larval period of 9 to 11 weeks, they have an average total length of 61 mm (58-64 mm) and an average mass of 2.08 g (1.67-2.48 g). When average water temperatures are below 20.degree. C, all larvae from the actual reproduction period hibernate. After 11 to 15 months, they metamorphose at an average length of 68 mm (65-71 mm) and at an average mass of 3.16 g (2.46-3.85 g). During winter, development is retarded. The mass of summer and winter larvae of equal length differs significantly: this indicates that hibernating larvae draw on their substance. Further factors possibly affecting the larval development are mentioned. Discussing the variable larval development and parental care, it is suggested that Alytes is a primary colonizer of running waters changing to stagnant waters only during increasing cultivation of the landscape.