Terrestrial amphibians respond to rapidly changing temperatures with individual plasticity of exploratory behaviour.

Terrestrial ectotherms react to acute changes in environmental temperatures by adjusting their behaviour. Evaluating the adaptive potential of these behavioural adjustments requires information on their repeatability and plasticity. We examined behavioural response (exploration) to acute temperature change in two amphibian taxa, alpine (Ichthyosaura alpestris) and smooth (Lissotriton vulgaris) newts. These responses were investigated at both population and individual levels under multiple thermal contexts (dimensions), represented by the direction and range of changing temperature and rearing thermal regimes. Population-level analyses showed species-specific, non-additive effects of direction and range of temperature change on acute thermal reaction norms for exploration, but explained only a low amount (7-23%) of total variation in exploration. In contrast, within- and among-individual variation in acute thermal reaction norm parameters explained 42-50% of total variation in the examined trait. Although immediate thermal responses varied among individuals (repeatability = 0.07 to 0.53), they were largely shaped by environmental contexts during repeated trials. We conclude that these amphibians respond to acute temperature change through individual plasticity of behavioural traits. A repeated-measures approach under multiple thermal contexts will be needed to identify the selective and plastic potential of behavioural responses used by juvenile newts and perhaps other ectotherm taxa to cope with rapidly changing environmental temperatures.

Underwater sound production varies within not between species in sympatric newts.

Sound production is a widespread phenomenon among animals. Effective sound use for mate or species recognition requires some acoustic differentiation at an individual or species level. Several species of caudate amphibians produce underwater sounds, but information about intra- and interspecific variation in their acoustic production is missing. We examined individual, sex, and species variation in underwater sound production in adults of two sympatric newt taxa, Ichthyosaura alpestris and Lissotriton vulgaris. Individual newts produced simple low- (peak frequency = 7-8 kHz) and mid-high frequency (14-17 kHz) clicks, which greatly overlap between sexes and species. Individual differences explained about 40-50% of total variation in sound parameters. These results provide foundations for further studies on the mechanisms and eco-evolutionary consequences of underwater acoustics in newts.

Histomorphological transformation of the auricular cartilage after carbon dioxide laser-assisted Mustardé otoplasty. An experimental study.

In an experiment on ten rabbits, 8 W carbon dioxide (CO(2)) laser evaporation of the perichondrium, together with one-third to one-half of the thickness of the auricle cartilage, was performed. Subsequently, the auricle was bent in the middle of the vaporized area, the corresponding surfaces of which were then apposed and fixed to each other with mattress sutures. Three months later the auricle specimen was harvested for histopathological evaluation. This revealed that the partially laser-ablated cartilage had grown together in the form of a solid cartilaginous column. The regeneration process, originating from chondroblasts as well as from perichondrium cells, was strongly stimulated by the laser energy delivered.