SFB-TRR 212

Life history implications of the mothers’ choice: Niche choice and niche conformance in the fire salamander (Salamandra salamandra terrestris)

Fire salamander females deposit their larvae into the water, which is either a pond or a first order stream. While females can choose the habitat for larval deposition, larvae have to conform to the habitat they were born in. In the first part, we will focus on the larval perspective, i.e. niche conformance, while in the second part, we will focus on the adult perspective, i.e. niche choice. Based on our observations and the fact that climate change will result in more catastrophic events, we will also put emphasis on the question how environmental change might shape selection pressures and therewith alters niche choice and niche conformance.

Part A - Functions and mechanisms of niche conformance in fire salamander larvae under natural conditions

Using a reciprocal transplant experiment and the established method of photographic identification of individuals based on the tail pattern, we are able to measure larval performance under completely natural conditions, including predation risk. We will investigate:

A1) Niche conformance under natural conditions

A2) Habitat specific differences in the timing of metamorphosis

A3) Quantifying the larval habitat by measuring glucocorticoid release

A4) Habitat specific differences in immunocompetence

This project part will advance our understanding of niche conformance in fire salamander larvae under natural conditions. It will enable us to investigate the importance of predation risk on niche conformance and will advance our understanding on the factors influencing metamorphosis, the impact of the larval habitat and the potential impact of climate change (draught and heavy rainfalls) on this important life history event.

Moreover, this project will advance our understanding of potential selective force shaping the habitat - genotype correlation found in our study site. Understanding the selective forces larvae are faced with, will help us to understand potential strategies how individuals conform to an individual niche and the consequences of the female’s choice of the larval deposition habitat.

Part B – Factors and consequences of niche choice in fire salamander females – mate choice and habitat choice

Using the photographic identifying software Wildbook®, genotyping and field based personality tests we will pursue the following research questions:

B1) Female choice of the larval deposition habitat?

B2) Do adults of the two types differ in their personality traits, and do potential differences influence habitat or mate choice of female fire salamanders?

B3) Is mate choice affected by personality traits, the genotype, or other cues, such as chemical phenotype or skin microbiota?

Overall, this project part will give us in depth knowledge about the fundamental aspects of individual decisions on population divergence, the factors influencing niche choice and the potential consequences for niche conformance in fire salamanders. Furthermore, it will help us not only to understand if and how the larval habitat influences animal personalities across different life stages, but it will also advance our understanding how individual differences in behaviour can be linked to differences in morphology (e.g. colour pattern), spatial distribution, ecology as well as habitat or mate choice. Finally, we will reveal whether and how the larval habitat influences mate choice decisions and will advance our understanding how niche conformance influences niche choice later in life.