A04
A04
Life history implications of the mothers’ choice: Niche choice and niche conformance in the fire salamander
Barbara Caspers
Individual niches change over lifetime due to developmental, social or environmental changes. This is especially noticeable in species, in which developmental changes, such as metamorphosis, require the conformation to different niches during ontogeny. The fire salamander (Salamandra salamandra) with its biphasic life cycle, switches its habitat from exclusively aquatic to terrestrial once metamorphosed. In addition to the niche change after metamorphosis, adult female fire salamanders of our study population can choose between two different larval deposition habitats - stream and pond. Population genetic studies have shown that two genetic clusters exist, representing the two habitats. Assortative mating is supposed to be the driving force for the maintenance of the two genetic clusters, with females found at ponds being more likely to mate with genetic pond type males and females found at streams being more likely to mate with stream type males. In early spring and late autumn, females can be seen at the larval deposition habitats. Mating occurs later and is temporary and spatially separated from the time and habitat females use for larval deposition. This provides a unique opportunity to investigate the causes and consequence of niche choice in fire salamanders. The first project will focus on niche conformance in fire salamander larvae. Based on the results of the first funding period, we will use again a classical match-mismatch design, in which larvae deposited into streams will either be transferred into another stream or into ponds and vice versa. This time under completely natural conditions, we aim to investigate (Part A1) whether individual larvae conform to the given niche and whether individuals differ in niche conformance. Furthermore, and again under natural conditions, we will determine the factors influencing metamorphosis and whether differences between individuals of the two larval habitats, and the match and mismatch conditions exist (Part A2). Surprisingly, our first data revealed that larvae transferred into ponds performed better than those transferred into streams, although ponds were expected to be the more stressful larval habitat. Thus, we will investigate chronic stress response of larvae in the two habitats, and test whether larvae of the match conditions experience lower levels of chronic stress than larvae of the mismatch conditions (Part A3). Last, we will investigate whether differences in immunocompetence exist between larvae of the two habitat types (Part A4). In the second project, we will focus on niche choice in fire salamander females, by first investigating the factors that influence the choice for the larval deposition habitat, using a combination of photographic marc recapture analysis and populations genetics (Part B1). Next, we will conduct a battery of personality tests in the adults in our study area to determine potential behavioural differences between individuals of the two types and whether these might influence the choice for a larval deposition habitat or a mate (Part B2). Focusing on fitness relevant traits, such as skin colour pattern, skin microbes and the chemical phenotype we will additionally investigate how the larval habitat affects the adult phenotype and whether these cues influence mate choice (Part B3). Last, this proposal aims to understand the influence on environmental change and therewith rapidly changing weather conditions on niche conformance and niche choice (Part B4). Overall, this project will significantly advance our understanding of causes and consequences of individual niche choice and niche conformance across different life stages.
