B02
B02
Niche conformance in a holometabolous invertebrate: Adjustments of behavioural, physiological and chemical phenotypes and fitness consequences
Caroline Müller
Environmental conditions can change dramatically throughout the lifetime of an organism and across generations, leading together with the individual phenotype to specific niches. For example, in insects larval stages are less mobile than adults and thus less free to choose certain conditions. Moreover, larvae and adults often use different diets that influence their phenotypes. Therefore, they need to adjust to their individual niches. However, little is known about the mechanisms mediating such niche conformance and the consequences thereof. In the sawfly Athalia rosae, larvae feed on leaves, while adults feed on nectar. In addition, adults take up clerodanoid compounds from plants, which are known to affect mating and defence against predators. In the first funding period, larval niches were manipulated by offering food ad libitum or exposing larvae to starvation, while adults got either access to clerodanoids or not. Offspring were raised in a match-mismatch design. Starvation in early life had strong intra- but weaker intergenerational effects on key life-history traits such as developmental time, consumption and gene expression. A mismatch between parental and offspring environments had negative consequences on several growth performance traits, highlighting that individual phenotype-environment interactions are crucial. Collection of clerodanoids modified the metabotype of adult individuals and their interactions with conspecifics, but there was little evidence for effects on offspring. In the next funding period, the aims are to explore the mechanisms underlying these adaptations and the consequences on phenotypic trait variation. Next to larvae, adults will be exposed to starvation and effects on life-history, metabolism, behaviour and microbiome will be explored. I hypothesise that adjustments in metabolism and behaviour allow individuals to adapt to food shortage, maintain homeostasis and recover from starvation. These adjustments may depend on the phase at which starvation is experienced, revealing sensitive phases in development. Host starvation regime-specific changes of the microbiota composition may become evident as part of the individualised niche of the sawflies. Adult starvation is predicted to have intergenerational effects on life-history traits. Furthermore, costs and benefits of clerodanoid uptake by the adults will be explored per se and in interaction with starvation. Findings will promote our understanding of factors that shape individualised niche conformance across ontogeny.
