Evolutionary and Ecological Drivers of Microbial Symbiosis in Host Life History Transitions

Microbial symbionts influence host fitness and developmental trajectories throughout the life cycle, but two factors are particularly critical in determining how these relationships shape, and are reshaped by, host life history: the mode of symbiont transmission (vertical versus horizontal) and environmental change as an external driver of symbiotic reorganization. These two axes are mechanistically linked: transmission mode sets the baseline fidelity and evolutionary stability of a host-symbiont partnership, while environmental perturbation tests and often disrupts that stability, forcing hosts to adjust developmental timing, reproductive investment, or phenotypic plasticity in response.Vertically transmitted symbionts are typically co-inherited with the host genome, favoring tight coevolution and symbiont contributions to conserved developmental programs, whereas horizontally acquired symbionts offer flexibility to respond to changing environments but carry higher uncertainty in partner fidelity across generations. Understanding how these transmission strategies interact with environmental variability, temperature shifts, nutrient stress, habitat disturbance, climate-driven range shifts, to influence host life history plasticity remains a central open question in evolutionary microbiology.This Research Topic focuses on the evolutionary consequences of symbiont transmission strategy and the ecological impact of environmental change on symbiosis-mediated life history plasticity, using host species as supporting evidence for broader mechanistic principles rather than as the organizing framework itself. We welcome studies that use comparative, experimental, or modeling approaches across invertebrates and vertebrates, provided the core focus addresses transmission mode and/or environmental drivers as the mechanistic axis.We invite submissions addressing, but not limited to, the following themes:o Comparative studies of vertical versus horizontal symbiont transmission and their consequences for host developmental timing, reproductive strategy, and offspring fitness.o Evolutionary trade-offs between transmission fidelity and symbiont functional flexibility across host generations.o Environmentally induced reorganization of symbiotic communities (thermal stress, nutrient limitation, habitat disturbance) and downstream effects on host life history plasticity.o Climate change and range-shift scenarios as drivers of symbiont turnover, replacement, or loss, and consequences for host adaptive capacity.o Experimental manipulation of symbiont acquisition mode (transmission blocking, cross-fostering, symbiont swapping) to test causal links to host life history outcomes.o Modeling and theoretical frameworks predicting when transmission mode versus environmental variability dominates as a driver of symbiotic plasticity.o Case studies of symbiosis breakdown (dysbiosis) under environmental stress and its life history fitness costs. Topic editors: Yimeng Li, Xiaolong Hu Source: https://www.frontiersin.org/research-topics/80462/evolutionary-and-ecological-drivers-of-microbial-symbiosis-in-host-life-history-transitions