ESTIMAS – Escaping in time and space

• Applicant: Dr. Jens Joschinski
• Subject Area: Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions ; Evolution, Anthropology
• Term: from 2017 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 398170603

Natural environments fluctuate in space and time. Phenotypic plasticity helps coping with fluctuation, but requires predictable cues - unpredictable environments require different strategies. In such conditions, the best adapted genotype is not necessarily the one with highest arithmetic mean fitness, but the one that consistently avoids extinction. Many organisms thus spread the risk by investing in a wide range of offspring phenotypes (diversified bet-hedging), which differ for example in dispersal ability or in the timing of overwintering. So far, only few studies incorporated the joint evolution of temporal and spatial bet-hedging, concluding that the two strategies are generally interchangeable. These studies considered, however, only annual species with a single timing decision per year. In multivoltine species temporal and spatial bet-hedging strategies occur on different scales, and it is unknown how the two strategies interact, e.g. when the conditions that define the optimal temporal spread vary spatially.While bet-hedging is the superior strategy in entirely unpredictable environments, predictable environments favor phenotypic plasticity. In only partially predictable environments, selection should favour mixed strategies that make use of unreliable cues. This combination of spatiotemporal bet-hedging and partial predictability remains so far unexplored.I will test how spatiotemporal interactions affect the coexistence of bet-hedging strategies, particularly in the presence of partial predictability. I will use an individual – based model to simulate a multivoltine species, which responds to unpredictable winter arrival by either spreading offspring overwintering time or by producing dispersers. Dispersal ranges from a local scale (within a spatially autocorrelated environment) to long-distance dispersal, in which variance in winter arrival varies locally. I will test how these differences in scales and associated time:space interactions affect the joint evolution of temporal and spatial bet-hedging. I will then add partially predictive cues, which alter mean and variance of timing and dispersal decisions. Lastly, in preparation for a subsequent empirical validation, I will parametrize the model with climate data from throughout Europe to predict temporal and spatial bet hedging strategies in future sampling sites. Taken together, the model and the later empirical validation will provide insight into the co-existence and interaction of spatiotemporal bet-hedging strategies.

• DFG Programme: Research Fellowships
• International Connection: Belgium
• Host: Professor Dr. Dries Bonte