How ecological processes such as competition and predation drive the evolution of individual life history traits (e.g., clutch size, age/size at maturity) is well understood. In contrast, how ecological interactions influence the evolution of suites of life history traits (life history syndromes) is much less well-understood. Elucidating how life history syndromes evolve in the face of ecological selective pressures is crucial to explain why certain life history syndromes are prevalent in nature while others are rare or absent. Understanding the coevolution of life history traits that constitute these syndromes is equally crucial in developing a predictive theory for life history evolution as the evolution of one life history trait often alters the selective environment experienced by other life history traits. For instance, the commonly observed phenomenon of larger individuals of a species cannibalizing smaller individuals suggests that evolution in adult body size should frequently affect optimal offspring size.

I investigate the coevolution of life history traits in size-structured consumer populations subject to different ecological selective regimes. Using an individual-based model of a sexually reproducing population, I investigate the long-term evolutionary dynamics of individual life history traits and, ultimately, of life history syndromes. I focused on the interplay between different ecological selection pressures such as density-dependent mortality, resource use, and resource dynamics in driving the evolution of life history syndromes.

Results/Conclusions

Preliminary results show that the broad pattern of a triangular surface in life-history space resembles empirically observed patterns. Coevolution between the size at maturity, reproductive effort, and clutch size emerges across different ecological regimes. This coevolutionary interaction between the size at maturity and clutch size occurs even without any genetic or physiological association between the traits. Moreover, I find that the shape of the size-specific mortality curve, phylogenetic history,  and temporal variability can affect which syndrome a population evolves towards. I will highlight the ecological processes that can give rise to such temporal variability. My results demonstrate how different ecological selective regimes across trophic levels affect the coevolution of life history syndromes across species.