Dr. Linley Jesson

Research Interests

My research answers ecological and evolutionary questions by integrating experimental, theoretical, and comparative approaches. At present I am interested in three research projects: The evolution of gender dimorphism in plants (both mosses and flowering plants), the fitness costs of local adaptation versus plasticity, and the evolution of reproductive traits.

The evolution and maintenance of combined and separate sexes in moss gametophytes

In collaboration with Phil Garnock-Jones, Sarah Eppley and others

How are separate sexes maintained and why do combined sexes sometimes evolve? Models derived for animals and seed plants suggest that inbreeding and resources influence whether sexes are separate or combined. Mosses have different life cycles and resource allocation patterns from animals and seed plants, allowing us to look at these questions in new ways.

Questions we are addressing include:

  • how often and in which groups did separate and combined sexes evolve in mosses?
  • what are the ecological correlates of breeding system in mosses?
  • is there correlated evolution of selfing and polyploidy in mosses?
  • how does self fertilisation within a gametophyte change predictions from theoretical models derived for other organisms?
  • what are the types and frequency of selfing in moss populations?
  • does selfing purge inbreeding depression in moss species with combined sexes?

  • Local adaptation and the costs of plasticity

    In collaboration with Dave Kubien

  • Phenotypic plasticity is found in many organisms, and is especially predominant in plants. Yet, there must be cost to plasticity in terms of the acquisition, and processing of information. Local adaptation is likely to be variable in stable environments, but this too can be costly if the environment changes over time or if seeds disperse to different environments. We are using Leptospermum scoparium, a species that can acclimate to soil flooding, to examine the fitness costs of plasticity in experimentally stable versus variable environments.

    The evolution and functional significance of enantiostyly

  • In collaboration with Spencer Barrett

  • My Ph.D thesis examined the evolution and functional significance of enantiostyly. Enantiostyly is a phenomenon where the female sex organs are deflected either to the left or to the right of the main axis of the flower. One type of enantiostyly is monomorphic enantiostyly. Here plants have left-styled and right-styled flowers on the same individuals. Another type of enantiostyly is dimorphic enantiostyly. Plants are entirely left or entirely right. We have shown that in Heteranthera multiflora this is controlled by a single gene with right-styled flowers dominant to left-styled flowers.

  • Future projects of interest include:

    • Interactions between haploid and diploid phases in mosses and flowering plants

    • The influence of floral designs on maternal and paternal fitness.

    • The ecophysiology of gender specialisation in mosses and flowering plants