Research & Projects

“No two individuals are exactly the same” — a simple truth that conceals the complex nature of biological diversity. Even when genetically identical organisms are raised under identical, highly controlled conditions, they can still differ in measurable ways. This phenomenon, known as intra-genotypic variability (IGV), challenges traditional assumptions that all phenotypic differences are either genetically determined or environmentally induced.

For decades, IGV was dismissed as stochastic “noise” — variation thought to reduce fitness by moving individuals away from the optimal phenotype. However, new theoretical work suggests IGV may actually enhance adaptation, especially in populations experiencing environmental change. Despite its importance, empirical studies testing these ideas remain scarce.

Objectives

This project seeks to understand whether intra-genotypic variability is adaptive, and if so, under what ecological conditions. Specifically:

Goal 1: Quantify IGV and its relationship to fitness components in Daphnia populations prior to a shift in natural selection.

Goal 2: Estimate the genetic variance–covariance structure underlying IGV.

Goal 3: Determine whether IGV facilitates or constrains adaptation to novel predation regimes.

Goal 4: Experimentally confirm the role of IGV in the evolutionary process through large-scale manipulations.

Environmental conditions experienced by parents can shape the traits of their offspring, sometimes persisting across multiple generations — a phenomenon known as transgenerational plasticity. A well-studied form of this is the anticipatory maternal effect, where mothers adjust offspring traits in ways that may match predicted future environments. While theory strongly predicts that anticipatory maternal effects should be widespread, empirical support remains surprisingly limited.

One possible explanation is that another form of maternal influence, condition-transfer effects, plays a larger role than expected. In this case, parental condition — shaped by past environmental quality — is “transferred” to offspring, influencing their performance without requiring parents to anticipate future conditions. Resource availability is thought to be a key driver determining when condition-transfer or anticipatory effects evolve. Yet, the role of resource variation in shaping maternal effects has received little direct study.

This project leverages the Trinidadian killifish (Anablepsoides hartii) system, which spans environments with and without predators, and includes long-term whole-stream canopy manipulation experiments. These ecological contrasts provide powerful opportunities to test how maternal effects evolve under different resource regimes in the wild.

Objectives

This project tests competing predictions for the evolution of maternal effects by integrating ecological experiments and evolutionary analyses. Specifically, we aim to:

Goal 1: Test whether differences in resource availability, linked to predator presence, drive evolutionary divergence in maternal effects.

Goal 1: Assess whether maternal provisioning strategies influence offspring fitness through common-garden experiments.

Colouration is a central trait in ecology and evolution, shaping predator avoidance, mate attraction, communication, and thermoregulation. Many species—from guppies and butterflies to stinkbugs and crabs—exhibit colour plasticity, the ability to adjust colour in response to changing environments. While this phenomenon is well documented, most studies focus on differences in colour between habitats rather than asking whether the plasticity itself—the reaction norms underlying colour change—evolves across ecological gradients.

The Trinidadian killifish (Anablepsoides hartii) provides a unique opportunity to investigate this question. Populations occur across replicated rivers that differ in predation risk, canopy cover, and light environments, creating natural experiments for testing how colour responses evolve. Predation may increase the value of background matching, while canopy variation alters the visual setting in which colour adjustments occur. By combining field surveys with controlled laboratory exposures to contrasting backgrounds, we examine whether colour plasticity differs systematically across ecological contexts.

Objectives

In order to understand the evolution of colour plasticity in this species we aim to:

Goal 1: Quantify baseline colouration and plasticity across replicated high- and low-predation sites.

Goal 2: Test short-term colour responses to contrasting visual environments under controlled laboratory conditions.

Goal 3: Assess whether patterns of plasticity diverge under a long-term canopy manipulation experiment.