Hannes Schraft

Université du Québec à Montréal
Postdoctoral fellow candidate

Supervisor: Pierre-Olivier Montiglio
Start: 2019-09-01


Predicting the evolution of spider web architecture
Today’s biodiversity is shaped by how organisms have evolved in response to ecological challenges in the past. A central challenge for most animals is to find food while avoiding predators. However, traits that help capture food usually also make animals more vulnerable to their own predators. Animals often fine-tune this balance by adjusting their behaviour to the environment. This ability for behavioural adjustment, though, diminishes the pressure of natural selection and thus limits how fast traits can evolve. Predicting trait evolution, therefore, requires assessing the effects of several challenges simultaneously, while also considering the limits to evolution due to behavioural adjustments. This is one of the central aims of evolutionary ecology today. Black widow spiders build easily measured webs with structural elements that facilitate prey capture, as well as elements that provide protection from predators. I will conduct an integrative analysis of the ecological and evolutionary consequences of web architecture. I will measure the effect of web architecture on hunting success, reproductive success, and survival at different field sites with varying levels of prey abundance and predation. By transferring spiders between different sites and then measuring the webs they build, I will determine how spiders flexibly fine-tune the architecture of their webs to different ecological conditions. Using quantitative genetics, I will establish how web architecture is inherited from one generation to the next, and to what extent it can evolve despite flexible architectural fine-tuning by the spiders. This research program integrates behaviour, evolution, and genetics, and will refine our understanding of how ecological processes shape evolution. In addition, it will develop our knowledge of a venomous animal that is rapidly expanding northwards and into urban areas. Results obtained here will help us predict where in Canada these animals will thrive and why.


evolutionary ecology, Extended phenotypes, Fitness, Heritability, Phenotypic plasticity, quantitative genetics