Host performance declined with increased temperature (i)
In this simulated invasion event, where G. vermiculophyllaholobionts were transported to a common garden and disturbed with antibiotics, we found strong differences in host performance between temperature regimes and between ranges. These differences were represented by RGR and a disease symptom that manifested itself as brittleness of the algal thallus. While the RGR was nearly a third lower at 22 °C compared to 15 °C (Figure 2A), the risk to develop thallus brittleness increased 3-fold (Figure 2C). These results are therefore in line with our first hypothesis, which posited that G. vermiculophylla performs better at 15°C compared to 22 °C.