Evolutionary bases for trophic ecological shifts in an adaptive radiation event: the case of the red devil spiders from the Canary Islands

• Applicant: Adrià Bellvert, Ph.D.
• Subject Area: Systematics and Morphology (Zoology)
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 568192931

This project focuses on understanding the primary evolutionary factors driving trophic shifts within an adaptive radiation scenario, specifically examining the diversification of Dysdera spiders in the Canary Islands. This group has experienced significant speciation within the archipelago, with different trophic preferences playing a pivotal role. Trophic adaptations have led to the repeated evolution of various cheliceral (the spiders' mouthparts) morphologies, each adapted to different levels of isopod predation. Like other cases of adaptive radiation events, extensive research has been conducted on the phenotypic traits associated with specific ecological roles and their influence on the evolution of the group. However, less attention has been devoted to the biological changes these species have undergone throughout their evolutionary history that contributed to adapting to different ecological regimes. We aim to understand how Dysdera species have adapted to the different trophic preferences that led to their successful diversification in the islands. The goal of this project is to determine whether specific muscles of the chelicerae have a stronger influence on morphological changes or if, on the contrary, a combination of these muscles defines the respective phenotypes. Concurrently, we seek to demonstrate how these modifications manifest in different bite forces and how they correlate with trophic preferences. Finally, initial insights into the venom composition of these species will be provided to uncover their role in trophic shifts. In this context, we want to test whether the observed trophic preferences are solely based on the mechanical ability to overcome defense mechanisms of the preferred prey (woodlice) or if the adaptation of more targeted venom plays a significant role in prey capture. With this project, we will gain a deeper insight into how species evolve under an adaptive radiation event, a process that has contributed significantly to our understanding of species evolution and is one of the main drivers of Earth's biodiversity.

• DFG Programme: Research Grants