September 19, 2024
Seminar: Anatomy of an adaptive radiation: the red devil spiders of the Canary Islands
Adaptive radiations are a hallmark of island evolution. Oceanic archipelagos, which rise from the ocean floor and have never been connected to mainland areas, provide unparalleled opportunities for accidental colonizers to flourish and diversify. However, identifying the patterns and mechanisms driving species proliferation and ecological adaptation in the context of adaptive radiation is not always straightforward.
To address this, we combined molecular phylogenetic analysis, comparative genomics, geometric morphometry, and experimental testing to investigate the origins and diversification of the red devil spiders (genus Dysdera) in the Canary Islands. This genus comprises approximately 60 endemic species within this volcanic archipelago. Our phylogenomic data support a single origin of these endemic species (with one exception) and suggest that the ancestor colonized the archipelago during the early formation of the present-day islands. The single origin hypothesis is further reinforced by the significant reduction in genome size among island species, primarily due to the loss of repetitive elements.
Trophic specialization has been a key driver of diversification in these endemic species, as evidenced by multiple independent events of onychophagia and accelerated speciation in specialized lineages. Notably, our findings also suggest that the processes of speciation and ecological adaptation are largely independent. The red devil spiders provide one of the most compelling examples of island diversification, and the extensive genomic, morphological, and ecological data available make this system an invaluable model for studying the mechanisms that generate and sustain biodiversity over time.
speaker
Dr. Miquel Arnedo (Institut de Recerca de la Biodiversitat, Universitat de Barcelona)
when and where
19/09/2024
12:00h
Edifici complex M2 (Carrer Blaise Pascal, 7, Parc Bit)
