Rate and pattern of diversification of red spiders (Araneae: Dysderidae) in the Canary Islands
Abstract
Studies of adaptive radiation have shed light on our current understanding of evolution. However, previous studies that have investigated how species diversified, how diversification rates changed, and how ecological specialization influenced these processes have found few different results across different taxa and geographies/ecosystems, illustrating how complex this process is. To gain a more complete understanding of species evolution, additional model systems that encompass alternative ecological requirements are needed. Here, we present the results of a study aimed at elucidating the diversification mode and evolutionary drivers of the spider genus Dysdera, endemic to the Canary Islands. These species show remarkable phenotypic diversity in their mouthparts, which is associated with different levels of specialization in isopod predation. We investigated the patterns of diversification in lineages and evaluated the role of trophic level specialization as a driver of species diversification. Furthermore, we used climatic variables, developmental data, and morphological information to elucidate the underlying mode of speciation by joint species distribution models and age-range correlation methods. Our results reveal that academic spiders experienced an initial burst of diversification followed by a slowdown in diversification rates, which is characteristic of adaptive radiation. We also found evidence that trophic morphology shaped diversification, with specialist species exhibiting higher diversification rates. Finally, our analysis suggests that speciation occurred primarily in allopatric habitats, with range expansion followed by secondary sympatry.
Rate and pattern of diversification of red spiders (Araneae: Dysderidae) in the Canary Islands
