The role of dispersal in spider speciation, distribution, and patterns of species richness focusing on long-jawed spiders (Araneae: Tetragnathidae) of the Caribbean archipelagoČandek, Klemen (Avtor) Kuntner, Matjaž (Mentor) Agnarsson, Ingi (Komentor) dispersalbiogeographyspecies richnessphylogenyTetragnathidaeDispersal is an organismal attribute that shapes biodiversity and affects species distributions. Island systems, a limited area with discrete units separated by barriers to gene flow, pose as excellent arenas to study dispersal. Here, we focus on the Caribbean spiders from Tetragnathidae family, but we expand our research wider to all spiders. In four standalone studies we use phylogenetic, biogeographic and machine learning approaches to look for general patterns of interaction among species richness, biogeographic histories, dispersal abilities and among other factors that potentionally influence biodiverstiy. First, we investigate the biogeography of the Caribbean Cyrtognatha spiders (Tetragnathidae). Our results suggest Cyrtognatha colonized the Caribbean by overwater dispersal in mid-Miocene. Moreover, we recover Cyrtognatha as a young clade, containing exclusively single island endemic species of putatively poor dispersal abilities. Second, we reconstruct Caribbean Tetragnatha biogeography in the context of global Tetragnatha (Tetragnathidae) distribution. These results suggest that Tetragnatha repeatedly and independently colonized the Caribbean on multiple occasions. We find Tetragnatha unique among the arachnids explored so far. Tetragnatha comprises some species that are excellent dispersers, and others that are not, perhaps having secondarily lost this dispersal propensity. Tetragnatha thus represent a complex combination of attributes of a ‘dynamic disperser’. In the third study, we investigate a biogeographic imprint of a more conventional excellent disperser, Trichonephila clavipes (Nephilidae), on the Caribbean. The results are consistent with a single species of T. clavipes across the Caribbean that also maintains a lively gene flow with North America. However, T. clavipes from Central and South America likely represent one or even two cryptic species. Finally, we search for the best predictors of species richness of spider genera among 22 variables from their morphological, genetic, geographic, ecological and behavioral landscapes. The results from Random forest and Multiple correspondence analysis suggest that small body size and wide geographic ranges best predict high species richness. However, the most prominent attribute associated with dispersal in spiders - ballooning, holds little predictive power for species richness. By studying and comparing biogeographic patterns of three distinct types of dispersers we provide preliminary support for the intermediate dispersal model (IDM) of biogeography. IDM predicts that taxonomic ranks with species of intermediate dispersal abilities will be the most diverse within the archipelago. However, we note that a priori categorization of dispersal ability is an oversimplification. Dispersal ability of taxa is likely a continuous trait, one which is particularly hard to quantify, and is highly susceptible to changes under evolutionary pressures. While we uncover the effect of dispersal on species richness of Cyrtognatha, Tetragnatha and Trichonephila, we also identify other attributes associated with species richness in 45 diverse spider genera and expose body size as a good predictor of species richness in spiders.20182019-01-10 07:45:02Doktorsko delo/naloga105983VisID: 163271COBISS_ID: 930679sl