Throughout the Neotropics, temperature and precipitation change with elevation and these changes affect the assemblage of species at any particular elevation. We documented the diversity of litter-inhabiting spiders, (Arachnida: Araneae) along a Costa Rican elevational gradient as it relates to covarying abiotic factors such as temperature and precipitation. The spiders we collected were principally unidentifiable juveniles and so we used Barcode Index Numbers (BINs) derived from DNA barcodes as proxies for species-level interim names. We contrasted these taxon-based estimates with phylogenetic measures of alpha and beta diversity derived from both the mitochondrial DNA barcode region and a multi-gene phylogeny of spiders and found that neither the abundance nor the species-richness of spiders was significantly correlated with elevation, temperature or precipitation. However, we did find that spider assemblages in the upper elevation cloud forests were phylogenetically clustered, (and this pattern was unrelated to whether the phylogenetic patterns were derived mitochondrially or from a multi-gene analysis). One standard explanation for such a pattern is that harsh abiotic conditions in higher elevation forests have selected for particular spider lineages however this remains to be tested fully. The diversity of leaf-litter spider species we uncovered was high and further sampling of spider abundance and diversity across the ACG is likely to yield many new species.

DS-ASSPIDER Collection Data.xlsx - This is the collection and sequence information associated with each of the samples analysed. All specimen information, DNA sequences, and corresponding metadata are available on BOLD and will continue to be updated (dx.doi.org/10.5883/DS-ASSPIDER).

ML_pGH16_by_gene_boot1K_named.nwk - A recent comprehensive spider phylogeny was published comprising more than 700 genera based on six genes (3 nuclear and 3 mitochondrial, including COI) (Wheeler et al. 2017). We used Wheeler et al.’s COI dataset to compare our sequences to make interim generic assignments based on sequence similarity. Using these generic assignments we then calculated genera richness, phylogenetic diversity and community structure as inferred from comparison with the larger multi-gene Wheeler et al. (2017) phylogeny. This is the Wheeler phylogeny used in newick format. 

phylo_barcode_180327.nwk - We constructed a maximum likelihood tree in MEGA6 using one high-quality sequence (greatest length and fewest ambiguities) for each species. This tree was created using a general time reversible model with discrete gamma distribution. Calculations of the best substitution pattern were made in MEGA6 using the “find best DNA model” function. This is that barcode-derived phlogeny in newick format. 

comm_barcode_180327.csv - This is the community matrix of DNA barcode derived OTU's and their occurence along this ACG elevational gradient.  

ML_pGH16_by_gene_boot1K_named_matrix.csv - This is the community matrix of genus identified spiders and their occurence along the ACG elevational gradient. 

Wheeler, W. C., J. A. Coddington, L. M. Crowley, D. Dimitrov, P. A. Goloboff, C. E. Griswold, G. Hormiga, L. Prendini, M. J. Ramírez, P. Sierwald, L. Almeida-silva, F. Alvarez-padilla, M. A. Arnedo, L. R. Benavides Silva, S. P. Benjamin, J. E. Bond, C. J. Grismado, E. Hasan, M. Hedin, M. A. Izquierdo, F. M. Labarque, J. Ledford, L. Lopardo, W. P. Maddison, J. A. Miller, L. N. Piacentini, N. I. Platnick, D. Polotow, D. Silva-dávila, N. Scharff, T. Szűts, D. Ubick, C. J. Vink, H. M. Wood, And J. Zhang. 2017. The spider tree of life: phylogeny of Araneae based on target-gene analyses from an extensive taxon sampling. Cladistics 33: 574–616.