DOI: 10.5061/dryad.ttdz08m3q
title: Genetic diversity varies with species traits and latitude in predatory soil arthropods (Myriapoda: Chilopoda)

description: Aim To investigate the drivers of intra-specific genetic diversity in
 centipedes, a group of ancient predatory soil arthropods. Location Asia,
 Australasia and Europe Time period Present Major taxa studied Centipedes
 (Class: Chilopoda) Methods We assembled a database of 1245 mitochondrial
 cytochrome c oxidase subunit I sequences representing 128 centipede
 species from all five orders of Chilopoda. This sequence dataset was used
 to estimate genetic diversity for centipede species and compare its
 distribution with estimates from other arthropod groups. We studied the
 variation in centipede genetic diversity with species traits and
 biogeography using a beta regression framework, controlling for the effect
 of shared evolutionary history within a family. Results A wide variation
 in genetic diversity across centipede species (0 to 0.1713) falls towards
 the higher end of values among arthropods. Overall, 27.57% of the
 variation in mitochondrial COI genetic diversity in centipedes was
 explained by a combination of predictors related to life history and
 biogeography. Genetic diversity decreased with body size and latitudinal
 position of sampled localities, was greater in species showing maternal
 care and increased with geographic distance among conspecifics. Main
 conclusions Centipedes fall towards the higher end of genetic diversity
 among arthropods, which may be related to their long evolutionary history
 and low dispersal ability. In centipedes, the negative association of body
 size with genetic diversity may be mediated by its influence on local
 abundance or the influence of ecological strategy on long-term population
 history. Species with maternal care had higher genetic diversity, which
 goes against expectations and needs further scrutiny. Hemispheric
 differences in genetic diversity can be due to historic climatic stability
 and lower seasonality in the southern hemisphere. Overall, we find that
 despite the differences in mean genetic diversity among animals, similar
 processes related to life history strategy and biogeography are associated
 with the variation within them.
description: Centipede mitochondrial COI accession numbers were obtained from
 published literature and GenBank sequence datasets. These were
 supplemented with sequences from additional centipede species using the
 <em>phylogatR </em>database (https://phylogatr.org/). Information on geographic coordinates associated with sequences was obtained from source literature and by querying specimen voucher numbers against museum databases. For a small proportion of sequences, coordinates were obtained by geocoding locality descriptions. Information on species traits was obtained from species descriptions in taxonomic studies, and species range was obtained from Chilobase 2.0 (https://chilobase.biologia.unipd.it/), GBIF (https://www.gbif.org/), species descriptions and regional atlases. Species with at least three sequence representatives and complete trait information were retained for analysis. Sequence alignments were carried out for each species and sequence statistics, including genetic diversity, were calculated using R scripts. Important correlates of intra-specific genetic diversity were identified using a beta regression model, where average pairwise difference was the response variable, and, body size, blindness, maternal care, species latitudinal range, mean latitude of sequences, average geographic distance between sequences and number of sequences were the predictor variables. Spatial autocorrelation in model residuals was corrected using additional spatial eigenvectors as predictors, and sensitivity of results to sample size was tested. The analysis described above was carried out using custom R scripts.
description: The analysis code can be run in the R programming language.