From DNA barcodes to ecology: Meta-analysis of central European beetles reveal link with species ecology but also to data pattern and gaps

Abstract

DNA barcoding has been used worldwide to identify biological specimens and to delimit species. It represents a cost-effective, fast, and efficient way to assess biodiversity with help of the public Barcode of Life Database (BOLD) accounting for more than 236,000 animal species and more than 10 million barcode sequences. Here, we performed a meta-analysis of available barcode data of central European Coleoptera to detect intraspecific genetic patterns among ecological groups in relation to geographic distance with the aim to investigate a possible link between infraspecific variation and species ecology. We collected information regarding feeding style, body size, as well as habitat and biotope preferences. Mantel tests and two variants of Procrustes analysis, both involving the Principal Coordinates Neighborhood Matrices (PCNM) approach, were applied on genetic and geographic distance matrices. However, significance levels were too low to further use the outcome for further trait investigation: these were in mean for all ecological guilds only 7.5, 9.4, or 15.6% for PCNM + PCA, NMDS + PCA, and Mantel test, respectively, or at best 28% for a single guild. Our study confirmed that certain ecological traits were associated with higher species diversity and foster stronger genetic differentiation. Results suggest that increased numbers of species, sampling localities, and specimens for a chosen area of interest may give new insights to explore barcode data and species ecology for the scope of conservation on a larger scale. We performed a meta-analysis of available barcode data of central European beetles to detect intraspecific genetic patterns among ecological groups in relation to geographic distance, regarding feeding style, body size, as well as habitat and biotope preferences. Our study confirmed that certain ecological traits were associated with higher species diversity and foster stronger genetic differentiation. However, significance levels were too low to further use the outcome for further trait investigation.

Keywords: Central Europe; Coleoptera; DNA barcoding; GBOL.

FIGURE 1

Map of the sampling sites of specimens considered for this study across the Central Europe.

FIGURE 2

Flow chart illustrating the two alternative analyses to the Mantel test used to detect the intraspecific relationship between genetic distances (COI) and geographical distances (XY) starting from pairwise distance matrices of samples. Left side: PCA method; middle: The NMDS method; it starts with the same matrix and ends with a set of axes representing the DNA distances. Right side: PCNM technique performed on geographic coordinates. The PCNM produced a set of eigenvectors which had been regressed in Procrustes superimposition analysis first against NMDS axis, then against PCA eigenvectors. Finally, we performed a significance test with Protest (Jackson, 1995).

FIGURE 3

Mean intraspecific genetic distances plotted vs a) mean geographic intraspecific distances (in km); (b) number of sampled individuals per species (N_ind); (c) number of sampling sites per species (loc); (d) vs geographic distances (km) for guilds with different feeding styles; (e) vs geographic distances (km) for guilds with different habitat preferences; (f) vs geographic distances (km) for body size classes; (g) vs geographic distances (km) for guilds of biotope preference.

FIGURE 4

Violin plots and bar plots of statistic scores from Mantel, NMDS + PCA, and PCNM + PCA analyses across the different ecological guilds and subcategories, differentiated for species with significant (dark gray) and nonsignificant (light gray) correlation. Habitat preferences: h_b = soil, h_e = eurytop, h_f = rotting matters, h_n = nest, h_p = vegetation, h_t = dead wood, h_v = vegetation; h_w = water; biotope preferences: b_e = eurytopic; b_f = wetlands; b_o = open‐land biotypes; b_w = forests; body size classes: s_xs = extra small; s_s = small; s_m = medium; s_l = large and s_xl = extra‐large; feeding style: f_c = coprophagous; f_e = polyphagous; f_m = mycetophagous; f_n = necrophagous; f_p = phytophagous; f_s = saprophagous; f_x = xylophagous; f_z = zoophagous; geographical distance classes: highest threshold measured in km.