Females and Males Respond Differently to Urbanization (the Case Study in Ground Beetles)

The study was based on a large database of morphometric measurements of the ground beetle Carabus granulatus. It was compiled between 2006 and 2025 and includes over 10,000 individuals of this species, captured in 14 major regions of Russia and Western Europe. Beetles were captured with Barber traps across a spectrum of anthropogenic impacts—urban areas, suburbs, agricultural lands, and natural biotopes. They were then transported to the Institute of Ecology of the Academy of Sciences of the Republic of Tatarstan, where they were measured using a unified method for six linear traits. SSD was assessed using two methods. Using the standard Lovich formula, SSD for all traits was significantly higher, on average in all six traits, in beetle populations from suburban areas. Application of the second method, RMAII, showed that the slope of the regression curve is generally higher in females, indicating greater sensitivity of Carabus granulatus females to environmental factors. At the same time, a comparison of the results obtained by the aforementioned methods did not support the thesis that SSD increases with beetle size. The curves for SSD variability in both urban and non-urban populations were sawtooth-shaped. This conclusion may be due to the fact that the variability of both structural traits and SSD for them is not described by a monotonic curve. This necessitates studying the variability of SSD in other ground beetle species (or genera) using the same data set and a unified methodology.