The ecological and geographical variability of the morphometric characteristics of Bombus lucorum L. (Hymenoptera: Apidae) bumblebee workers in the North

This study reports the findings of a morphometric analysis conducted on 358 worker specimens of the white-tailed bumblebee, Bombus lucorum , which were collected from the Middle Lena Valley (Central Yakutia) and the Yana River Valley (Central Upper Yana Region, North-Eastern Yakutia). Statistical analyses, including one-way and two-way ANOVA, were employed to evaluate the data. The results indicated that bumblebees from the Central Upper Yana Region exhibited larger body and wing dimensions compared to their counterparts from Central Yakutia; however, significant differences were only noted in the measurements of the notum and abdomen widths (p < 0.01), as well as in all measurements of the front and hind wings (p < 0.001). These changes are posited to have developed as adaptations to more extreme natural and climatic conditions. Furthermore, it was observed that bumblebee workers of B. lucorum collected during the latter part of summer were statistically larger than those gathered earlier in the season. A notable difference was identified between two micropopulations within the Yana River Valley, where bumblebees from a non-transformed biotope were larger than those from a post-fire succession, likely attributable to variations in the availability of trophic resources. In the Middle Lena Valley, the body size of B. lucorum exhibited a significant correlation with forage availability, with larger individuals preferentially utilizing larger plants and inflorescences. Consequently, the sizes and proportions of bumblebee workers of B. lucorum in the North are influenced by a variety of environmental factors, including climatic and biotopic conditions, as well as the availability of trophic resources.