Urbanisation Does Not Affect Allometric Relationships in a Widespread Amazonian Dung Beetle Species

Abstract

The environmental pressures promoted by urban ecosystems can play a pivotal role in the sexual attributes of native species that persist in cities. Dung beetles' body size and cephalic appendages are determinant for mating success and couple acceptance, directly affecting individual fitness. The objective of this study was to test how different levels of urbanisation affect tubercle length–body size allometry of Dichotomius boreus individuals. Dung beetles were sampled in three habitats: city core, city outskirts and rural sites. Individuals had their body and tubercle lengths measured to assess their allometric relationships. There was a hyperallometric relationship between body size and tubercle length, which did not differ between sexes according to their habitat type. Moreover, there were no differences in allometric slopes between habitats in neither sex. The results of our study could suggest that the sexual selective force for the expression of different tubercle lengths in males and females is similar and responded similarly in the different studied habitats of the urban landscape of this study. Future studies encompassing Dichotomius dung beetles would be necessary to establish the evolution of allometric relationships in this clade and its relation to the intra- and interspecific interactions.