SCORPIONS THAT DON'T BREAK THE RULES? HYPOALOMETRY FOR GENITAL TRAITS AND HYPERALOMETRY FOR GRIPPING TRAITS DURING COURTSHIP

GIMÉNEZ CARBONARI, JULIETA; PERETTI, ALFREDO V.; OVIEDO DIEGO, MARIELA; MATTONI, CAMILO

Montevideo

Congreso; 22nd International Congress of Arachnology; 2023

International Society of Arachnology

The dimorphic traits and their allometric patterns are related to different selective pressures faced by both sexes and to the function of the traits evaluated. For this type of studies, scorpions are a very interesting and little studied model. The aim of this work is to quantitatively analyze sexual dimorphism (SD), and allometric slopes of multiple traits in adult individuals of Timogenes elegans (Bothriuridae). Characters used during sexual interactions (chelae, chelicerae, metasoma, telson), and others used in other contexts (pecten, leg, stridulatory organ), as well as genital traits (genital operculum, hemispermatophore) were considered. For this purpose, the structures of 44 males and 17 females were photographed, and different measurements (length, height, width) were taken with ImageJ software. Statistical and graphical analyses were performed with R, and the allometric slopes of the traits were obtained for each sex. It was observed that most of the somatic traits presented a high degree of SD in favor of males (chelae, pecten, telson, leg, metasoma) except chelicerae, which were wider in females. For both sexes, we found negative allometry in the genitalic structures and leg femur; and positive allometry in the chelae, although for the chelae height steeper slope was observed in males than in females. These results would indicate that genital traits would be responding to stabilizing pressures, while the chelae could be under sexual selection pressures. The results are discussed considering the function of each structure from an evolutionary and sexual selection framework.