Allometric patterns and phenotypic variation of sexual traits in two sympatric scorpion species with reproductive interference

OVIEDO DIEGO, M.; GIMÉNEZ CARBONARI, J.; SIMIAN, C.; PALEN PIETRI, R.; MATTONI, C. I.; PERETTI, A. V.

Bogotá -virtual

Congreso; I Congreso Latinoamericano de Evolución; 2021

Sociedad Colombiana de Biología Evolutiva, Socevol, Sabe.

Allometric patterns and phenotypicvariation of some traits reveal which selective pressures underlie theirevolution. In sexual traits these patterns may fluctuate according to theirfunctional role as well as other factors such as the  sexual selection intensity (SS). Twoscorpions species (Urophonius spp. - Córdoba, Argentina) withreproductive interference (RI) in a sympatric zone are well suited to explorethe relationship between SS intensity (higher under RI) and allometric andphenotypic variation patterns in sexual traits. For this, we comparedallometric slopes (estimated by major axis regression) and coefficients ofvariation (CV) of male multiple traits (n=119) used in courtship. We predictedisometry for those traits used in courtship and feeding (?mixed traits?:pectines, pedipalps, chelicerae, telson), negative allometry for ?pure traits?used exclusively in courtship for grasp the female pedipalps (pedipalp´apophysis) and positive allometry for the telson gland used for femalestimulation. We found higher CVs for pure traits than for mixed traits. Weobtained isometry for mixed traits in both species, evidencing a balance in theunderlying selective forces (SS and Natural selection). The telson gland wasallometrically positive, with a greater slope in sympatry than in allopatry forone species. Contrary to our prediction, the pedipalp´ apophysis showedpositive allometry. Interestingly, in one of the species, the pectines wereallometrically positive, suggesting that the role of scramble competition couldbe underlying this pattern. We will discuss these results in terms of theasymmetry of SS intensity an IR consequences for these species.