DEVELOPMENTAL INSTABILITY OF SPERMATOPHORE PRODUCTION IN SCORPIONS

OLIVERO, PAOLA A.; OVIEDO DIEGO, MARIELA; VRECH, DAVID E.; PERETTI, ALFREDO V.

Montevideo

Congreso; 22nd International Congress of Arachnology; 2023

International Society of Arachnology

In scorpions, sperm transfer is indirect through a sclerotized spermatophore, which is formedby the union of two hemispermatophores generated in the paraxial organs of the male. Theproduction of hemispermatophores is costly, involving an added expense to the production ofspermatozoa and ejaculate. This energy expenditure over successive matings can generatedevelopmental instability, which can be measured by assessing the deposited spermatophore'sfluctuating asymmetry (FA). More asymmetric spermatophores could be related to failuresduring sperm transfer due to mechanical uncoupling with females. In this context, we analyzedthe FA of spermatophores used in three successive matings in the promiscuous scorpionBothriurus bonariensis (Bothriuridae). In this species, the number of spermatozoa and ejaculatevolume show variation across different matings. We expect that the energetic expenditure inthe production of spermatophores also generates an increasing FA of spermatophores towardsthe last mating. A total of 16 males were exposed to different females every ten days, allowingcourtship and spermatophore deposition; this was repeated until three spermatophores per malewere obtained. In each spermatophore, the FA level of structures important in sperm transferwas measured, and these levels were compared in the three successive spermatophores. Wewill analyze the results in the context of sexual selection. We will compare our data withprevious work to assess whether energy expenditure occurs in different morpho-physiologicalfactors synergistically or antagonistically.