3D reconstruction reveals a long copulatory organ and long sperm storage organ in a pholcid spider with one-palp insertion

IZQUIERDO, MATIAS A; DEDERICHS, TIM M; CARGNELUTTI, FRANCO; MICHALIK, PETER

Montevideo

Congreso; 22 international congress of Arachnology; 2023

International Society of Arachnology

The spiders of the subfamily Ninetinae (Pholcidae) possess characteristics that make them unique. Unlike other species in the family, they are tiny, short-legged spiders that inhabit arid areas of the Americas, Africa, and the Arabian Peninsula. They are the only ones within the family with a synspermia-type sperm transfer system and form the sister group to the rest of the Pholcidae. Beyond ecological data from labels and field observations, the biology of this group is entirely unknown. Here, we present the first data on the reproductive biology of Gertschiola neuquena, a Ninetinae from South America, and analyze the copulatory mechanics to detail the interaction between genital structures. The precopulatory courtship of this species follows the general pattern of the family, but the use of the first pair of legs of the male to grasp the female by the abdomen stands out. During copulation, the male uses only one palp, leaving the other outside, constituting a notable difference from the rest of the family. On the other hand, the genitalia of the female present a "blind sac" type spermatheca, tubular in shape, very long and convoluted. Data on copulatory mechanics reveal that the male's procursus is inserted into the spermatheca during copulation, while the embolus reaches only the first section of it. The relevance of these data to functional theories of sexual selection is discussed.