Courtship and mating behavior of Grammostola schulzei

Grammostola schulzei (Schmidt 1994) comprises a medium-bodied tarantula. Recently the species was found in Sierra de la Ventana, Buenos Aires, Argentina, where it lives in burrows always made under stones in rocky hills. Our objective was to offer a detailed description of courtship and mating, heretofore unknown, and to determine, under laboratory conditions, where copulation takes place: in the open field as proposed for all species of Grammostola, or at the entrance of the burrow. We carried out two series of experiments, completing 40 trials (20 in open arenas and 20 in burrowing arenas). All males initiated sexual behavior after contact with female silk. Courtship involved palpation, palpal drumming, body vibrations, and leg tapping. Palpation and palpal drumming appeared to operate in different ways. Females displayed typical behavior of a burrowing tarantula, making rapid bouts of tapping vigorously with the first pair of legs and palps. The mating position observed was typical of mygalomorphs, in which the female raises her body up and opens her fangs, the male uses the tibial apophyses to clasp the female's fangs, and finally begins a series of attempts at palpal insertion. The smooth slapping during clasping may serve to keep the female passive and relaxed. The dorsal flexion observed during mating and the number of successful matings in open arenas suggests that copulation would take place outside the burrow. We observed sexual cannibalism during the interactions but in these cases, we registered no previous courtships by the males.