Courtship and mating of Grammostola schulzei, Schmidt 1994 (araneae, theraphosidae) under laboratory conditions.

FERRETTI NELSON; FERRERO ADRIANA

São Pedro, São Paulo, Brasil

Congreso; 17th International Congress of Arachnology; 2007

Universidad de São Paulo e Instituto Butantan

Grammostola schulzei, Schmidt 1994 comprises a medium to large bodied tarantulas. Recently the species was found in Sierra De La Ventana (38º 07’ 63” S 61º 47’ 30” W), Buenos Aires, Argentina; where lives in burrows made always under stones. Five females and four males were collected by hand. In this paper we describe the courtship and mating behaviour based on 11 successful mating. The specimens were kept in glass vial of 13 cm. diameter and were fed with Tenebrio sp. larvae. The encounters were carried out in cages of 30 x 35 and 30 height, videotaped and analyzed with the PC program Video Edit Magic 4.2. All males initiated sexual behavior after contacted female silk. In 77% of cases started with male palpating, which consisted in the two palps moving up and down in an alternating phase hitting the soil, quite different from palpal drumming, in which the perform started at frequency of 3 Hz, and increased sequentially (13 Hz) until it ended. Synchronously with palpal drumming, displayed body vibrations, caused by the movements of legs III. Leg tapping involved only legs I, and consisted in elevating a leg, extended it and lowered rapidly to hit the soil or female’s body. The female displayed a typical behavior of a burrowing tarantula and made rapid bouts of tapping at low amplitude with legs I and palps against the substrate. When the male touched the female, he made spasmodically beats, that involved only legs II and hit her in an alternate or synchronous phase, during clasping and unclasping. After contact, the female raised the carapace and extended the two first pair of legs and also opening fangs. Then the male lunged, clasped her chelicerae and pushed up, raising her to reach a position that form an angle of 60-80º between carapace and abdomen. After clasping, the female entered in a passive state. During clasping only in the 36% of encounters the male displayed smooth slapping over the female’s carapace, made by the metatarsus and tarsus of legs II. Then, he begun a series of palpal insertions attempts in which one palp was lifted into position, fully extended and closed to the female’s genital opening and the other palp was held semi-extended. The number of insertions was 2,73  3,72 per copula. The duration of copulation in seconds was 121,8  179,6. This is the first species of the genus in which females performed sexual response during courtship. Palpating and palpal drumming was considered equal in other studies, but here, consisted in different durations and frequencies. Finally, smooth slapping over the female’s body could be to approach her towards him or help to relax fangs.