title: Tarantulas (Araneae: Theraphosidae) use different adhesive pads complementarily during climbing on smooth surfaces: experimental approach in eight arboreal and burrower species.
abstract: Tarantulas are large spiders with adhesive setae on their legs, which enable them to climb on smooth vertical surfaces. The mechanism proposed to explain adhesion in tarantulas is anisotropic friction, where friction is higher when the leg pushes than when it pulls. However, previous studies and measurements of adhesion in theraphosids were performed using dead specimens. To test their ability to climb, we studied static friction of live theraphosid spiders on different surfaces and at different inclines. We compared burrower with arboreal species to test the hypothesis of higher friction in arboreal tarantulas. We found a complementary participation of claw tufts and scopula of anterior and posterior legs when the tarantula climbs. The mechanics of climbing in association with the biological characteristics of the species are discussed.
authors.affiliation: Sección Entomología, Facultad de Ciencias, Universidad de la República, Iguá 4225, Montevideo 11400, Uruguay myga@fcien.edu.uy.
authors.forename: Fernando
authors.initials: F
authors.lastname: Pérez-Miles
authors.affiliation: Sección Entomología, Facultad de Ciencias, Universidad de la República, Iguá 4225, Montevideo 11400, Uruguay.
authors.forename: Carlos
authors.initials: C
authors.lastname: Perafán
authors.affiliation: Sección Entomología, Facultad de Ciencias, Universidad de la República, Iguá 4225, Montevideo 11400, Uruguay.
authors.forename: Laura
authors.initials: L
authors.lastname: Santamaría
keywords: Claw-tufts; New World tarantula; Tarantula climbing; Tarsal scopula