Sexually dimorphic legs in a neotropical harvestman (Arachnida, Opiliones): Ornament or weapon?

Do sexually dimorphic glands in the harvestman Gryne perlata (Arachnida: Opiliones) release contact pheromones during mating?

“…Considering that this behavior is not involved in pheromone releasing, this behaviour may be tactile in both of these species. Repeated touching of particular parts of the female body with legs or pedipalps during mating is common in harvestmen (Mora, 1990;Willemart et al, 2006Willemart et al, , 2009bNazareth & Machado, 2009;Requena & Machado, 2013; this study, both species), but this is the fi rst time that rubbing is reported. Tapping or rubbing different parts of the body of females may increase the chances of mating success for males at least in some spiders and scorpions (Eberhard, 1996;Huber & Eberhard, 1997;Peretti & Carrera, 2005).…”

Seleção sexual e evolução do dimorfismo sexual em duas espécies de opiliões (Arachnida: Opiliones)

“…Muitas espécies dessa família foram usadas em manipulações experimentais diretamente no campo, permitindo testar hipóteses ecológicas de maneira refinada (e.g., Machado & Oliveira, 1998;2002;Machado et al, 2002Machado et al, , 2005Requena et al, 2009). Outras espécies foram facilmente mantidas em cativeiro, onde executaram comportamentos similares aos observados no campo (e.g., Willemart & Chelini, 2007;Osses et al, 2009;Willemart et al, 2009;Nazareth & Machado, 2010). Dada a enorme variedade de formas de cuidado parental e estratégias de acasalamento nos Gonyleptidae, é provável que a seleção sexual tenha exercido um papel importante na evolução da enorme variedade de formas de dimorfismo sexual na família .…”

“…Much as in the case of the gladiator harvestman Neosadocus maximus (Willemart et al 2009), fighting males turn their backs to each other, but they do not intertwine their fourth pair of legs, probably because the femur IV is long and lacks any spine or tubercle to hook on the legs of the contenders. Once males are back to back, they widely open their forth pair of legs and strike each other using these legs.…”

“…In some species from the Neotropical family Gonyleptidae, males have a strong fourth pair of legs, with several tubercles and spines on the coxa, trochanter, femur, and sometimes on the patella and tibia as well (Kury & Pinto-da-Rocha 2007). Males of the gladiator harvestman Neosadocus maximus (Gonyleptinae), for instance, use their spines and tubercles on femur and coxa IV in male-male fights (Willemart et al 2009). Additionally, all structures directly involved in male-male fights in this species exhibit allometric coefficients significantly higher than nonsexually selected structures, reinforcing the notion that weaponry has evolved under intrasexual selection (Willemart et al 2009).…”

“…Males of the gladiator harvestman Neosadocus maximus (Gonyleptinae), for instance, use their spines and tubercles on femur and coxa IV in male-male fights (Willemart et al 2009). Additionally, all structures directly involved in male-male fights in this species exhibit allometric coefficients significantly higher than nonsexually selected structures, reinforcing the notion that weaponry has evolved under intrasexual selection (Willemart et al 2009). Apparently, N. maximus males fight for the ownership of territories with exclusive access to preferred oviposition sites, and thus to gravid females, much like other harvestmen (e.g.…”