Reproductive behavior of Chavesincola inexpectabilis (Opiliones, Gonyleptidae) with description of a new and independently evolved case of paternal care in harvestmen

Abstract

In this paper, we investigate the reproductive behavior of the gonyleptid Chavesincola inexpectahilis Soares & Soares 1946 (Heteropachylinae) and provide basic descriptive information about courtship, copulation, oviposition, and paternal care. Like most gonyleptids, males of C. inexpectahilis have a strong armature on the fourth pair of legs and use their spines and apophyses to fight other males and to repel them from their nesting sites. The mating pair interacts briefly before copulation, but the male touches the female both during and after penetration while she oviposits. The oviposition behavior differs markedly from that of other Laniatores: females hold the eggs on the chelicerae before depositing them on the substrate. After oviposition, the eggs are left under the guard of the male to defend against attack from cannibalistic conspecifics. Mapping the available data on reproductive biology of the Gonyleptidae on the phylogeny of the family, it is possible to infer that paternal care has evolved at least three times independently: once in the clade Progonyleptoidellinae + Caelopyginae, once in the Gonyleptinae, and once in the Heteropachylinae, which occupies a basal position within the group.

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).…”

“…Such behaviour could be related to cryptic female choice, which increases the certainty of the paternity of the male (Eberhard, 1996). Finally, unlike in I. pustolosa and C. inexpectabilis, in which females terminated mating (Nazareth & Machado, 2009;Requena & Machado, 2013), both males and females of G. perlata may terminate mating by lowering the prosoma and pulling back.…”

“…Mating posture is similar in all laniatorids studied so far, with both sexes face-to-face and raising the anterior parts of their bodies (Mora, 1990;Machado & Oliveira, 1998;Nazareth & Machado, 2009;Requena & Machado, 2013). However, males of the gonyleptids Acutisoma longipes Roewer, 1913, Chavesincola inexpectabilis Soares & Soares, 1946, and Iporangaia pustulosa Mello-Leitao, 1935 hold the female's pedipalps with their pedipalps (Machado & Oliveira, 1998;Nazareth & Machado, 2009; Requena & Machado, 2013), whereas the males of the cosmetid G. perlata hold the trochanter of the fi rst pair of legs of the females with their pedipalps and those of gonyleptid D. pectinifemur hold females by their trochanter II (Table 1).…”

“…However, males of the gonyleptids Acutisoma longipes Roewer, 1913, Chavesincola inexpectabilis Soares & Soares, 1946, and Iporangaia pustulosa Mello-Leitao, 1935 hold the female's pedipalps with their pedipalps (Machado & Oliveira, 1998;Nazareth & Machado, 2009; Requena & Machado, 2013), whereas the males of the cosmetid G. perlata hold the trochanter of the fi rst pair of legs of the females with their pedipalps and those of gonyleptid D. pectinifemur hold females by their trochanter II (Table 1). It is unknown whether the typical spoon shaped pedipalps of cosmetids (unlike the cylindrical pedipalps of other species) are involved in grasping the opposite sex.…”

“…However, in three cases, males hook and rub trochanter III with tarsus I after they lowered their prosoma, suggesting a post-copulatory courtship. In C. inexpectabilis and I. pustulosa, males also "tapped"/"gently touched" females after mating (Nazareth & Machado, 2009;Requena & Machado, 2013). Such behaviour could be related to cryptic female choice, which increases the certainty of the paternity of the male (Eberhard, 1996).…”