Mating behaviour, nympho-imaginal development and description of a new Mesabolivar species (Araneae: Pholcidae) from the Brazilian dry forest Author Stefani, Vanessa Author Garcia, Kamila Author Vecchia, Carliane Author Silva, Lígia A. Author Guimarães, Barbara Author Tizo-Pedroso, Everton Author Machado, Ewerton O. Author Brescovit, Antonio D. Author Del-Claro, Kleber text Journal of Natural History 2012 2012-08-13 46 33 - 34 2117 2129 http://dx.doi.org/10.1080/00222933.2012.707243 journal article 10.1080/00222933.2012.707243 1464-5262 5201957 Mesabolivar delclaroi Machado and Brescovit sp. nov. ( Figure 1 ) Types Male holotype from Bosque John Kennedy ( 18 ◦ 38 ′ 59 ′′ S , 48 ◦ 11 ′ 05 ′′ W ), Araguari , Minas Gerais , Brazil , September 2009 , B. Guimarães and V. Stefani col., deposited in IBSP (160720) . Paratypes : one male ( IBSP 160722 ) and one female ( IBSP 160721 ) same data as holotype . Etymology The specific name is a patronym in honour of the ethologist Kleber Del-Claro. Diagnosis Very close to Mesabolivar togatus (Keyserling, 1891) , sharing the procursus curvature, the presence of a proximal protrusion and a flat prolateral apophysis in the chelicerae; and the shallow epigynum pocket (see Huber, 2000 , figs. 851–863 for comparison). The male is distinguished by the discrete size of proximal protrusion on chelicerae; the rounded and not totally flat tip of prolateral cheliceral apophysis ( Figure 1A ); and the distinct tip on the procursus in the palp ( Figure 1D–F ) and presence of a barely visible posterior margin of the epigynum pocket in the female epigynum ( Figure 1H ). Description Male ( Holotype ). Total length 3.8, carapace length 1.3, clypeus 0.4, carapace width 1.5; leg I: 41.3 (10.9+0.6+10.6+19.2+missing), tibia II: 7.5, tibia III: 6.7, tibia IV: 4.8, tibia I L/d: 71. Body very similar to M. togatus . Carapace light brown with a longitudinal dark stripe; sternum reddish-brown. Distinct thoracic groove. Eight eyes on slightly elevated ocular area; distance PME-ALE about 100% of PME diameter. Chelicerae light brown, basal segment with a medial apophysis on the prolateral edge, flat pointed and a pointed proximal apophysis ( Figure 1B ). Palps as in Figure 1 (C). Coxa with distinct retrolateral apophysis ( Figure 1C ). Femur with retrolateral proximal apophysis, rectangular shaped ( Figure 1C ). Procursus light brown, dorsally curved, with dorsal microspinulation ( Figure 1C ). Distinct tip of procursus, with projections and a distal membranous projection ( Figure 1D–F ). Bulb simple, without transparent projection ( Figure 1G ), embolic division long and straight, membranous distally, sclerotized prolateral stripe present ( Figure 1G ). Legs light brown, femora with subdistal dark rings; without modified spines, vertical or curved hairs. Retrolateral trichobothrium on tibia I at 1.5%. Tarsi without serrated ventral spines, tarsus II with approximately 19 pseudo-segments. Oval, greenish-blue abdomen with grouped darker spots. Female ( Paratype , IBSP 160721). Total length 3.6, carapace length 0.9, carapace width 1.3; leg I: 17.3 (7.9+0.5+8.1+11.9+1.4), tibia II: 5.6, tibia III: 3.4, tibia IV: 5.3, tibia I L/d: 54. In general, very similar to male. Epigynum brown, slightly elevated, without projections, with a discrete epigynal pocket, centred ( Figure 1H ). Internal genitalia with two porous plates approximately parallel, connected by a dorsal sclerotized region ( Figure 1I ). Figure 1. Mesabolivar delclaroi sp. nov. (A, B) Male chelicerae, (A) frontal, (B) lateral; (C) male left palp, retrolateral; (D–F) procursus tip, (D) prolateral, (E) dorsal, (F) retrolateral; (G) bulb, prolateral; (H–J) epigynum, (H) ventral, (I) lateral, (J) dorsal. Scale bar 0.5 mm. Variation One male: carapace width 1,4; tibia I: 10.1. Two females: carapace width 1.1–1.4; tibia I: 6.2–9.7. Distribution Known only in the type locality. Other material examined. Brazil , Minas Gerais , Araguari , Bosque John Kennedy ( 18 ◦ 38 ′ 59 ′′ S , 48 ◦ 11 ′ 05 ′′ W ), two females September 2009 , B. Guimarães and V. Stefani col. ( IBSP 160723 , 160724 ) . Courtship and copulation behaviour The courtship and copulation were successful for all 15 experimental couples. The quantification and categorization of the behaviours suggest four distinct steps: courtship, pre-copulation, copulation and post-copulation. Courtship – short and interspersed beats of the first pair of legs of the male on the web were observed, with the cephalothorax always directed to the partner (time in minutes, 7.3 ± 5.4, mean ± SD, n = 15, Figure 2 : step I). Alternated chelicerae movements were also documented. Pre-copulation – consists of the first physical contact between the couple. The male quickly walks towards the female, directing its cephalothorax to the partner’s abdomen (cephalothorax directed to opposite sides), positioning the pedipalps on the female’s abdomen (time in seconds, 1.5 ± 0.3, mean ± 1SD, n = 15, Figure 2 : step II). Copulation – the simultaneous insertion of the genital bulbs in the female genital orifices (time in minutes, 5.1 ± 2.3, mean ± 1SD, n = 15). The bristles located in the genital cimbia rub the female’s abdomen whenever she moves and the male’s chelicerae engage the female genitalia during the copulation ( Figure 2 : step III). The release of the bulbs marks the end of the copulation and the beginning of the last phase: Post-copulation – in this phase, the male walks away and cleans the entire pedipalp ( Figure 2 : step IV). Egg sac production and births After a single mating, females produced the first oviposition in 19.25 ± 4.5 days (mean ± SD) and the second 33.14 ± 4.2 days after the hatching of the first egg sac. The number of eggs in each egg sac of the first oviposition was 42 ± 16.6 (mean ± SD, n = 504 eggs ) whereas in the second oviposition a significantly smaller average was obtained, 23.83 ± 3.76 ( n = 286 eggs , U = 126.5, P = 0.002, Mann–Whitney U -test, Figure 3 ). The average number of births for the first egg sac was 31.5 ± 3.4 (mean ± SD; n = 379 immatures ), whereas for the second oviposition it was 19.25 ± 3.9 ( n = 231 immatures ) significantly smaller than in the first round (Mann–Whitney U -test, U = 143.5, P = 0.001, Table 1 ). Throughout the development a decrease in the number of survivors until adulthood occurred in the two quantified ovipositions. In adulthood, 4.8 ± 1.1 (mean ± 1SD) survivors were obtained in the first oviposition and 3.9 ± 1.5 were obtained in the second; these numbers did not differ significantly ( Table 1 ). The developmental time from birth to adulthood was 130.8 ± 9.6 days (first egg sac, mean ± SD) and 128.61 ± 11.1 days (second egg sac), not differing significantly (Mann–Whitney U -test, U = 6.45, P = 0.142) and each instar possessed its own specific growth interval (time in days, Table 1 ). The average length of the cephalothorax in the first instar was 0.23 ± 0.05 mm (mean ± 1SD, n = 379) and in the second instar it was 0.752 ± 0.05 mm ( n = 201), reaching 1.85 ± 0.14 (first oviposition, mean ± SD, n = 58) and 1.83 ± 0.33 (second oviposition, n = 47) in adulthood. In the last developmental instar the male cephalothorax size was of 2.1 ± 0.2 mm in length (mean ± 1SD, n = 25) and 1.9 ± 0.3 mm ( n = 33) in the female for first oviposition, not differing significantly (Mann–Whitney U -test, U = 21.3, P = 2.52). The sexual proportion indicated a greater number of females when compared with males, 4: 3, so indicating a bias of the sex ratio towards females.