A review of leg ornamentation in male wolf spiders, with the description of a new species from Australia, Artoria Schizocoides (Araneae, Lycosidae).
Keywords: Courtship display, sexual dimorphism, sexual selection, secondary sexual traits
Two main evolutionary processes that work independently or in combination are thought to explain sexual dimorphism or the morphological differences between males and females. One category relates morphological differences between males and females to a reduction in intersexual competition for resources (ecological niche partitioning) (Shine 1989; Fairbairn 1997). The second explains sexual dimorphism by differences between the sexes in the relationship between a particular trait and reproductive fitness (sexual selection or differences in reproductive roles) (e.g., Selander 1972; Hedrick & Temeles 1989; Reynolds & Harvey 1994). Sexual selection arises through competition between members of one sex for reproduction with the other sex. Here, dimorphic structures may either be used in direct aggressive encounters with members of the same sex (generally males; intrasexual selection), or used by members of the opposite sex to assess mate quality (generally females; intersexual selection) (Darwin 1871; Andersson 1994).
In wolf spiders, sexual dimorphism is evident in a multitude of forms and most differences between males and females are attributed to differences in reproductive roles. With a few exceptions (e.g., Donacosa merlini Alderweireldt & Jocque 1991) females are larger than males. In most ground dwelling species, these size differences are mainly explained by a fecundity advantage of larger females (Prenter et al. 1997, 1998, 1999). Sexual dimorphism also exists with respect to differences in trophic morphology (i.e., the sizes of che90 licerae and venom glands); these differences have been ascribed to the increased importance of foraging for females rather than an avoidance of intersexual competition for food (Walker & Rypstra 2001, 2002). Across many wolf spider species, especially those with sedentary females, males also possess comparatively longer legs than females. This leg dimorphism is thought to have evolved through an advantage of more mobile males to encounter females occupying permanent burrows (Framenau 2005a). While the above forms of dimorphism refer mainly to differences in body shape or size, dimorphic color patterns to augment body size and condition have also been argued to play an important role in the mating behavior of wolf spiders (Moya-Larano et al. 2003).
Dimorphic patterns of foreleg pigmentation appear to be one of the most widespread and conspicuous form of sexual dimorphism among wolf spiders (Framenau, pers. obs.) and these differences in foreleg ornamentation appear to be driven mostly by sexual selection. Male foreleg ornamentation commonly involves extremely dark pigmentation or very distinct light coloration on individual foreleg segments or covering the entire front pair of legs. In some species, males possess an exaggerated form of foreleg ornamentation involving morphological modifications of the first pair of legs. These morphological modifications occur in a variety of forms in most currently recognized subfamilies of wolf spiders. Our study aims to review the evidence for sexual foreleg dimorphism within the spider family Lycosidae by compiling morphological information from the taxonomic literature. In addition, we describe a species with a novel form of male tibial ornamentation--ventral spatulate modified setae. This species, Artoria schizocoides n. sp., belongs to the Australasian/Pacific subfamily Artoriinae and is the only species within this subfamily known to the authors with excessive setation on the first pair of legs.
MORPHOLOGICAL MODIFICATIONS IN THE FIRST LEG OF WOLF SPIDERS
Morphological modifications of the first pair of legs in male wolf spiders belong to three major categories: (1) elongation, (2) swelling and (3) exaggerated setation, the latter two of which are most prevalent on the tibial segment (Table 1).
Elongation.--An elongation of the front pair of legs can be either subtle (e.g., Alopecosa cuneata (Clerck 1757) (Kronestedt 1990) or very conspicuous (e.g., Artoria flavimana Simon 1909) (Framenau 2002). For example, in the Palaearctic Alopecosa cuneata, the ratio of the length of tibia I to tibia IV is higher than in a related species of similar size, A. pulverulenta (Clerck 1758) (Kronestedt 1990). This elongation of the forelegs has been related to male courtship displays (Kronestedt 1990), as there is direct contact between the forelegs of a male and female A. cuneata in the form of the female grasping the swollen tibial segment of the male with her chelicerae (Kronestedt 1990, for more detail see below). Male Alopecosa taeniata (C. L. Koch 1835) also have longer legs as compared to the closely related A. aculeata (Clerck 1758) (Kronestedt 1990). In this case however, the elongation is not restricted to the forelegs and increased species-specific mobility of males during courtship is suggested to explain this pattern (Kronestedt 1990), although there is currently no experimental evidence to support this hypothesis.
In almost all wolf spiders the fourth pair of legs is the longest, followed by leg I, and then II and III, or less commonly III and II (expressed in the "leg formula": IV > I > II > III or IV > I > III > II). However, in males of the Australian A. flavimana mentioned above, the front pair of legs is extremely elongated and much longer than the fourth pair of legs. In females of A. flavimana the fourth leg is the longest, similar to both sexes of all other species in this genus (Framenau 2002, 2004, 2005b, also this study). The elongation is not restricted to a single segment as in A. cuneata but concerns all segments. The behavioral mating sequence of A. flavimana is not known and therefore the function of this morphological modification remains unclear. In male orb-weaving spiders, an elongation of the first pair of legs has been argued to be beneficial to avoid sexual cannibalism (Elgar et al. 1990).
Swelling.--The tibia of the first leg of male A. cuneata is not only elongated (see above) but also distinctly swollen (Fig. 1). The swollen segment does not appear to purely serve to exaggerate a visual signal during male courtship since the cuticle around the tibia is equipped with numerous pores (Kronestedt 1986, 1990; Dahlem et al. 1987). The pores correspond to exocrine glandular units which are composed of a large adenocyte, a long sinuous epicuticular ductile and a canal cell among supporting epidermal cells (Juberthie-Jupeau et al. 1990). During courtship, the female has to actively grasp one tibia of the male with her chelicerae before he can mount her. During this grasping it is possible that females are able to assess secretions from the male's gland tissue (Dahlem et al. 1987). A swelling of the tibia of the first leg is also evident in Pirata cantralli Wallace & Exline 1978 and Pardosa vancouveri Emerton 1917 (Dondale & Redner 1990), and described as "slight" for A. pulverulenta (see Dahlem et al. 1987), suggesting a similar morphology and function (Table 1). Scattered pores have also been found on legs of other lycosids, e.g., in Pardosa C. L. Koch 1847, Trochosa C. L. Koch 1847 (Kronestedt 1986), and Acantholycosa Dahl 1908 (Kronestedt & Marusik 2002) and in Xerolycosa miniata (C. L. Koch 1834) (Juberthie-Jupeau et al. 1990).
Color dimorphism and excessive setation ("brushes").--The most conspicuous sexual dimorphism in wolf spiders involves differences in foreleg pigmentation between the sexes, with males possessing dark pigmentation on particular foreleg segments. In some species this pigmentation is accompanied by the addition of dense brushes of specialized setae. Male pigmentation/brushes are often referred to as secondary sexual ornamentation and are thought to play an important role in reproductive behavior. The function of male foreleg ornamentation has received a great deal of attention within the Nearctic species of the genus Schizocosa where 14 of the 24 described species in North America display foreleg dimorphisms (Stratton 2005). The dimorphisms of some species are considered "slight" (Stratton 2005) and original species descriptions state that the "general structure and color" of females is "essentially as in males" (S. floridana Bryant 1934, S. maxima Dondale & Redner 1978, S. saltatrix (Hentz 1844)). Without considering these species, four North American species remain that possess foreleg pigmentation only: one species with pigmentation on the tibia (S. uetzi Stratton 1997) and three species with pigmentation on the femur (S. cespitum Dondale & Redner 1978, S. communis (Emerton 1885), S. retrorsa (Banks 1911)) (Stratton 2005). Seven North American species are described as having brushes on their foreleg tibia: four species with tibia I brushes and pigmentation (S. aulonia Dondale 1969, S. bilineata (Emerton 1885), S. salsa Barnes 1953, S. segregata Gertsch & Wallace 1937; Table 1) and three species complexes with tibia I brushes and pigmentation in addition to femur I pigmentation (S. crassipes (Walckenaer 1837) (Fig. 2), S. ocreata (Hentz 1844), S. stridulans (Stratton 1984; Table 1) (Stratton 2005). Based upon a morphological phylogeny of the North American species, male foreleg ornamentation is suggested to have evolved independently five to six times and to have been subsequently lost two or three times (Stratton 2005).
All known Schizocosa species possess a seismic component to their courtship display and seismic signaling is believed to be ancestral in this genus (Stratton 2005). A survey across wolf spiders found male foreleg ornamentation to be associated with the presence of active leg-waving displays, resulting in the suggestion that all ornamented species possess multimodal courtship signaling (seismic and visual) (Hebets & Uetz 2000). In signal isolation experiments across numerous Schizocosa species, which vary in presence or absence and type of foreleg ornamentation, females of only brush-legged species responded to isolated conspecific visual signals while females from all species responded strongly to conspecific male seismic signals (three monomorphic species: S. duplex Chamberlin 1925 (Hebets & Uetz 1999); S. rovneri Uetz & Dondale 1979 (Scheffer et al. 1996); S. saltatrix (Uetz & Roberts 2002); one pigmentation only species: S. uetzi (Hebets & Uetz 1999); and three brush-legged species: S. crassipes, S. stridulans (Hebets & Uetz 1999), and S. ocreata (Scheffer et al. 1996); summarized in Uetz & Roberts 2002; Hebets & Papaj 2005). These results suggest that while seismic signaling is important across all species, visual signaling is putatively important in species with strong sexual foreleg dimorphism.
The foreleg brushes in S. ocreata are known to be condition-dependent (Uetz et al. 2002) and in the absence of seismic signals, females have decreased receptivity to males with shaved versus intact brushes (Scheffer et al. 1996) as well as to males with smaller brushes (McClintock & Uetz 1996). Curiously, female receptivity did not vary with male ornamentation in experiments using the video playback technique, with courtship sequences involving manipulated male ornamentation ("control" video vs "no ornamentation" video vs "enhanced brushes" video; McClintock & Uetz 1996). Live trials involving males with shaved brushes versus intact brushes also did not result in mating frequency differences (Scheffer et al. 1996). Ultimately, tibia I brushes in S. ocreata are thought to increase courtship signal efficacy in a seismically unpredictable, heterogeneous signaling environment (Scheffer et al. 1996). A pre-existing bias in females for foreleg brushes was previously suggested to have played a role in the evolution of S. ocreata foreleg ornamentation (McClintock & Uetz 1996); however a recent morphological phylogeny suggests that the formerly observed preference of females from a non-ornamented species (S. rovneri, McClintock & Uetz (1996)) for males with brushes is a retained behavioral trait (Stratton 2005).
[FIGURES 1-4 OMITTED]
In experiments using the video playback technique in the absence of seismic signals, females of a second brush-legged species, S. crassipes showed a marginally significant preference for pigmented males over non-ornamented males (Hebets & Uetz 2000), suggesting a role of brushes in female mate choice. Females of a third brush-legged species, S. stridulans, were significantly more receptive to video playbacks of males with enhanced brushes as compared to males with pigmentation removed (Hebets & Uetz 2000), clearly demonstrating a role of foreleg ornamentation in female mate choice. However, in a follow-up study using the same video playbacks in conjunction with seismic courtship signals from live males, female S. stridulans did not distinguish among visual stimuli (Hebets unpublished data), suggesting that visual signals are important only in the absence of seismic information for S. stridulans. Interestingly, the exact opposite pattern was observed in a pigmentation only species (S. uetzi), where females did not distinguish among visual stimuli using video playbacks in the absence of a seismic signal (Hebets & Uetz 2000). However, with the addition of a con-specific seismic signal, females preferred males with exaggerated ornamentation ("brushes added" vs "no ornamentation" video, Hebets 2005). Follow-up experiments with S. uetzi suggest that the seismic and visual signals interact such that the seismic signal alters a female's visual attention (Hebets 2005). A recent study using live manipulated males questions the significance of this intersignal interaction for inexperienced females (Hebets et al. 2006) but suggests that the pigmentation observed in S. uetzi may be important in female mate choice learning. The importance of early experience on adult mate choice was previously demonstrated in S. uetzi as females were more likely to mate with a male of a familiar versus unfamiliar foreleg pattern (Hebets 2003). In the same study, females were more likely to cannibalize males possessing an unfamiliar foreleg pattern, suggesting strong selection on male ornamentation, maturation time, and/or male behavior (Hebets 2003).
While the tibia I brushes of many Schizocosa species have attracted much scientific attention, such morphological modifications are also found in other genera within the subfamily Lycosinae Sundevall 1833 (sensu Dondale 1986) (Table 1). Alopecosa barbipes (Sundevall 1833), for example, was listed as junior synonym of A. accentuata (Latreille 1817) by Lugetti & Tongiorgi (1969), and the presence (A. barbipes) or absence (A. accentuata) of tibial brushes was previously regarded as intraspecific variation. Subsequently, A. barbipes was removed from this synonymy based on morphological, behavioral and ecological differences (Dahlem et al. 1987; Cordes & Helversen 1990) and recent molecular studies confirmed the identity of A. barbipes as a separate species (Vink & Mitchell 2002). Bushy setae on the first tibia of males can also be found in other subfamilies of wolf spiders (Table 1). Two species of Evippomma Roewer 1959, E. plumipes (Lessert 1936) and E. squamulatum (Simon 1898), carry a striking fringe of black setae on the ventral and dorsal side of the first tibia (Fig. 3; also Alderweireldt 1992). The males of Artoria schizocoides n. sp. carry unique spatulate setae on the ventral side of their first tibia (Fig. 4; see also below). Other segments in addition to the tibiae may carry conspicuous modified setae. The males of Pirata cantralli Wallace & Exline 1978 have long curly setae on the metatarsi of the front legs (Dondale & Redner 1990). Some species of Pardosa C.L. Koch 1847 have conspicuous setae on the tarsi, metatarsi and tibia (Tongiorgi 1966a, b). Although a similar function as in Schizocosa is likely, there is no experimental evidence on the significance of these structures in these species.
The excessive setation observed in some wolf spider species may not function solely in a reproductive context. For example, in some Australian species currently listed in Hogna Simon 1885 males possess very fine, long setae around the whole circumference of the front tibia (Table 1; also Framenau et al. 2006). In contrast to the setation in Alopecosa, Schizocosa, Evippomma, Pardosa and Artoria, these setae are less conspicuous in live specimens and thus a role in visual signaling appears doubtful. When disturbed, males run with their front legs raised high in the air, suggesting a putative role in sensory perception and information gathering (Framenau pers. obs.). However, there is currently no experimental evidence for this function and detailed studies of setae structure may elucidate a putative role in sensory perception.
In summary, morphological modifications of the front legs in wolf spiders can be found in most of the currently recognized subfamilies (Dondale 1986; Zyuzin 1993; Framenau 2007). They are generally absent in the larger, burrowing and mainly nocturnal species, for example in the genera Lycosa Latreille 1804 (Palaearctic) (e.g., Orta-Orcana et al. 1996), Geolycosa Montgomery 1904 (Nearctic, Palaearctic), Tasmanicosa Roewer 1959 and Venatrix Roewer 1960 (e.g., Cutler 2002) (both Australian). It appears that foreleg modifications are more common in smaller, diurnal species, which strengthens their putative function in visual signaling. Although numerous Schizocosa species have been the focus of elegant studies regarding female mate choice and the evolution of male foreleg dimorphism/ ornamentation, much remains to be learned. Foreleg ornamentation appears to function in different ways even among closely related Schizocosa species, suggesting that it may be difficult to make broad generalizations about the evolution of sexual dimorphisms in wolf spiders. However, studies of similar morphological modifications in other wolf spider taxa are needed and will certainly add to our general understanding of the evolution of sexual foreleg dimorphism.
Artoria is an Australasian genus, currently with 23 representatives from the Philippines in the North to New Zealand in the South (Framenau 2002, 2004, 2005b; Framenau et al. 2006). However, a large number of unnamed species have been found in Australian and Pacific collections and the genus is believed to include more than 80 species in Australia alone (Framenau, personal observation). Artoria is characterized by a male pedipalp with a bifurcate or spoon-shaped apically directed tegular (= median) apophysis with a narrow base (Framenau 2002). Recent molecular studies suggest that Artoria as currently defined may not represent a monophyletic group (Murphy et al. 2006), however all currently described Artoria species belong to the Australasian/Pacific subfamily Artoriinae that received very good nodal support (Vink et al. 2002; Murphy et al. 2006). This subfamily can easily be identified by the presence of a basoembolic apophysis in the male pedipalp (Framenau 2007). Other genera within this clade include Anoteropsis L. Koch 1877 and Notocosa Vink 2002 (Vink 2002), Tetralycosa Roewer 1960 (Framenau et al. 2006) and Diahogna Roewer 1960 (Framenau 2006).
Descriptions are based on specimens preserved in 70% EtOH. A female epigynum was prepared for examination by submersion in lactic acid for 24 h. Scanning electron microscope (SEM) images were taken with a Carl Zeiss Leo 1420VP (Oberkochen, Germany) after fixing the respective spider parts in Karnovsky's fixative (Sheehan & Hrapchak 1980) and osmic acid. For clarity, the illustrations of genitalia omit the setae. The morphological nomenclature follows Framenau (2002). All material investigated is lodged at the Western Australian Museum, Perth, Australia (WAM).
Abbreviations.--Measurements are in mm: total body length (TL), carapace length (CL) and width (CW), abdomen length (AL) and width (AW). Eyes: anterior row of eyes (AE), anterior median (AME), anterior lateral (ALE), posterior row of eyes (PE), posterior median (PME), posterior lateral (PLE).
Artoria schizocoides new species Figs. 4-11
Types examined.--Holotype male, Australia, Western Australia: Bluff Knoll, Stirling Range National Park, 34[degrees]23'S, 118[degrees]15'E, 19 March 1996, S. Barrett, site 230, wet pitfall trap (WAM T53800). Paratypes: 1 male, 4 females, Bluff Knoll, Stirling Range National Park, Western Australia, Australia (34[degrees]22'56"S, 118[degrees]14'55"E), 7 September 1995, S. Barrett, site 214, 900m, pitfall traps (WAM T53799, T53875).
Other material examined.--AUSTRALIA: Western Australia: 1 [??], 1 [??], Alcoa mine, NE Jarrahdale, 32[degrees]17'S, 116[degrees]08'E (WAM T44717); 2 [??], Alcoa mine site & forest, N and NW Jarrahdale, 34[degrees]54'S, 117[degrees]55'E (WAM 97/ 583-4); 51 [??], 10 [??], Dwellingup, 32[degrees]43'S, 116[degrees]04'E (WAM T42134, T53762-76); 1 [??], Forth River, 45 km SE Northcliffe, 34[degrees]50'S, 116[degrees]26'E (WAM T65102); 1 [??], 1 [??], Jarrahdale, 32[degrees]20'S, 116[degrees]03'E (WAM T55764-5); 7 [??], 2 [??], Manjimup, 32[degrees]15'S, 116[degrees]09'E (WAM T53777-9); 15 [??], 4 [??], Mt. Cooke, 32[degrees]25'S, 116[degrees]18'E (WAM 98/2168, T53780-2, T62483, T65097; T65595); 60 [??], 3 [??], Mt. Lindesay, 34[degrees]50'30"S, 117[degrees]18'21"E (WAM T53807-10); 3 [??], 1 [??], Porongurup National Park, 34[degrees]40'56"S, 117[degrees]51'59"E (WAM T53805); 1 [??], Quinninup, nearby, 34[degrees]26'S, 116[degrees]15'E (WAM T65093); 21 [??], 4 [??], Stirling Range National Park, Bluff Knoll, 34[degrees]23'S, 118[degrees]15'E (WAM T53799, 53801-3); 3 [??], 4 juv., Stirling Range National Park, 12 km S Bluff Knoll, 34[degrees]29'S, 116[degrees]15'E (WAM T55578); 1 [??], Stirling Range National Park, Mondurup Peak, 34[degrees]24'18"S, 117[degrees]48'44"E (WAM T53804); 29 [??], 14 [??], 7 juveniles, Stirling Range National Park, S face of Pyongurup Peak, 34[degrees]22'17"S, 118[degrees]19'20"E (WAM T53761); 1 [??], 1 [??], Stirling Range National Park, The Cascades, 34_22[degrees]29'S, 118[degrees]14'17"E (WAM T53832); 1 [??], Sues Bridge, 50 km SW Nannup, 34[degrees]05'S, 115[degrees]40'E (WAM T65136).
Etymology.--The specific name is an adjective in apposition and refers to the wolf spider genus Schizocosa, the best studied genus in relation to the behavioral significance of brushed front legs in males.
Diagnosis.--Artoria schizocoides is the only Artoria species known to the authors of which males have spatulate setae on the ventral side of the tibia of the first leg. The epigynum of females remotely resembles that of A. cingulipes, however, A. schizocoides is much smaller and darker in colorations.
[FIGURES 5-9 OMITTED]
Description.--Male (holotype WAM T53800): Carapace: dorsal line straight in lateral view, head flanks vertical; carapace very dark brown; brown median band, as wide as PLE anteriorly but narrowing and brightening posteriorly, distinctly yellow behind fovea; indistinct brown submarginal bands; head region very dark brown, base of eyes black; dark gray radial pattern; scarce cover of short white setae, slightly denser in head region; few longer bristles in head region; one very long bristle between AME, two long bristles between ALE; AE strongly procurved. Sternum: yellow; gray pigmentation; sparsely covered with brown bristles, which are longer towards margins. Labium: brown, front end truncated and white. Chelicerae: dark brown, falces yellow; few long bristles in basal half; three retromarginal teeth, with the basal smallest, three promarginal teeth, with the medium largest. Pedipalp (Figs. 5-7, 10): cymbium dorsally with scopulate setae in apical half; apical tip of tegular apophysis bent ventrally, small protrusion on its apical edge; embolus reaches to about three quarters length of sclerotized groove of terminal apophysis (Fig. 7). Abdomen: dark olive gray; indistinct brown lanceolate heart mark in anterior half; mottled with brown spots; sparsely covered with white and, less dense, black setae; venter yellowish gray; three indistinct gray longitudinal bands; spinnerets with brown pigmentation. Legs: leg formula IV > I > III > II; femur I dark gray, femora II-IV dorsally brown with three indistinct dark annulations, ventrally yellow; tibia I black, ventrally with dense brush of spatulate setae (Fig. 4), tibiae II-IV light brown with indistinct annulations; metatarsus I yellow with contrasting black base, metatarsi II-IV brown with indistinct annulations; tarsus I yellow, tarsi II-IV brown; spination of leg I: Femur: 3 dorsal, 1 apicoprolateral; tibia: 3 ventral pairs, 2 prolateral; metatarsus: 3 ventral pairs; 1 apicoventral.
[FIGURE 10 OMITTED]
Female (based on paratype WAM T53875): Carapace and sternum: coloration and setae arrangement as male but carapace slightly lighter; AE strongly procurved. Labium: brown, front end truncated and white. Chelicerae: light brown, claws dark brown, brown bristles medially; dentition as male. Abdomen: dorsally uniformly olive-gray; indistinct lighter heartmark in anterior half and two light patches in posterior half; covered with short brown setae; venter olive-gray with irregular small yellow spots laterally and in two longitudinal lines medially; spinnerets yellow. Epigynum, ventral view (Fig. 8): Simple and round sclerotized ring, white centrally. Epigynum, dorsal view (Fig. 9): Large kidneyshaped complex of spermathecae and copulatory ducts. Legs: Leg formula IV > II > I > III; all segments light brown with distinct annulations; spination of leg I: Femur: 3 dorsal, 1 apicoprolateral; tibia: 2 ventral pairs, 1 apicoprolateral; metatarsus: 3 ventral pairs.
[FIGURE 11 OMITTED]
Measurements: male holotype WAM T53800 (female paratype WAM T53875): TL 3.24 (5.43), CL 1.88 (2.11), CW 1.30 (1.53). Eyes: AME 0.06 (0.06), ALE 0.06 (0.06), PME 0.26 (0.26), PLE 0.20 (0.20). Row of eyes: AE 0.35 (0.43), PME 0.69 (0.75), PLE 0.75 (0.87). Sternum (length/width) 0.87/0.81 (0.93/0.81). Labium (length/width) 0.23/0.20 (0.35/0.29). AL 1.56 (3.04), AW 0.98 (2.31). Legs: Lengths of segments (femur + patella/ tibia + metatarsus + tarsus + total length): Pedipalp 0.69 + 0.61 + - + 0.66 = 1.96, I 1.36 + 1.62 + 0.95 + 0.58 + 4.51, II 1.27 + 1.45 + 0.95 + 0.58 = 4.25, III 1.19 + 1.30 + 1.13 + 0.66 = 4.28, IV 1.59 + 1.82 + 1.88 + 1.13 = 6.42 (Pedipalp 0.67 + 0.75 + - + 0.52 = 1.94, I 1.30 + 1.59 + 0.93 + 0.58 = 4.40, II 1.27 + 1.50 + 1.01 + 0.55 = 4.33, III 1.24 + 1.45 + 1.16 + 0.61 = 4.46, IV 1.53 + 2.11 + 1.88 + 0.81 = 6.33).
Variation: males (females) (range, mean [+ or -] s.d.): TL 3.32-3.90, 3.49 [+ or -] 0.22; CL 1.73-1.96, 1.79 [+ or -] 0.09; CW 1.21-1.39, 1.28 [+ or -] 0.05; n = 10 (TL 3.90-5.64, 4.64 [+ or -] 0.53; CL 1.79-2.17, 1.99 [+ or -] 0.17; CW 1.27-1.50, 1.36 [+ or -] 0.09; n = 10).
Distribution.--Southwest Western Australia (Fig. 11).
Natural history.--Artoria schizocoides appears to mature in winter. Most records of adult females and males are from a period between June and September, with occasional reports from October and November. The species seems to prefer dry to moderately moist forests in mountainous regions.
We are indebted to Gail Stratton and Ansie Dippenaar-Schoeman who provided material for this study. Young-Bo Lee and An-Ja Ko (National Institute of Agricultural Science, Seoul, Korea) took the SEM photographs. Torbjorn Kronestedt provided helpful and constructive comments on an earlier draft of this manuscript. Julianne Waldock initially directed the senior author's attention to the small brush-legged A. schizocoides in the collection of the WAM. This investigation forms part of a revision of Australian wolf spiders funded by the Australian Biological Resources Study (ABRS) to Mark Harvey (Western Australian Museum) and Andy Austin (University of Adelaide).
Manuscript received 2 April 2006, revised 17 September 2006.
Alderweireldt, M. 1992. A taxonomic revision of the African wolf spider genus Evippomma Roewer, 1959 (Araneae, Lycosidae). Journal of African Zoology 106:153-167.
Alderweireldt, M. & R. Joque. 1991. A remarkable new genus of wolf spiders from southwestern Spain (Araneae, Lycosidae). Bulletin de l'Institut Royal des Sciences Naturelles de Belgique, Entomologie 61:103-111.
Andersson, M. 1994. Sexual Selection. Princeton University Press, Princeton, New Jersey. 624 pp. Cordes, D. & O.v. Helversen. 1990. Indications for the existence of Alopecosa barbipes (Sundevall 1832) as a sibling species to Alopecosa accentuata (Latreille 1817). Results of morphological, ethological and biogeographical studies. Bulletin de la Societe Europeenne d'Arachnologie, hors serie 1:70-74.
Cutler, A.R. 2002. Courtship in the wolf spider Venatrix lapidosa (Araneae: Lycosidae). Honours Thesis, The University of Melbourne, Australia. Dahlem, B., C. Gack & J. Martens. 1987. Balzverhalten von Wolfspinnen der Gattung Alopecosa. Zoologische Betrage (N.F.) 31:151-164.
Darwin, C. 1871. The Descent of Man, and Selection in Relation to Sex. J. Murray, London. 797 pp.
Dondale, C.D. 1969. Two new species of the spider genus Schizocosa (Araneida: Lycosidae) from the Great Lakes region. Canadian Journal of Zoology 47:751-758.
Dondale, C.D. 1986. The subfamilies of wolf spiders (Araneae: Lycosidae). Pp. 327-332. In Actas X Congreso Internacional de Aracnologia, Jaca, Espana (J.A. Barrientos, ed.). Volume 1.
Dondale, C.D. & J.H. Redner 1990. The Insects and Arachnids of Canada, Part 17. The Wolf Spiders, Nursery Web Spiders, and Lynx Spiders of Canada and Alaska (Araneae: Lycosidae, Pisauridae, and Oxyopidae). Biosystematics Research Centre, Ottawa, Ontario, Canada. 383 pp.
Dondale, C.D., M.L. Jimenez & G. Nieto. 2005. A new genus of wolf spiders from Mexico and southern United States, with description of a new species from Texas (Araneae: Lycosidae). Revista Mexicana de Biodiversidad 76:41-44.
Elgar, M.A., N. Ghaffar & A.F. Read. 1990. Sexual dimorphism in leg length among orb-weaving spiders: a possible role for sexual cannibalism. Journal of Zoology, London 222:455-470.
Fairbairn, D.J. 1997. Allometry for sexual size dimorphism: pattern and process in the coevolution of body size in males and females. Annual Review of Ecology and Systematics 28:659-687.
Framenau, V.W. 2002. Review of the wolf spider genus Artoria Thorell (Araneae, Lycosidae). Invertebrate Systematics 16:209-235.
Framenau, V.W. 2004 [imprint date 2003]. Two alpine wolf spiders of Australia: Artoria alta sp. nov., and the male of Lycosa musgravei McKay, 1974 (Araneae, Lycosidae). Proceedings of the Royal Society of Victoria 115:27-34.
Framenau, V.W. 2005a. Gender specific differences in activity and home range reflect morphological dimorphism in wolf spiders (Araneae, Lycosidae). Journal of Arachnology 33:334-346.
Framenau, V.W. 2005b. The wolf spider genus Artoria Thorell (Araneae, Lycosidae) in Australia: new synonymies and generic transfers. Records of the Western Australian Museum 22:265-292.
Framenau, V.W. 2006. Revision of the wolf spider genus Diahogna Roewer, 1960 (Araneae, Lycosidae). Journal of Natural History 40:273-292.
Framenau, V.W. 2007. Revision of the new Australian genus Artoriopsis in a new subfamily of wolf spiders, Artoriinae (Araneae: Lycosidae). Zootaxa 1391:1-34.
Framenau, V.W., T.B. Gotch & A.D. Austin. 2006. The wolf spiders of artesian springs in arid South Australia, with a revalidation of Tetralycosa (Aranae, Lycosidae). Journal of Arachnology 34:1-36.
Hebets, E.A. 2003. Subadult experience influences adult mate choice in an arthropod: exposed female wolf spiders prefer males of a familiar phenotype. Proceedings of the National Academy of Science USA 100:13390-13395.
Hebets, E.A. 2005. Attention-altering interactions among signals in multimodal wolf spider courtship displays. Behavioral Ecology 16:75-82.
Hebets, E.A. & D.R. Papaj. 2005. Complex signal function: developing a framework of testable hypotheses. Behavioral Ecology and Sociobiology 57:197-214.
Hebets, E.A. & G.W. Uetz. 1999. Female responses to isolated signals from multi-modal male courtship displays in the wolf spider genus Schizocosa (Araneae: Lycosidae). Animal Behaviour 57: 865-872.
Hebets, E.A. & G.W. Uetz. 2000. Leg ornamentation and the efficacy of courtship display in four species of wolf spider (Araneae: Lycosidae). Behavioral Ecology and Sociobiology 47:280-286.
Hebets, E.A., K. Cuasay & P.K. Rivlin. 2006. The role of visual ornamentation in female choice of a multimodal male courtship display. Ethology 112:1062-1070.
Hedrick, A.V. & E.J. Temeles. 1989. The evolution of sexual dimorphism in animals: hypotheses and tests. Trends in Ecology & Evolution 4:136-138.
Heimer, S. & W. Nentwig. 1991. Spinnen Mitteleuropas. Paul Parey, Stuttgart, Germany. 543 pp.
Juberthie-Jupeau, L., A. Lopez & T. Kronestedt. 1990. Structure et ultrastructure de la glande tibiale chez le male d'Alopecosa cuneata (Clerck) (Araneae, Lycosidae). Revue Arachnologique 9: 63-77.
Kronestedt, T. 1986. A presumptive pheromoneemitting structure in wolf spiders (Araneae, Lycosidae). Psyche 93:127-131.
Kronestedt, T. 1990. Separation of two species standing as Alopecosa aculeata (Clerck) by morphological, behavioural and ecological characters, with remarks on related species in the pulverulenta group. Zoologica Scripta 19:203-225.
Kronestedt, T. & Y.M. Marusik. 2002. On Acantholycosa solituda (Levi & Levi) and A. sterneri (Marusik) (Araneae: Lycosidae), a pair of geographically distant allied species. Acta Arachnologica 51:63-71.
Lugetti, G. & P. Tongiorgi. 1969. Ricerche sul genere Alopecosa Simon (Araneae-Lycosidae). Atti de la Societa Toscana di Scienze Naturali (B) 76: 1-100.
McClintock, W.J. & G.W. Uetz. 1996. Female choice and pre-existing bias: visual cues during courtship in two Schizocosa wolf spiders. Animal Behaviour 52:167-181.
Moya-Larano, J., P.W. Taylor & C. Fernandez-Montraveta. 2003. Body patterns as potential amplifiers of size and condition in a territorial spider. Biological Journal of the Linnean Society 78: 355-364.
Murphy, N.P., V.W. Framenau, S.C. Donellan, M.S. Harvey, Y.-C. Park & A.D. Austin. 2006. Phylogenetic reconstruction of the wolf spiders (Araneae: Lycosidae) using sequences from the 12S rRNA, 28 rRNA and NADH1 genes: implications for classification, biogeography and the evolution of web building behavior. Molecular Phylogenetics and Evolution 38:583-602.
Orta-Orcana, J.M., J. Moya-Larano & J.A. Barrientos. 1996. Precopulatory male ethograms of three species of Lycosa Latreille 1804 (Araneae: Lycosidae) of the Iberian peninsula. Revue Suisse de Zoologie, volume hors serie II:515-522.
Prenter, J., W.I. Montgomery & R.W. Elwood. 1997. Sexual dimorphism in northern temperate spiders: implications for the differential mortality model. Journal of Zoology, London 243:341-349.
Prenter, J., R.W. Elwood & W.I. Montgomery. 1998. No association between sexual size dimorphism and life histories in spiders. Proceedings of the Royal Society of London, Series B 265: 57-62.
Prenter, J., R.W. Elwood & W.I. Montgomery. 1999. Sexual size dimorphism and reproductive investment by female spiders: a comparative analysis. Evolution 53:1987-1994.
Reynolds, J.D. & P.H. Harvey. 1994. Sexual selection and the evolution of sex differences. Pp. 53-70. In The Differences Between the Sexes (R.V. Short & E. Balaban, eds.). Cambridge University Press, Cambridge, UK.
Scheffer, S.J., G.W. Uetz & G.E. Stratton. 1996. Sexual selection, male morphology, and the efficacy of courtship signalling in two wolf spiders (Araneae: Lycosidae). Behavioral Ecology and Sociobiology 38:17-23.
Selander, R.K. 1972. Sexual selection and dimorphism in birds. Pp. 180-230. In Sexual Selection and the Descent of Man, 1871-1971 (D.C. Campbell, ed.). Aldine, Chicago, Illinois.
Sheehan, D. & B. Hrapchak. 1980. Theory and Practice of Histotechnology. Second edition. Battelle Press, Ohio. 480 pp.
Shine, R. 1989. Ecological causes for the evolution of sexual dimorphism: a review of the evidence. Quarterly Review of Biology 64:419-461.
Stratton, G.E. 1991. A new species of wolf spider, Schizocosa stridulans (Araneae, Lycosidae). Journal of Arachnology 19:29-39.
Stratton, G.E. 2005. Evolution of ornamentation and courtship behaviour in Schizocosa: insights from a phylogeny based on morphology (Araneae, Lycosidae). Journal of Arachnology 33: 347-377.
Tanaka, H. 1993. Lycosid spiders of Japan XI. The genus Pardosa C.L. Koch--paludicola-group. Acta Arachnologica Tokyo 42:159-171.
Tongiorgi, P. 1966a. Italian wolf spiders of the genus Pardosa (Araneae, Lycosidae). Bulletin of the Museum of Comparative Zoology 134:275-334.
Tongiorgi, P. 1966b. Wolf spiders of the Pardosa monticola group (Araneae, Lycosidae). Bulletin of the Museum of Comparative Zoology 134: 335-359.
Uetz, G.W. & J.A. Roberts. 2002. Multi-sensory cues and multi-modal communication in spiders: insights from video/audio playback studies. Brain, Behavior & Evolution 59:222-230.
Uetz, G.W., R. Papke & B. Kilinc. 2002. Influence of feeding regime on body size, body condition and male secondary sexual character in Schizocosa ocreata wolf spiders (Araneae, Lycosidae): condition-dependence in a visual signalling trait. Journal of Arachnology 30:461-469.
Vink, C.J. 2002. Lycosidae (Arachnida: Araneae). Fauna of New Zealand 44:1-94.
Vink, C.J. & A.D. Mitchell. 2002. 12S DNA sequence data confirms the separation of Alopecosa barbipes and Alopecosa accentuata (Araneae: Lycosidae). Bulletin of the British Arachnological Society 12:242-244.
Vink, C.J., A.D. Mitchell & A.M. Paterson. 2002. A preliminary molecular analysis of phylogenetic relationships of Australasian wolf spider genera (Araneae, Lycosidae). Journal of Arachnology 30:227-237.
Vogel, B.R. 2004. A review of the spider genera Pardosa and Acantholycosa (Araneae, Lycosidae) of the 48 contiguous United States. Journal of Arachnology 32:55-108.
Walker, S.E. & A.L. Rypstra. 2001. Sexual dimorphism in functional response and trophic morphology in Rabidosa rabida (Araneae: Lycosidae). American Midland Naturalist 146:161-170.
Walker, S.E. & A.L. Rypstra. 2002. Sexual dimorphism in trophic morphology and feeding behavior of wolf spiders (Araneae: Lycosidae) as a result of differences in reproductive roles. Canadian Journal of Zoology 80:679-688.
Zyuzin, A.A. 1993. Studies on the wolf spiders (Araneae: Lycosidae). I. A new genus and species from Kazakhstan, with comments on the Lycosinae. Memoirs of the Queensland Museum 33: 693-700.
Volker W. Framenau: Department of Terrestrial Invertebrates, Western Australian Museum, Locked Bag 49, Welshpool DC, Western Australia 6986, Australia. E-mail: firstname.lastname@example.org
Eileen A. Hebets: School of Biological Sciences, University of Nebraska, 348 Manter Hall, Lincoln, Nebraska 68588 USA.
Table 1.--Morphological modifications of legs in male wolf spiders. Abbreviations: pt = patella; tb = tibia; t = tarsus, mt = metatarsus. Roman numbers refer to leg (e.g., I = leg 1). Species Distribution Morphological (Platnick 2006) modification of legs Piratinae (sensu Zyuzin 1993) Acantholycosa solituda Nearctic (Rocky tb and mt I and II with (Levi & Levi 1951) Mountains) dense cover of la- nate pubescence of long, light, curved, fine setae A. sterneri (Marusik 1993) Palaearctic tb and mt I and II with (Mongolia, dense cover of la- Sth Siberia) nate pubescence of long, light, curved, fine setae Pirata canadensis Dondale Canada t of leg I curved & Redner 1981 P. cantralli Wallace & USA, Canada tb I & mt I swollen, Exline 1978 mt I with many long curly setae ventrally Lycosinae (sensu Dondale 1986) Alopecosa cuneata Palaearctic pt I & II slightly (Clerck 1757) swollen, tb I extremely swollen and slightly elongated, tb II slightly swollen A. pulverulenta (Clerck Holarctic pt & tb I & II slightly 1757) swollen A. barbipes (Sundevall Palaearctic tb and mt I with ven- 1833) tral brushes Camptocosa parallela Southern USA, tb and basal half of mt (Banks 1898 Mexico I with long dense black setae C. texana Dondale, Texas (USA) tb and basal half of mt Jimenez & Nieto 2005 I with brush of long dark setae, more dense dorsally and ventrally Hogna crispipes (L. Koch Australia, mt I with thin, hair- 1876), H. kuyani Pacific like setae around Framenau, Gotch & whole circumference Austin 2006, H. diyari Framenau, Gotch & Austin 2006 Schizocosa aulonia Dondale USA tb I with brushy setae 1969 S. bilineata (Emerton Nearctic tb I with brush of 1885) erect black setae S. crassipes (Walckenaer USA tb I with brush of 1837) erect black setae S. ocreata (Hentz 1844) Nearctic tb I with brush of (varying morphospecies erect black setae differentiated in Stratton (2005) S. salsa Barnes, 1953 USA tb I with apical brush of erect black setae S. segregata Gertsch and USA tb I with brushy setae Wallace 1937 mainly ventrally S. stridulans Stratton, USA tb I with brushy setae 1984 Pardosinae (sensu Dondale 1986) Pardosa agrestis Western & Cen- t, rut & apical part of purbeckensis F.O. tral Europe tib I with long, rig- P-Cambridge 1895 id, straight setae P. astrigera L. Koch 1878 Palaearctic tb and rut I with many long, straight setae P. ilguensis Nosek 1905 Turkey tb & rut I & II slightly swollen and covered with short setae, scopulous ventrally P. mixta (Kulczyn'ski Palaearctic t, rut & apical part of 1887) tb I with very long lateral and forward- ly directed setae P. plumipes (Thorell 1875) Palaearctic tb & rut I with very long hair-like setae P. vancouveri Emerton 1917 USA, Canada rut & t I swollen P. vittata (Keyserling Europe to Geor- rut II with ventrally 1863) gia with long setae Evippinae (sensu Zyuzin 1985) Evippomma plumipes Africa tb I with plumose se- (Lessert 1936 tae, rut I densely covered with white setae E. squamulatum (Simon Africa tb I with plumose se- 1898) tae Artorfinae (sensu Framenau 2007) Artoria flavimana Simon Australia extremely elongated 1909 front leg A. schizocoides n. sp. Western Austra- ventral brush of spate- lia (this late setae study) Species Reference Piratinae (sensu Zyuzin 1993) Acantholycosa solituda Kronestedt & Marusik (Levi & Levi 1951) (2002, fig. 14) A. sterneri (Marusik 1993) Kronestedt & Marusik (2002, figs 15, 16) Pirata canadensis Dondale Dondale & Redner & Redner 1981 (1990, fig. 371) P. cantralli Wallace & Dondale & Redner Exline 1978 (1990, fig. 375) Lycosinae (sensu Dondale 1986) Alopecosa cuneata Fig. 1; Dahlem et al. (Clerck 1757) (1987, figs. lc, 3, 4), Kronestedt (1986, fig. 1), Kro- nestedt (1990, fig. 13H) A. pulverulenta (Clerck Dahlem et al. (1987, 1757) fig. 1b) (doubtful as per T Kronestedt, pers. comm.) A. barbipes (Sundevall Dahlem et al. (1987, 1833) fig. 1d) Camptocosa parallela Dondale et al. (2005) (Banks 1898 C. texana Dondale, Dondale et al. (2005) Jimenez & Nieto 2005 Hogna crispipes (L. Koch Framenau et al. (2006) 1876), H. kuyani Framenau, Gotch & Austin 2006, H. diyari Framenau, Gotch & Austin 2006 Schizocosa aulonia Dondale Dondale (1969), Strat- 1969 ton (2005, fig. 23) S. bilineata (Emerton Dondale & Redner 1885) (1990), Stratton (2005, fig. 25) S. crassipes (Walckenaer Fig. 2; Stratton (2005, 1837) fig. 27) S. ocreata (Hentz 1844) Dondale & Redner (varying morphospecies (1978, fig. 5), Don- differentiated in dale & Redner Stratton (2005) (1990, fig. 50), Stratton (1991, fig. 11; 2005, fig. 29- 31 S. salsa Barnes, 1953 Stratton (2005, fig. 24) S. segregata Gertsch and Stratton (2005, fig. 26) Wallace 1937 S. stridulans Stratton, Stratton (1991, fig. 13; 1984 2005, fig. 28) Pardosinae (sensu Dondale 1986) Pardosa agrestis Tongiorgi (1966b, fig. purbeckensis F.O. 21), Heimer & Nen- P-Cambridge 1895 twig (1991, fig. 860.20 P. astrigera L. Koch 1878 Tanaka (1993) P. ilguensis Nosek 1905 Tongiorgi (1966b, fig. 20 P. mixta (Kulczyn'ski Tongiorgi (1966a, fig. 1887) 106; 1966b, fig. 23); Heimer & Nentwig (1991, fig. 859.5) P. plumipes (Thorell 1875) Tongiorgi (1966b, fig. 22 P. vancouveri Emerton 1917 Vogel (2004, fig. 127) P. vittata (Keyserling Tongiorgi (1966a, fig. 1863) 6 Evippinae (sensu Zyuzin 1985) Evippomma plumipes Alderweireldt (1992) (Lessert 1936 E. squamulatum (Simon Fig. 3; Alderweireldt 1898) (1992, fig. 1d) Artorfinae (sensu Framenau 2007) Artoria flavimana Simon Framenau (2002) 1909 A. schizocoides n. sp. Fig. 4
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|Author:||Framenau, Volker W.; Hebets, Eileen A.|
|Publication:||The Journal of Arachnology|
|Date:||Jan 1, 2007|
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