1999. The Journal of Arachnology 27:547±549

RESEARCH NOTE ON SOFANAPIS ANTILLANCA (ARANEAE, ANAPIDAE) AS A KLEPTOPARASITE OF AUSTROCHILINE SPIDERS (ARANEAE, AUSTROCHILIDAE)

Kleptoparasitic habits are well known in logs, or in Berlese samples of leaf litter and certain spiders, notably some mysmenids and moss (Platnick & Forster 1989). During recent members of the theridiid genus Argyrodes Si- ®eld work, we found some specimens on aus- mon 1864 (Elgar 1993). Members of the Dic- trochiline webs, and after a systematic exam- tynidae, Heteropodidae, Oonopidae, Saltici- ination of webs, found evidence of kleptopar- dae, and Symphytognathidae have also been asitic behavior in these anapids. During the recorded as kleptoparasites of web-building day, individuals of S. antillanca were collect- spiders (Elgar 1993, table 1). We present here ed on austrochilid webs (of both Austrochilus the ®rst evidence of kleptoparasitism in the and Thaida species), hanging from threads, Anapidae, as well as the ®rst report of a klep- rather deep in the mouth of the funnel, but still toparasite associated with the primitive and visible with a headlamp. At night, when the relictual spider subfamily Austrochilinae. host is on its web, the anapids were mostly Austrochilines comprise two genera, Aus- concentrated around the opening of the funnel, trochilus Gertsch & Zapfe 1955 and Thaida closer to the horizontal web. They hang from Karsch 1880, restricted to the temperate for- the host web's threads (Fig. 1), or more often, ests of Chile and adjacent Argentina. They from an irregular mesh made of extremely ®ne build conspicuous, large (about 50±120 cm threads. That mesh is presumably constructed long), horizontal, aerial webs, consisting of a by the Sofanapis, as it has not been found in single layer of threads forming an irregular net non-infested webs. A web of an adult female (Forster et al. 1987; Zapfe 1955). The cribel- of Thaida peculiaris Karsch 1880 observed at late, whitish threads make the web easily vis- Aguas Calientes in the Parque Nacional Puy- ible. The horizontal net gradually bends into ehue, Osorno, Region X (Los Lagos), Chile, a concavity, forming a funnel that goes far was found to host several specimens of S. an- back into log cracks, tree roots, or rocks, end- tillanca, and in that web the thin (anapid) net ing in a retreat where the spider rests during was particularly dense. No orbwebs were the day. At night, the spider hangs under its found on any host web, nor was any insect web and can be seen combing cribellate silk, found caught in the presumed anapid silk. or feeding. Large prey items, up to the spider's Consequently, it seems that S. antillanca does body size, are wrapped with silk before being not construct its own web for prey capture. eaten. The type specimens of S. antillanca, collected The retreats of adult females often contain by pyrethrin fogging inside a rotten tree trunk much silk and several egg cases (Forster et al. (Platnick & Forster 1989), may actually have 1987). The web is repaired when damaged; come from an austrochilid web. and the newly constructed patches, with bluish A few hosts were observed while they were cribellate threads, are clearly discernible from feeding. We found several S. antillanca walk- the old portions, with powdered threads. Silk ing on the prey, some of them around the accumulation and web repair indicate that the host's mouth (Figs. 3±4). In those cases, al- web is persistent, a frequent characteristic of though visibility was far from ideal, there was the hosts of kleptoparasites (Elgar 1993). no evidence that the anapids were feeding Sofanapis antillanca Platnick & Forster from the ¯uids exposed by the chewing of the 1989 are very small spiders that were previ- austrochiline. In another situation, where a ously collected either by pyrethrin-fogging in host was feeding on a tipulid crane-¯y, an in-

547 548 THE JOURNAL OF ARACHNOLOGY

Figures 1±4.ÐSofanapis antillanca on webs of austrochilines. 1, Female walking on host web, from Chepu; 2, Austrochiline and S. antillanca feeding on a tipulid, from Contulmo (arrow points to the anapid feeding on the tipulid's leg); 3, Austrochiline and S. antillanca feeding on a beetle, from Contulmo (arrows point to the four anapids); 4, Same, closer view. dividual of S. antillanca was seen feeding di- dence on the host (as apparently occurs with rectly from the insect's leg (Fig. 2). On an- Curimagua bayano Forster & Platnick 1977, other occasion, a specimen of S. antillanca a symphytognathid with reduced mouthparts, was observed feeding alone on a small mos- Vollrath 1978). Moreover, the presence of oc- quito caught in an araneid web (also in the casional individuals of S. antillanca on webs Parque Nacional Puyehue). This observation of araneids and hahniids (in the Monumento suggests that the anapid might have some abil- Natural Contulmo in Arauco, Region VIII, ity to locate prey in the host's web, indepen- Chile), as well as in Berlese samples of leaf dent of the movements of the host, and that litter and moss, indicates that these spiders are S. antillanca is not adapted to kleptoparasi- not obligately associated with austrochilines. tism to the extreme condition of total depen- However, the particularly high density of S. RAMIREZ & PLATNICKÐA KLEPTOPARASITE ANAPID 549 antillanca collected on austrochiline webs (M. RamõÂrez) 1(6& 1juv, on uncollected austro- suggests a special association with these hosts. chiline's web (Fig. 1, MACN). Austrochilines are common in extremely to moderately moist forests of central and south- LITERATURE CITED ern Chile and adjacent Argentina. However, Elgar, M.A. 1993. Inter-speci®c associations in- the kleptoparasitic anapids were found only in volving spiders: kleptoparasitism, mimicry and the most humid localities. In addition to the mutualism. Mem. Queensland Mus., 33:411± 430. Puyehue and Contulmo localities noted above, Forster, R.R., N.I. Platnick & M.R. Gray. 1987. A Sofanapis have been taken from austrochiline review of the spider superfamilies Hypochiloidea webs at the following localities in Chile: Cal- and Austrochiloidea (Araneae, Araneomorphae). eta La Arena in Llanquihue, and 15 km S of Bull. American Mus. Nat. Hist., 185:1±116. Chepu in Chiloe (both in Region X). Several Vollrath, F. 1978. A close association between two intense but fruitless searches were performed spiders: Curimagua bayano synecious on a Di- in less humid localities, in both Chile and Ar- plura species. Psyche, 85:347±353. gentina. Zapfe, H.C. 1955. Filogenia y funcioÂn en Austro- chilus manni Gertsch y Zapfe (Araneae±Hypo- Material examined.Ð(Most austrochilines were chilidae). Trab. Lab. Zool. Univ. Chile, 2:1±53. either juveniles or were not collected together with its kleptoparasites): CHILE: RegioÂn IX: CautõÂn, MartõÂn J. RamõÂrez: Graduate Fellow, Lab. Monumento Natural Contulmo, elev. 340 m, de ArtroÂpodos, Dept. de BiologõÂa, Univer- 38Њ01ЈS, 73Њ11ЈW, 13 February 1992 (N. Platnick, sidad de Buenos Aires, Pabellon II Ciudad P. Goloboff, M. RamõÂrez) 4& S. antillanca (Figs. 3, Universitaria, 1428 Buenos Aires, Argenti- 4, AMNH); 18 November 1993 (N. Platnick, K. na; Adscript, Museo Argentino de Ciencias Catley, M. RamõÂrez, T. Allen) 1( S. antillanca (Fig. Naturales ``Bernardino Rivadavia.'' 2, AMNH). RegioÂn X (Los Lagos): Osorno, P. Nac. Puyehue, Aguas Calientes, 12 February 1992 (Plat- Norman I. Platnick: Curator, Department nick, Goloboff, RamõÂrez) many (& S. antillanca of Entomology, American Museum of Nat- on a web of a female Thaida peculiaris Karsch ural History, Central Park West at 79th (AMNH). Llanquihue, Caleta La Arena, 30 January Street, New York, New York 10024-5192 1991 (M. RamõÂrez) 2(3& 2juv S. antillanca on a USA. web of a subadult ( austrochiline (MACN); same data, 2& 1 juv on uncollected austrochiline's web. Manuscript received 15 December 1997, revised 27 ChiloeÂ, Chepu, 15 km S de Chepu, 3 February 1991 April 1998.