1992. The Journal of Arachnology 20:67-68

CONJECTURES ON THE ORIGINS AND FUNCTION S OF A BRIDAL VEIL SPUN BY THE MALES O F CUPIENNIUS COCCINEUS (ARANEAE, CTENIDAE)

Bristowe (1958) called the tiny web spun by turning to her. Obviously, the male silk did no t courting males of Xysticus cristatus (Araneae, seriously affect the female's mobility. Thomisidae) over and around the female while In Cupiennius, females are known to use silk circling upon her a bridal veil . To my knowledge , as draglines, to wrap and tie large prey (e.g., grass- similar behavior of males has been reported for hoppers) to the substratum, to construct irregula r Nephila clavipes (Araneidae, Nephilidae; Rob- sheet webs partly or totally closing their retreats, inson & Robinson 1973, 1980), for Latrodectus to build egg sacs and loose and irregular "nursery tredecimguttatus (Araneidae, Theridiidae; Stern webs" for the newly hatched spiderlings. Males & Kullmann 1981), for Tibellus oblongus (Ara- use silk as draglines, to build sperm webs, an d neae, Philodromidae ; Stern & Kullmann 1981) , to immobilize large prey. During many years of for Ancylometes bogotensis (Araneae, Pisauridae ; experience in breeding spiders of the genus Cu- Merrett 1988) and for Dictyna volucripes (Ara- piennius, we never observed the behavior de - neae, Dictynidae; Starr 1988) . In these species , scribed above for C. coccineus males. I suggest the male places a few threads over the female . four interpretations, which are not mutually ex- In Pisaurina mica (Araneae, Pisauridae), the fe- clusive. (i) The male's spinning is the same be- male draws her legs I and II against her carapace havior as that shown when tying large prey to (in a flexed position) and the male wraps them the substratum. The male switches from court- with a veil of silk prior to copulation (Bruce & ship to predatory behavior and vice versa be- Carico 1988). cause the heterospecific female has attributes of Spiders of the neotropical genus Cupiennius both mate and prey. (ii) The observed behavior live in close association with particular plants , is a displacement activity. A heterospecific fe- mainly bromeliads, on which they receive vi- male that has attributes of mate and non-mate brations (e.g., from prey and mating partner) and and prey raises conflicts in the male . The kind emit vibratory signals during courtship (Barth et of displacement activity that arises (here: tying al. 1988). In a recent behavioral study of species of prey) is a matter of chance or of prevailing recognition and species isolation, we compared attributes of the female . (iii) Bridal veiling is part hetero- and intraspecific communication in thre e of the male's repertoire which he uses only whe n closely related species of the genus Cupiennius confronted with a particularly large and poten- (Barth & Schmitt 1991, Schmitt et al . 1990). In tially dangerous female . About 15% of the fe- 9 out of 14 trials, the females of C. salei (which males responding to males during vibratory are larger by about 30% than those of C. cocci- courtship attack the approaching male, and males news) responded to the vibratory courtship of C. smaller than females are at risk of being kille d coccineus males with their own vibratory court- by the female . Knowing this, we use pairs matched ship signals and both spiders finally met. When in size for breeding. Thus bridal veiling could mounting the female, three of the 9 males spun never have been observed in conspecific pairs o f attachment points onto the female's legs and cir- C. coccineus in our lab. (iv) Bridal veiling is an cled upon her for minutes while depositing sil k atavism. Males regress to a behavior inherited on her. The males interrupted this behavior to from, e. g., a pisaurid ancestor when confronted emit vibratory courtship signals. Whereas two with a particularly large and potentially danger- males copulated after a few minutes, the thir d ous female . The behavior has never been ob- made increasingly longer excursions on the bro- served in conspecific pairs for the same reason meliad consistently returning to the female an d as given in (iii). With the knowledge I have on continuing both his spinning behavior and vi- Cupiennius, I cannot refute any of the above con- bratory courtship. Finally, about two hours after jectures. The above hypotheses are nevertheles s the first contact between the heterospecifics, he testable. For example, one can compare films o f was attacked and killed by the female when re- males tying prey to the substratum with films o f 67

68 THE JOURNAL OF ARACHNOLOGY

males spinning a bridal veil (hypothesis i) or on e LITERATURE CITED can perform experiments using both female-larg - Barth, F. G., H. Bleckmann, J. Bohnenberger & E .-A. er and male-larger pairs of conspecifics, the pre- Seyfarth. 1988. Spiders of the genus Cupiennius diction being to observe bridal veils with female - Simon 1891 (Araneae, Ctenidae) II. On the vibra- larger pairs and no veils with male-larger pairs tory environment of a wandering spider. Oecologia , (hypotheses iii and iv) . 77:194-201 . Let us assume now that application of silk onto Barth, F . G. & A. Schmitt. 1991 . Species recognition the female is part of the male's courtship rep- and species isolation in wandering spiders (Cupien- . Behay . Ecol. Sociobiol., 29: ertoire in the species enumerated above . What nius specc., Ctenidae) 333-339 . functions does this behavior have? If the behav- Bristowe, W.S. 1958 . The World of Spiders . Collins, ior of the male handicaps the female during cop- London . ulation or causes at least a brief delay of her Bruce, J. A. & J. E. Carico. 1988. Silk use during activity after copulation, which seems to be the mating in Pisaurina mira (Araneae, Pisauridae) . J. case in Pisaurina mira (Bruce & Carico 1988), Arachnol., 16:1-4. then aggressive acts of the female and/or post - Christenson, T . E., S. G. Brown, W . A. Wenzl, E. M. copulatory chases after the male (common i n Hill & K. C. Goist. 1985. Mating behavior of the . Cupiennius coccineus and Latrodectus tredecim- Golden-Orb-Weaving spider, Nephila clavipes : I Female receptivity and male courtship . J. Comp. guttatus and present in Nephila clavipes ; Chris- . . 1985) should be less efficient . In this Psychol., 99:160-166 tenson et al Coddington, J . A. 1990. Cladistics and spider clas- view, the bridal veil "solution" is only purpose- sification: araneomorph phylogeny and the mono- ful in those spider species in which females are phyly of orbweavers (Araneae, Araneomorphae ; Or- aggressive toward males during or after copula- biculariae). Acta Zool . Fennica, 190 :75-88 . tion. Hence the number of species in which the Foelix, R. F. 1982. The Biology of Spiders. Harvard male applies silk to the female must depend on Univ. Press, Cambridge, Mass . female behavior. The close phylogenetic rela- Homann, H . 1975 . Die Stellung der Thomisidae an d tionship of Ctenidae and Pisauridae on the one der Philodromidae im System der Araneae (Cheli- hand, and the large taxonomic distance of Thom - cerata, Arachnida) . Z. Morph. Tiere, 80 :181-202. isidae and Dictynidae and Nephilidae and Ther- Merrett, P . 1988. Notes on the biology of the neo- Ancylometes bogotensis (Araneae: o tropical pisaurid, idiidae from each other and from the other tw Pisauridae) . Bull. British Arachnol. Soc., 7:197-201 . families (Homann 1975, Coddington 1990) o n Robinson, M . H. & B. Robinson . 1973. The stabi- the other hand, suggest that silk binding of the limenta of Nephila clavipes and the origins of sta- female by the male has evolved separately sev- bilimentum-building in araneids. Psyche, 80:277- eral times. But in view of the potentially lethal 287. weapons of spiders and of the fact that spiders Robinson, M. H. & B. Robinson. 1980. Comparativ e need to overcome cannibalistic tendencies when studies of the courtship and mating behavior of mating, I wonder (as do Bruce & Carico 1988) tropical araneid spiders. Pacific Insects Monogr., 36: why this behavior is not more widespread among 5-271 . . 1990. Daily . My answer is that aggressiveness Schmitt, A., M. Schuster & F . G. Barth male spiders locomotor activity pattern in three species of Cu- of females towards males during or after (and piennius (Araneae, Ctenidae) : The males are the even before) copulation is rare (Foelix 1982) or wandering spiders. J. Arachnol., 18:249-255 . at least much less common than spider folklor e Starr, C. K. 1988. Sexual behavior in Dictyna volu- says, which may explain why bridal veiling is so tripes (Araneae, Dyctinidae).'J. Arachnol;; 16:321,- rare. Most spiders appease their mates before approaching them. The conjectures presented in Stern; H. & E. Kullmann. 1981. Leben am seidenen this paragraph can be corroborated or refuted by Faden. Kindler, Munchen . investigating systematically the correlation be- Alain Schmitt: Institut fur Zoologie, Univer- tween female and male behavior (and size) in a s sitat Wien, Althanstr. 14, A-1090 Wien, Aus- many spider species as possible. tria. Supported by grant P7896 from the Austria n Science Foundation (FWF) to Friedrich G. Barth. Manuscript received August 1991, revised October 1991 .