Zoology 106 (2003): 223–231 © by Urban & Fischer Verlag http://www.urbanfischer.de/journals/zoology
Spinning activity of the spider Trogloneta granulum (Araneae, Mysmenidae): web, cocoon, cocoon handling behaviour, draglines and attachment discs
Jaromír Hajer* and Dana Rˇ eháková
Department of Biology, University J.E. Purkinje, Ústí nad Labem, Czech Republic
Received March 14, 2003 á Revised version received July 09, 2003 á Accepted July 13, 2003
Summary
The spider species Trogloneta granulum, which in the wild lives inside scree slopes, builds three-dimensional orb webs. During egg-laying and egg sac building, the females stay with their dorsa down at the central part of the web. In this process, the hub is used as a platform. The threads of the hub are not incorporated into the silk cover of the egg sac. The silk wall of the egg sac is very thin, with all the silken threads constituting it having a uniform ultrastructure. The silk wall of the egg sac and the spin- nerets are permanently linked by a dragline. Draglines produced by T. granulum affect the direction of movements of the fe- male carrying its cocoon. Egg sacs are handled using draglines. The low number of piriform glands leads to the formation of very simple attachment discs, which fix the individual threads to the substratum. Thread bundles are attached to the substratum by means of accumulated attachment discs.
Key words: spiders, Mysmenidae, silk, cocoon, draglines, attachment discs
Introduction sensu lato. The family of Mysmeidae includes 24 gen- era with 96 known species (Platnick, 2003). Griswold Trogloneta granulum Simon, 1922 is a rare European et al. (1998) consider the Mysmenidae to be a poorly species with an extramediterranean distribution (Ruûzˇicˇka, understood family. Little is known about the behaviour 1994; Buchar and Ruûzˇicˇka, 2002). These spiders live on of these tiny spiders (Schütt, 2003). Eberhard (1987) the bottom side of stones in damp areas of scree slopes described webs and web building behaviour of several and in scree forests (Buchar and Ruûzˇicˇka, 2002). With a symphytognathoid spiders, including two mysmenids total body length of up to 1.1mm in adult females and (Mysmena sp. and Maymena sp.). Kropf (1990) de- 0.9mm in adult males (Thaler, 1975), T. granulum is scribed web construction in the species Comaroma si- among the small spiders of Central Europe. moni Bertkau, 1889 which belongs to the Anapidae. The species belongs to the Mysmenidae, which, along Symphytognathoid families include small to minute with the Anapidae, Symphytognathidae and Theridio- species, which build three-dimensional orb webs (Gris- somatidae, forms the group of symphytognathoid fami- wold et al., 1998; Schütt, 2003). The symphytognathoid lies (Coddington, 1990; Griswold et al., 1998), “sym- orb web is most probably a synapomorphy of the group phytognathoids” being part of the superfamily Arane- (Schütt, 2003). Egg sacs (“cocoons”) have never before oidea. Schütt (2003) regards Mysmenidae along with been studied in detail in any other species of the Mys- Anapidae, Micropholcommatidae and Symphytog- menidae and very little is known about the construction nathidae sensu strictu as part of the Symphytognathidae of cocoons by other symphytognathoids. Kropf (1997)
*Corresponding author: Jaromír Hajer, Department of Biology, University J.E. Purkinje, Cˇ eské mládezˇe 8, 400 96 Ústí nad Labem, Czech Republic; phone: ++420-475-601 309; fax: ++420-475-601 589; e-mail: [email protected]
0944-2006/03/106/03-223 $ 15.00/0 J. Hajer and D. Rˇ eháková gives a description of the egg sac structure in the of the spiders (Hajer, 2000). A high relative humidity species Comaroma simoni. (97Ð100%), also corresponding to the natural environ- Dragline silk is an extracellular fibrous protein called ment, was maintained by wrapping damp filter paper spidroin (Warner et al., 1999). Used by spiders to build around the outside of the Petri dishes. The dishes with web frames and to drop in controlled fashion from high spiders under observation were changed every 24 hours. places, it exhibits a unique combination of strength and This observation method was chosen, inter alia, due to toughness (Tirell, 1996). Anchored to the substratum Trogloneta granulum being not only a psychrophilic but by attachment discs, the “silk track” allows the spider also a photophobic species. Therefore, for the observa- to return safely to the starting point after a thrust at prey tion of living spiders it was necessary to use “cold light” or following a free fall; it also allows spiderlings to (circular fibre illuminator KVO). Video sequences of maintain contact with the parental web. The dragline the activity were copied on CD, and relevant pictures material is produced by a pair of major ampullate were printed on photographic paper. The photographs glands, while the material of attachment discs is se- showing movement of the spiders in detail during their creted by piriform glands (Foelix, 1996). Both types of spinning activity (and, therefore, not always perfectly glands are located at the surface of anterior lateral spin- focussed) were processed using an ACC (Adaptive nerets and have jet-like outlets called spigots. Contrast Control) Image Structure and Object Analyser. The research described in the present paper primarily This software was used to process Figs. 1Ð3 and 9. To focuses on the basic products of spinning activity, egg study the microstructure and ultrastructure of spidroin sacs and draglines, which, along with snares, are of crit- threads, we used an Eclipse E600 Nikon light micro- ical importance for the life of the studied spiders. Fol- scope equipped with a camera and a phase contrast fa- lowing up the latest study of the species (Hajer, 2000), cility, as well as a Tesla BS-340 scanning electron mi- we also researched the webs used for laying eggs. Be- croscope (Figs. 5, 7 and 8). Sections of a cocoon (Fig. 4) haviours associated with weaving the egg sac and using with embryos of Trogloneta granulum were made on draglines to handle the cocoon during development of day 5 of their embryonic development. For the process the eggs were observed. The results expand our knowl- of cutting with a microtome, the cocoon was inserted in edge of the family of Mysmenidae and may also be a piece of mouse liver. Sections (7 µ) were stained with used in analyses of phylogenes of the Araneoidea. hematoxylin and eosin. To study the ultrastructure of the threads forming the wall of the cocoon (Fig. 6), we em- ployed an AFM (Contact Atomic Force Microscope) Materials and methods METRIS 2001 (Burleigh Instruments Inc.).
All material studied was from the Vysoká Beˇta area in the Blansky« Les protected landscape area (South Bo- Results hemia, Czech Rep.). A total of 32 cocoons were ob- tained in the course of the research undertaken between Webs 1998 and 2002. Seven of these 32 egg sacs were col- lected at the above locality, while the other 25 were pro- Specimens of all nympho-imaginal stages of the onto- duced by 19 females kept under laboratory conditions. genetic cycle (except adult males) weave three-dimen- Most ethological observations were made from May 4, sional webs, resembling (if viewed from above) the 2001 to August 12, 2001. A video microscope equipped small orbs built by orb-weavers of the Araneidae. with a CCD camera was used during the study. The ma- Around the hub there are inner transverse threads which terial studied in this case consisted of 3 groups of 4 fer- connect all the radii and are continuously laid in the tilised females each, kept inside three Petri dishes form of concentric circles (Fig. 1). In completed webs, 100 mm in diameter and 15 mm high. Another 4 fe- more transverse peripheral threads are found distally males were kept separately in cubic glass boxes, made (Fig. 2B); however, these usually connect only two by glueing together the edges of four microscope glass (rarely three) neighbouring radii. With the exception of cover slips with dimensions of 22 × 22 mm. All contain- the hub, all components of the web are covered with ers were lined with black paper shaped so as to simulate droplets of a viscous secretion (Hajer, 2000). In gen- the uneven surface of stones. This arrangement gave the eral, the central part is oriented horizontally: so far, no spiders a place to hide and to spin their webs and co- web with a vertical hub has been observed. In the coons. At all times, one of the three Petri dishes was in- course of this study, the diameter of hubs woven by stalled under the video microscope, while the other two adult females varied from 0.5 to 1.0 mm (n = 27). In the were stored in a refrigerator at a temperature of centre of the web, spiders wait for prey. At the time of 9Ð11 ¡C. This temperature had been repeatedly mea- egg incubation, the same part of the web accommodates sured at the above-mentioned locality during collection egg sacs (Fig. 2 AÐB).
224 Zoology 106 (2003) 3 Spinning activity of Trogloneta
Egg sacs 3Ð5 eggs covered with viscous secretion on the ventral side of the spider’s opistosoma (i.e. immediately after During this study, the complete process of egg-laying leaving the gonopore); they did not continue with the and silk egg sac production (Fig. 3) was observed only construction of the cocoon. Having fled from the cen- five times. In the other three cases observed, the tral part the web, the female will shed the eggs, leaving females were interrupted by lightwhile there were them scattered throughout the web, and not revisit them. During egg laying, the female rests suspended on the threads of the central part of the web, with its dorsum downwards, as if waiting for prey (Fig. 3A). The hub is used in the same way as the orb-weavers’ platform but its threads are not incorporated into the egg sac wall. The female, suspended by the 1st and 4th pair of legs, rotates the mass of the eggs and, after the viscous se- cretion binding the eggs has hardened (Fig. 3B), the spider uses a few threads to attach the resulting egg batch to the lower side of the hub. The female then pro- duces a thin layer of silk to screen the eggs by moving its spinnerets, i.e. through direct contact with the eggs, covering a section of the batch (Fig. 3C). After tearing up some of the threads (Figs. 3DÐE), the spider rotates the batch somewhat and applies the substance to an- Fig. 1. An adult female Trogloneta granulum in the central part other section. While casting away torn-off threads, the of its web. Radial threads are continuously interconnected by female holds the cocoon using its palpi and chelicerae. inner transverse threads (TI) around the hub (H). The same procedure is repeated several times until the cocoon silk cover is completed. The female will sit by the finished cocoon in the central part of the web, with its dorsum upwards (Fig. 3F). The complete process of egg laying and egg sac construction takes 9Ð11 min- utes. Immediately after construction and during the next 5Ð6 hours, the cocoon is almost spherical, whitish (Fig. 2), 0.8Ð1.1 mm (n = 17) in diameter, with the silk wall remaining tight. However, the silk layer is very thin, and the eggs cause an uneven appearance of its surface. Each cocoon contains an average of 4.8 eggs (min. 3, max. 8, n = 26). Transverse sections (Fig. 4) revealed that there are no silk threads inside the co- coon, i.e. between the eggs. All threads in the cocoon wall have the same surface ultrastructure (Fig. 6), and the thickness of individual threads studied by the AFM ranged between 0.50 and 0.70 µm. One-week-old co- coons have an uneven shape, making it possible to count the number of eggs inside the cocoon by the number of tubercles. The spherical eggs averaged 0.19 mm in diameter (SE = 0.02, n = 20). At a constant temperature of 12Ð13 ¡C early development (from oviposition to emergence from the egg sac) takes 26Ð27 days. Spiderlings with body lengths of 0.20Ð0.22 mm (n = 22) leave the cocoon either through an opening made in the silk wall by the Fig. 2. Position of the egg sac in the central part of the web. (A) Side view. (B) Overall view (from above) of the web with an egg female‘s chelicerae, or through ruptures in the silk th th sac in its central part. ES, egg sac, RA, radial threads, TP, trans- wall (Fig. 5) which develop on the 13 to 15 day of verse peripheral threads. embryonal development.
Zoology 106 (2003) 3 225 J. Hajer and D. Rˇ eháková
Fig. 3. Six stages of egg sac production. (A) The hub, H(PL), serves as a platform, to which.the female holds while laying eggs. (BÐC) Using the 1st and 4th pair of legs, the female is suspended on the web threads; it uses the 2nd and 3rd pair of legs to rotate the batch of eggs. (DÐE)Tearing off the threads while the cocoon is being handled. The female uses its 1st right leg to draw closer one of the threads which fix the cocoon to the chelicerae, and tears it off (D). It holds the torn-off thread (marked with an arrow) for a fraction of a second, using its tarsal claws, and then casts it away (E). (F) Female spider with a completed egg sac (ES).
226 Zoology 106 (2003) 3 Spinning activity of Trogloneta
Draglines and attachment discs. Use of draglines in cocoon handling As a product of the secretion activity of a pair of major ampullate glands, the individual draglines of Trogloneta granulum consist of a pair of parallel fibrils (Fig. 7), just as in the case of other araneomorphs. Attachment discs are formed without involvement of the legs, i.e. by di- rect contact of the anterior lateral spinnerets with the substrate and rubbing against it. While rubbing, a thready secretion is exuded through the piriform glands’ spigots. In Trogloneta granulum, attachment discs are very simple (Fig. 7); they are produced by a single rub
Fig. 4. Section of a cocoon with embryos of Trogloneta granu- lum on day 5 of their embryonic development. Two of the four embryos (a1 and a2) are cut longitudinally, the other two (b1 and b2) transversely. The cut of embryo a1 is nearly a frontal Fig. 5. A detailed view of the cocoon surface. The age of the co- section, while the cut of embryo a2 is close to a sagittal section. coon is 21 days. At the end of the embryonic development the The wall of the cocoon, marked in (A) with white arrows, is wall of the egg sac develops ruptures in several places, which very thin and scantily spun. (B) shows that there are no silk gradually grow larger (one of them can be seen in the bottom threads inside the egg sac. LIV, tissue of mouse liver; Y, yolk; right-hand part of the picture as a small dark spot, marked with an ML, midline of the original germinal band, with marginal parts arrow) and are left unrepaired by the female. Thread bundles as in this embryonic stage laterally extended; Ceph, cephalic lobe visible in the upper left-hand part of the picture attach the egg sac of embryos. to surrounding objects.
Fig. 6. AFM image of the surface of the egg sac wall. The threads constituting the wall of the egg sac have the same ul- trastructure.
Zoology 106 (2003) 3 227 J. Hajer and D. Rˇ eháková
Fig. 7. The draglines always consist of a pair of stretched fibrils Fig. 8. Bundles of parallel threads are attached to the substrate (FI) which are, like all tight threads, attached to the ground by with accumulated attachment discs (AAT). means of attachment discs (AT). At a distance of several dozens of µm the two parallel fibrils are joined laterally to form one dragline. of the anterior lateral spinnerets against the substrate. Observations have shown two unusual methods of han- The discs are formed by a small amount of silk secre- dling the cocoon: shifting on ground surface, and transfer tion, due to a small number of piriform glands and spig- from the ground into a newly built web (Fig. 9). When ots (eight/six per spinneret in adult females/ males, shifting the cocoon on a firm surface (Fig. 9BÐF) the fe- resp.). However, as the spider moves along draglines, male first grips the cocoon with its two front pairs of legs doubling back to the points where attachment discs have (Figs. 9CÐD) and then moves it to the ventral side of its been placed, the lines grow thicker, forming bundles at- body. Subsequently, however, the female holds it by its tached to the substrate by a mass of piriform gland se- 3rd and 4th pair of legs at the end of the ventral side of its cretion (Fig. 8). In other words, there are two kinds of opistosoma so that the spider touches it with its spinning attachment discs: simple and accumulated ones. apparatus (Fig. 9E). While moving the cocoon this way, the spider touches the ground with two anterior pairs of legs only. If the female is disturbed in this activity, it Cocoon handling moves the cocoon under its prosoma and holds it under its The silk wall of the egg sac and the spinnerets are per- body using all its extremities. manently linked by means of a dragline. In six cases, We do not know how frequently Trogloneta granulum the female manipulated its cocoon carelessly, so that builds new webs when living in its natural habitat, and she was completely separated from the cocoon and the what the stimuli driving this activity are. Kept in the con- dragline was torn. In these cases the females abandoned fined space of Petri dishes under the conditions described the cocoon and stopped tending it. If cocoons were above, each of the 15 females kept in groups of three placed in their webs afterwards, the females invariably wove 5.4 webs on average (min. 4, max. 8) during the in- removed them. cubation period of 26Ð27 days. On the other hand, each of
Fig. 9. Handling of an egg sac using draglines or dragline bundles. (A) An egg sac (ES) attached by the female to the surface of the paper substratum and a newly built web (NW). (BÐC) Following completion of the web, the female returns to the cocoon, navigating by means of the draglines between cocoon and web. (DÐE) The female grips the cocoon with its two front pairs of legs (D) and moves it to the ventral side of its abdomen; afterwards it holds the cocoon with its 3rd and 4th pair of legs, while touching it with its spinning appara- tus (E). The female leans against the ground with the two front pairs of legs, shifting the egg sac to the edge of the substratum. (F) The female fixes the cocoon to the substratum with several short threads, anchored to the ground by attachment discs. (GÐJ) The process of connecting the cocoon and the hub by dragline bundles. The female leaves the attached cocoon, heading towards the web (G). As it moves, it draws the dragline (DL) behind itself (H). In the hub (I) (from which the radial threads (RA) radiate), it attaches the dragline (J) and heads off back to the cocoon, where it again attaches the new draglines. (K) The female tears off the threads which anchor the cocoon to the ground. (LÐM) The female holds to the loosened, catapulted cocoon with the 3rd and 4th pair of legs, while both the front pairs of legs (LE) are stretched in the direction of the movement. (N) The female immediately after catapulting (i.e. after landing) into the central part of the new web. (O) The female in a characteristic position of rest in the central part of a new web.
228 Zoology 106 (2003) 3 Zoology 106 (2003) 3 229 J. Hajer and D. Rˇ eháková the four females kept separately in cubic containers Webs of symphytognathoid families are characterised made of microscope glass cover slips built only two by Griswold et al. (1998) as being elaborate, highly webs during this period: one in which the female con- modified orb webs. These authors indicate several pos- structed a cocoon and another in which it stayed during sible synapomorphies. Following our previous observa- the development of the eggs. tions, we corroborate the following three: (1), loss of When moving the cocoon from one place to another, on wrap bite attack; (2), construction of three-dimensional the ground and into the central part of a new web (in a orb webs with anastomosed radii; and (3), addition of natural environment this process would take place un- hub loops after sticky spiral construction is complete. derground, i.e. in complete darkness), the following ac- Wrapping behaviour is not part of attacking the prey in tivities are repeated over and over again: (a) fastening T. granulum (see Hajer, 2000) and the behaviour dis- the cocoon to the substrate (Fig. 9F) by means of played by this species is very similar to the way of at- draglines and attachment discs; (b) linking the place tacking prey as described by Kropf (1990) in Comaroma where the cocoon is attached with the place where it is simoni (no wrapping behaviour, either). The phyloge- to be moved (Fig. 9GÐJ), using dragline bundles; this netic significance of anastomosis of radial threads prior journey between the centre of the web and the egg sac to insertion at the hub was stressed by Eberhard (1981). is repeated by the female 3Ð4 times. In this way, bun- Coddington (1986, 1990) and Griswold et al. (1998) dles of draglines are formed, which are attached both to consider this trait as a synapomorphy occurring in sym- the ground and the wall of the cocoon by means of ac- phytognathoid families. However, none of the studies cumulated attachment discs; (c) tearing the threads quoted offers an explanation for the origin of the anas- keeping the cocoon attached to the substrate (Fig. 9K); tomoses. While it is true that “anastomoses” can be ob- and (d) release of the cocoon and subsequent catapult- served in webs of T. granulum, they are created by ad- ing of the female to the central part of the new web, ditional thickening of radial threads with new draglines resulting from contraction of a bundle of draglines as the spider runs to and fro along the radial threads. (Fig. 9LÐN). The female tears the threads fixing the co- They are practically non-existent in newly made webs, coon to the ground by means of its chelicerae and most i.e. those observed shortly after completion. Webs of likely also by the enzymes contained in the fluid re- Trogloneta granulum always display the same elements leased from its mouth. The female holds to the loos- of construction, but their shape, their dimensions and ened, catapulted cocoon with the 3rd and 4th pair of legs, the arrangement of the individual components depend while the two anterior pairs of legs are stretched in the on the available space, the quality of the substrate, and direction of the movement (Fig. 9LÐM). Immediately the distances between the points at which the threads after landing, the female holds the egg sac in a similar can be anchored by attachment discs (Hajer, 2000). way as during the flight, i.e. with its 3rd and 4th pair of Information about symphytognathoids’ egg sacs avail- legs (Fig. 9N), at the same time touching the egg sac able to date is very limited; the egg sac of Comaroma with its spinnerets. Subsequently the female moves the simoni has been described by Kropf (1997). This author cocoon below its body and protects it in this position of reports that egg sacs were covered by a silken funnel of rest, with its dorsum upwards (Fig. 9O). The process, a slightly rose-red colour, which protects eggs against which occurs whenever the female builds a new web, predators and parasites. No study of mysmenid cocoons has been observed 16 times. The cocoon was never has been published. At the current state of research it is moved from the old web’s hub to the new by directly impossible to make a decisive assessment of the extent linking the two webs with threads, i.e. the cocoon was to which a scantily or economically woven egg sac is always placed on, and attached to, the surface of a solid characteristic of Mysmenidae, or whether it is one of substrate first. several reduction characters of these small spiders, which according to Schütt (2003), offer an ideal field to investigate the value and role of ‘reduction’ characters Conclusions in systematics. Comprehensive studies devoted to the evolution of orb-weaving spiders (Coddington, 1990, Trogloneta granulum builds a three-dimensional orb Griswold et al., 1998) consider a double attachment of web, which serves as a snare. In the case of females, the the egg sac to the substrate, i.e. egg sacs being attached hub of the web also serves as a platform for egg laying by two silk lines within the web or with one line at- and cocoon making. The shape of these webs, particu- tached to the substrate (Griswold et al., 1998), to be a larly their central part (i.e. the hub and inner transversal synapomorphy of the symphytognathoid families. Ac- threads laid continuously in the form of concentric cir- cording to Coddington (1990), plesiomorphic theridio- cles), supports the opinion of numerous arachnologists somatid genera such as Ogulnius, Plato, Naatlo, that these orb webs were derived from an orb web like Epeirotypus, the anapids Anapis, Anapisona, and the the one spun by spiders of the family of Araneidae. mysmenids Mysmena and Maymena retain their egg
230 Zoology 106 (2003) 3 Spinning activity of Trogloneta sacs at the hub of their webs and attach them at both ogy, Czech Academy of Sciences, Cˇ eské Budeˇjovice ends. However, Coddington adds a significant remark: for his willingness and unselfishness with which he “No one has ever seen a symphytognathoid egg sac in helped us to collect the studied material. We are espe- the field.” Trogloneta granulum does not exhibit any cially grateful to two anonymous reviewers for com- double attachment of egg sacs. ments that improved this manuscript. Draglines produced by Trogloneta granulum allow this species to move in the dark underground and to return to the web during attacks on prey; they also affect the References direction of movements of the female carrying its co- Buchar, J. and V. Ruûzˇicˇka. 2002. Catalogue of Spiders of the coon. The function of draglines as a means of moving Czech Republic. Peres, Praha. egg sacs, which is made possible by the excellent me- Coddington, J.A. 1986. The monophyletic origin of the orb web. chanical properties of spidroin, has not been described In: Spiders: Webs, Behavior, and Evolution (W.A. Shear, ed.). previously. Stanford University Press, California, pp. 319Ð363. Attachment discs (i.e. the hardened secretion of piri- Coddington, J.A. 1990. Ontogeny and homology in the male pal- pus of orb-weaving spiders and their relatives, with comments form glands) of most spiders of the suborder Araneo- on phylogeny (Araneoidea, Deinopoidea). Smithson. Contr. morpha have a thready microstructure (Schütt, 1996). Zool. 496: 1Ð52. In the case of T. granulum, however, they have the ap- Eberhard, W.G. 1981. Construction behavior and the distributions pearance (and function) of droplets of glue, which is of tensions in orb webs. Bull. Br. Arachnol. Soc. 5: 189Ð204. probably a result of miniaturisation of the spinning ap- Eberhard, W.G. 1987. Web-building behavior of anapid, symphy- tognathid and mysmenid spiders (Araneae). J. Arachnol. 14: paratus and a low number of piriform glands. 339Ð356. The results show the need for a thorough examination Foelix, R.F. 1996. Biology of Spiders. 2nd ed. Oxford University of the dragline-associated behaviour of spiders. Ac- Press, New York. cording to one of the theories on the original function of Griswold, C.E., J.A. Coddington, G. Hormiga and N. Scharff. spiders’ silk, known as the dragline theory (which is 1998. Phylogeny of the orb-web building spiders (Araneae, Orbiculariae: Deinopoidea, Araneoidea). Zool. J. Linn. Soc. rather neglected today), the dragline is the most original 123: 1Ð99. way of utilizing the spider silk (Savory, 1977). Of Hajer, J. 2000. The web of Trogloneta granulum Simon (Araneae, course, it is not consistently clear what the function of Mysmenidae). Bull. Br. Arachnol. Soc. 11: 334Ð338. the early dragline was. In our opinion, presumably one Kropf, C. 1990. Web construction and prey capture of Comaroma of the primary functions of draglines was to provide simoni Bertkau (Araneae). Acta Zool. Fenica 190: 229Ð233. Kropf, C. 1997. Egg sac structure and further biological observa- permanent contact with the cocoon and with the spider- tions in Comaroma simoni Bertkau (Araneae, Anapidae). Proc. lings included in it. Each of the roughly 32,000 de- 16th Europ. Coll. Arachnol., Siedlce 1996: 151Ð164. scribed species of Araneomorphae produce these essen- Platnick, N.I. 2003. The world spider catalog, version 3.5. Ameri- tial silk products, which have, undoubtedly, had a bear- can Museum of Natural History, online at
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