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Full text of ' 6?l, i A.b&B ENT 1 The Journal of VOLUME 23 1995 NUMBER 1 THE JOURNAL OF ARACHNOLOGY EDITOR: James W. Berry, Butler University ASSOCIATE EDITOR: Petra Sierwald, Field Museum EDITORIAL BOARD: A. Cady, Miami (Ohio) Univ.
At Middletown; J. Carrel, Univ. Coddington, National Mus. Natural Hist.; J.
Cokendolpher, Lubbock, Texas; F. Coyle, Western Carolina Univ.; C. Dondale, Agriculture Canada; W. Eberhard, Univ. Costa Rica; M.
Galia- no, Mus. Argentino de Ciencias Naturales; M. Greenstone, BCIRL, Columbia, Missouri; C.
Griswold, Calif. Horner, Midwestern State Univ.; D.
Jennings, Garland, Maine; V. Lee, California Acad. Levi, Harvard Univ.; E. Argentino de Ciencias Naturales; N. Plat- nick, American Mus.
Natural Hist.; G. Polis, Vanderbilt Univ.; S. Riechert, Univ. Tennessee; A. Rypstra, Miami Univ., Ohio; M. Robinson, U.S. National Zool.
Shear, Hampden-Sydney Coll.; G. Cincinnati; C. Valerio, Univ. The Journal of Arachnology (ISSN 0160-8202), a publication devoted to the study of Arachnida, is published three times each year by The American Arach- nological Society. Memberships (yearly): Membership is open to all those in- terested in Arachnida.
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Box 368, Lawrence, Kansas 66044 USA. THE AMERICAN ARACHNOLOGICAL SOCIETY PRESIDENT: James E. Carico (1993-1995), Dept, of Biology, Lynchburg, Vir- ginia, 24501 USA. PRESIDENT-ELECT: Matthew H.
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Stratton (1993-1995), Department of Biology, Albion College, Albion, Michigan 49224 USA. BUSINESS MANAGER: Robert Suter, Dept, of Biology, Vassar College, Pough- keepsie, New York 12601 USA. SECRETARY: Alan Cady (1993-1995), Dept, of Zoology, Miami Univ., Mid- dleton, Ohio 45042 USA. ARCHIVIST: Vincent D.
Roth, Box 136, Portal, Arizona 85632 USA. DIRECTORS: Allen R. Brady (1993-1995), Pat Miller (1993-1996), Ann Ryp- stra (1993-1995). HONORARY MEMBERS: C. Cover illustration: Scanning electron microscope photograph of the abdomen of a mature female Philoponella vicina (Uloboridae). Photograph by Flory Pereira and William G.
Publication date: 9 August 1995 ® This paper meets the requirements of ANSI/NISO Z (Permanence of Paper). The Journal of Arachnology 23:1-8 PHILOPONELLA REPUBLICANA (ARANEAE, ULOBORIDAE) AS A COMMENSAL IN THE WEBS OF OTHER SPIDERS Ann L. Rypstra and Greta J. Rinford 1: Department of Zoology, Miami University, 1601 Peck Blvd., Hamilton, Ohio 45011 USA ABSTRACT.
Juvenile individuals of the spider species, Philoponella republicana, were common in the webs of the social spider, Anelosimus eximius, and the solitary spider, Architis sp., in the forest habitats of the SE Peru. The abundance, size and location of P. Republicana individuals were surveyed in each host web. Although the host webs were similar in size and conformation, more P. Republicana individuals were found in the social spider webs than in the solitary host webs. Likewise, the number of P. Republicana in the social spider webs was correlated with host web size.
The mean size of prey captured by P. Republicana was 2.1 mm, which was significantly smaller than the prey taken by the social spider, and, in feeding trials, Architis sp. Individuals reacted only infrequently to prey of that size. This separation in the size of prey taken caused us to conclude that P. Republicana acted as a commensal for the most part; however, they were observed to prey on the social spiders occasionally. Republicana were the most common in both host webs and tended to be high in the barrier webbing.
The largest individuals in the social host webs were located under the sheet area, and these individuals were observed to feed more frequently than spiders in other size classes and in other areas of the host webs. We conclude that juvenile P. Republicana are commensals in both host webs but that they benefit more from the greater amount of activity in webs Mounting evidence from phylogenetically di- verse species shows that grouping behavior may simultaneously reduce individual risk of preda- tion and enhance feeding efficiency (Pulliam & Caraco 1984; Uetz 1988; Uetz & Heiber 1994).
Heterospecific interactions within social groups can bring advantages to individuals in those groups that do not accrue to individuals in single species aggregations (Morse 1970; Barnard & Thompson 1985). Slightly different foraging modes and food preferences may lead to more efficient resource usage by mixed species groups which can simultaneously take advantage of oth- er kinds of advantages of being in a group. A wide variety of heterospecific relationships have been reported among spider species ranging from predation (Larcher & Wise 1985; Jackson & Whitehouse 1986; Jackson 1990) to klepto- parasitism (Vollrath 1987; Cangialosi 1990), to commensalism (Rypstra 1979; Bradoo 1986, 1989). In many of these instances, host spiders have large complex webs that can provide a liv- ing space with some support and protection for the second spider species (Rypstra 1979; Bradoo 1986, 1989; Hodge & Uetz 1992). In particular, the webs of communal or social spiders tend to provide habitat for other spider species who in- 1 Present address: Dept, of Ecology and Evolutionary 1 USA social spiders.
Teract with the host in both positive and negative ways (Rypstra 1979; Bradoo 1989; Cangialosi 1991; Hodge & Uetz 1992). A commensal association occurs when one species reaps some benefits by association with a host species but the host species is essentially unaffected, positively or negatively, by the as- sociation. Commensalism has been reported with some frequency among spider species in the fam- ily Uloboridae (Struhsaker 1969; Opell 1979; Bradoo 1986; 1989). Bradoo (1989) concludes that Uloborus ferokus Bradoo (Araneae, Ulobor- idae), living in the webs of the social spider Ste- godyphus sarasinorum Karsch (Araneae, Erisi- dae), receives protection, support and increased prey capture which increases its lifespan and fit- ness. The spider species, Philoponella republi- cana (Simon) (Araneae, Uloboridae), is frequent- ly found in single species aggregations (Smith 1985; Binford & Rypstra 1992); but, in addition, we have found immature individuals of the spe- cies in the interstices of the webs of almost all complex, semi-permanent spider webs at our study area in SE Peru. Republicana were par- ticularly common in the webs of Anelosimus ex- imius Simon (Araneae, Theridiidae), a cooper- atively social species in this area.
The goal of this logy, University of Arizona, Tucson, Arizona 85721 1 2 THE JOURNAL OF ARACHNOLOGY study is to describe the abundance and distri- bution of P. Republicana in the large webs of this social spider in comparison with its distribution in the webs of a solitary species, Architis sp.
(Ara- neae, Pisauridae), whose web is of similar size and structure (Nentwig 1985). METHODS Data were collected on spider populations in- habiting the subtropical moist forest of the Tam- bopata Reserved Zone, 35 km southwest of Puer- to Maldonado in Madre de Dios, Peru.
Data were collected in the dry season: July and early August of 1987, 1988 and 1989 (see Erwin 1985 for complete description of the habitats). The webs of both host spiders were very sim- ilar in overall appearance. They consisted of a dense sheet of webbing subtended by a maze of barrier webbing encompassing neighboring veg- etation (Brach 1975; Christenson 1984; Nentwig 1985). Eximius is a cooperatively social species so each web contained several hundred to several thousand individuals that worked together to capture prey (Brach 1975; Christenson 1984). Is a solitary spider and a single in- dividual monitors insects arriving in the web from a funnel-shaped retreat at one end of the sheet area of the web (Nentwig 1985).
Eximius are 4-6 mm in length, which is substan- tially smaller than Architis adults which are 8- 12 mm in length. Surveys were conducted of all A. Eximius webs found, a total of 46 webs, between 4 July and 4 August in 1987 (18 webs), 1988 (16 webs) and 1989 (12 webs). To avoid the confounding factor of repeated measures only one survey per social spider web was included in the data set. In order to standardize for season and temperature across the years we selected the first survey conducted on a web after 4 July on a dry day on which the temperature was between 24-28 °C.
A total of 12 Architis sp. Webs were surveyed a single time and under similar weather circumstances in July of 1 989. During each survey, P. Republicana were classified into three size categories: large (4-6 mm in length), medium (2-4 mm in length), and small (less than 2 mm in length). Republicana were also categorized by position in the host web. That categorization included spiders located un- der the sheet, just above the sheet (within 2 cm), in the low barrier of the web (2-20 cm above the sheet) and in the high barrier (20 cm or more above the sheet). In order to obtain one measure of site quality within the host web, we also attempted to de- termine the feeding frequency of P.
Republicana spiders located in different positions. A spherical bundle in the chelicerae of the spider was evi- dence that it had captured a prey item recently. One complication that arises in determining the likelihood of feeding is that the spider will feed longer on large prey than on small prey so a survey sampling technique would have biased the results toward large prey. In the case of A. Eximius webs, we typically spent two or more hours observing so, for this study, we only count- ed the prey items that were captured during our observation times. For Architis webs, we sur- veyed a second time 2-3 hours after the first observation to estimate a feeding rate in a similar fashion.
Solomat Mpm 500e Manual Meat Grinder
To determine whether the two species were actively competing for prey that entered the web or if there was a division of resources based on prey size, we needed to determine the range of prey sizes taken by each of the host species. The distribution and frequency of prey capture were obtained for A. Eximius in the course of a si- multaneous study (Rypstra 1990; Rypstra & Tir- ey 1991). In order to determine whether the sol- itary Architis sp. Actively preys on insects in the size class that P.
Republicana handles, we con- ducted a feeding experiment. Field-caught fruit flies (. Drosophila spp. 5-2.0 mm in length, the mean size of prey taken by P.
Republicana) were gently blown into each of ten webs of Architis. In all cases the Architis individual was at the opening of its retreat in a feeding position at the time the prey were introduced. If the Architis spider retreated before the prey was in the web or if it was apparent that we had disturbed her in the process, no data were taken.
If we suc- cessfully introduced the fly without disturbing the host spider and we were able to detect that the fly contacted the sheet in a way sufficient to vibrate the threads, we recorded the reactions of the Architis. Between 8-12 flies were tested in each of ten Architis webs. After each trial, a larger fly or grasshopper was introduced into the web to see if the host spider was receptive to any prey. If we could not get the spider to respond, the results of the trial were excluded from the anal- ysis.
RESULTS All of the webs that we found in all three years had some P. Republicana in them. On average, there were 8.4 ±3.3 (mean ± standard deviation) RYPSTRA & BINFORD-SPIDER COMMENSALS 3 1987 1988 1989 ARCHITIS WEB DIMENSION (CM) Figure I.—- The number of commensal Philoponella republicana individuals vs.
The longest horizontal dimen- sion of the host web. Data points indicated for the three years (1987, 1988, and 1989) are all for the social host, Anelosimus eximius. Data for the solitary host, Architis sp., were all gathered in 1989. The correlation between web size and number of commensals is significant for the social Anelosimus eximius but is not significant for the solitary Architis sp. Republicana individuals in the 46 A.
Eximius webs we surveyed over three years. There were no differences among the years (Kruskal- Wallis Multiple Comparisons, P 0.05). There were significant positive relationships between social spider web size and the number of P.
Republicana in the web both within each year and when the data for all years were pooled. The strongest re- lationship was between the longest horizontal di- mension and number of spiders (for all years together: Spearman’s r = 0.85, P 0.25). However, there was no relation- ship between web size and number of P. Repub- licana individuals in Architis sp. Webs (longest horizontal web dimension and spider number: r = 0.4, P 0.2) (Fig.
The distribution of P. Republicana individuals in the various size classes we identified was not even within either host web (x 2 Test, P 0.3) (Fig.
Medium-sized P. Repuhlicana were evenly distributed across the positions within the social spider webs (x 2 Test, P 0.3); however, those located close to the sheet were more likely to be observed feeding than those in the barrier areas (25 of the 30 spiders that captured prey) (Fig. Forty-seven of the 77 large spiders we observed were located under the sheet of the host web so the distribution of individuals in this size class was not even across the positions (x 2 Test, P 15 cm), more or less horizontal leaves. The upper portion of the web was a tangle of non-sticky lines attached to the underside of the leaf. The lines of the mesh were more closely spaced in the area where the spider rested during the day against the underside of the leaf. The spider’s pale green color and its elongate abdomen, which it laid flat against the leaf, made it extremely cryptic.
Egg sacs had thin walls with projecting processes, and the sphere of pale green eggs was plainly visible inside. The sacs (up to four per female) were suspended in the mesh under the leaf. The approximately planar prey capture web, strung vertically below the mesh, varied to some extent (Fig. The lateral edges of the capture web were formed by two long, more or less ver- tical, non-sticky “frame” lines. The interior por- tions contained more or less regularly spaced lines, most of which had many short (0.2-0. 5 cm) seg- ments of adhesive on them. Initiation of capture web construction was not observed.
Judging both by the lines present in the webs when first observed, and by the order in which subsequent lines were laid, it is probable that the first lines laid were the approximately vertical frame lines. One spider with only a mesh descended twice at the end of her dragline as if to begin construction early in the evening, but failed to contact a substrate below and climbed back up without making an attachment (and later abandoned the website). Subsequent lines were added in a highly ste- reotyped order (Fig.
The spider began by at- taching a dry line at the top of the capture web, usually near one edge. She then walked down- ward along the innermost line already present (this was the frame line in the first descent, and a line with adhesive segments in subsequent de- scents), attaching the non-sticky dragline she was laying periodically to the line along which she was walking (Fig. Immediately after each of these attachments, the spider backed up a short distance along the dragline and attached her dragline to it (Fig. 2A), thus making a short, more or less horizontal line (a “rung”), and then con- tinued her descent. In one case the spider broke and replaced the distal portion of the frame line along which she was walking as she neared the bottom of the capture web. After making the lowermost attachment to the line along which she was descending, the spider turned and began to climb the line she had just laid.
She broke this line soon after she turned, and began reeling it up, replacing it with a new “sticky” line which consisted of a non-sticky line with evenly spaced short segments of sticky ma- terial. Each sticky segment was produced as both legs IV held the dragline and appeared to pull a short length from the spinnerets; the spider took one step forward with each leg IV (thus drawing out further silk), and then laid another sticky segment. Each time she reached a rung line, the spider broke it and performed a quick series of movements which I was unable to decipher, and then continued her upward climb. Judging by the pattern of lines when she was finished (Fig.
2B), probably the spider attached her dragline to the broken end of the rung line, paid out a short length of silk, and then attached her dragline to this line. A short segment of doubled line may have thus been produced, in a manner similar to the doubled lines laid during the descent (steps 2 and 3, and 4 and 5 in Fig. Each finished rung had a single spot of white near the middle, apparently corresponding to the broken end of the line to which the spider had attached her dragline. In one web the spider alternated descents on the right and then the left side of the web.
In another web she made several descents on one side (the larger of the two) before making any on the other. In both webs later lines with sticky material were progressively less vertical, as the spider filled in the central portion of the web (Fig. The final line was made following construc- tion of the lowermost sticky line.
The spider moved more or less directly upward through the middle of the capture web to the mesh above, laying a sticky line as she went. In one web the spider clearly broke all of the lines she encoun- tered as she climbed, reattaching each to the sticky line she was laying. A short length of silk was paid out just before each reattachment, thus low- ering the tension on these lines.
DISCUSSION Although the prey capture webs of S. Ecu- adorensis are different from those of S. Turbinatus and S. (compare Figs. 1 and 2 with Fig. 3), EBERH ARD — WEB OF SYNOTAXUS ECUADORENSIS 27 Figure 1.— Two newly-built capture webs of mature female Synotaxus ecuadorensis coated with cornstarch.
The spider is just visible at the top of the upper web. In the lower web the lines at the right and the curved line from the tip of the leaf at the left are out of the plane of the capture web (scale lines = 5.0 and 6.0 cm for upper and lower webs).
—Diagrammatic representation of the probable order of operations by Synotaxus ecuadorensis build- ing a prey capture web. Thicker lines and large dots indicate the lines and attachments made during the period represented by each drawing; wiggly lines represent patches of adhesive; and numbers refer to the order of attachments. The spider starts from the mesh under the leaf along one of the two long non-sticky, more or less vertical lines that form the lateral borders of the web, laying a non-sticky dragline. Periodically she attaches the dragline to the frame (e. G., 2, 4), and backs up slightly and attaches to the line just laid (e. G., 3, 5) forming a “rung”.
She then continues downward to make a final attachment to the frame (e. Turning back immediately, the spider breaks the line she has just laid, attaches her trail line to the broken end (7), and begins laying another line with sticky patches on it as she climbs back up along the line she just laid.
She breaks each rung and attaches her dragline to the broken end (e. Backing up slightly, she attaches to the line she just laid (e. G., 9) and continues upward, finally attaching the sticky line to the mesh near where she started (12).
Subsequent lines are laid on the same or the opposite side of the web with a similar series of movements. Sticky lines laid later are progressively less vertical. The attachments 9 and 12 were deduced from the positions of lines in finished webs, while all others, and the breaking of lines at 7, 8 and 10 were confirmed by direct observations. Several details indicate that the prey capture web of S. Ecuadorensis is homologous with a single “unit” of the web design of the others (Eberhard 1977) (Fig.
Both types of web are initiated with a pair of long, more or less vertical, straight, non-sticky lines which form their lateral margins. A complex sequence of behavior follows, in which construction of non-sticky and sticky lines alter- nate, with the sticky lines bearing widely spaced segments or dots of adhesive.
One detail of this process in all three species is apparently unique to Synotaxus among all araneoid web builders studied to date: after attaching its dragline to another line, the spider backs up a short distance and makes another attachment to the line it just laid, then continues onward (e. A further similarity is that sticky lines are laid as the spider climbs upward, each replacing a non-sticky line laid during an immediately pre- ceding descent. Construction ends with place- ment of a central sticky line laid as the spider ascends. Lines already present are apparently EBERHARD- WEB OF SYNOTAXUS ECUADORENSIS 29 Figure 3. —Tentative order of operations in the construction of a unit web of Synotaxus turbinatus (after Eberhard 1977).
The spider moves from side to side as she descends, laying both sticky and non-sticky lines (A, B, C). After reaching the bottom (D), she climbs up the middle of the web, replacing the non-sticky line with a sticky line (E). Broken and reattached to this central line. Both types of webs are vertical, more or less planar, and relatively fragile arrays that are rebuilt daily, and are located immediately below a more per- manent mesh of non-sticky lines near the un- derside of a large leaf where the spider rests. These proposed homologies must remain ten- tative, however, until further data on Synotaxus and related genera become available. The ap- parent homology of the S. Ecuadorensis web to a unit of the webs of other Synotaxus species indicates that the “units” of these species are not simply abstractions, but that web construction may be also organized in the spider’s nervous system as units.
Differences between the webs and construction behavior of S. Ecuadorensis and that of other Synotaxus are also substantial.
They include the following: the web is constructed as a single unit, with only a single pair of vertical frame lines rather than as a series of modules; a long, un- interrupted non-sticky line is laid during each descent and is nearly completely removed during the ensuing ascent; placement of adhesive ma- terial is in short segments rather than single balls on the sticky lines; and there is no non-sticky “frame” line at the bottom of the web (also some- times lacking in other Synotaxus). The construction behavior of S. Ecuadorensis is to my knowledge the clearest described ex- 30 THE JOURNAL OF ARACHNOLOGY ample in which a spider does not organize its activities around a central area. Instead, after establishing three sides of the planar web (the mesh above and the two lateral frames), the spi- der moves back and forth across the fourth side, gradually extending the web in a process analo- gous to crocheting. I have seen a similar process only one other spider (a species of the theridiid Chrosiothes which repairs holes in its sheet in this manner) (Eberhard, pers.
ACKNOWLEDGMENTS My trip to La Planada was financed by the Fundacion para la Educacion Superior; the staff at La Planada helped make my stay pleasant and productive. Carlos Valderrama kindly collected voucher males. Levi kindly identified spiders, and R.
Gillespie and B. Opell made helpful comments on a preliminary manuscript. My research was supported by the Smithsonian Tropical Research Institute and the Vicerrectoria de Investigation of the Universidad de Costa Rica. I thank all for their help.
LITERATURE CITED Comstock, J. The Spider Book (revised and edited by W.
Cornell Univ. Press, Ith- aca. “Rectangular orb” webs of Synotaxus (Araneae: Theridiidae). Hist., 11: 501-507. Construction behavior of non-orb weaving cribellate spiders and the evolu- tionary origin of orb webs.
Solomat Mpm 500e Manual Meat Maker
British Arachnol. Soc., 7:175-178.
Combing and sticky silk at- tachment behaviour by cribellate spiders and its tax- onomic implications. British Arachnol. Soc., 7:247-251. Early stages of orb construc- tion by Philoponella vicina, Leucauge mariana, and Nephila clavipes (Araneae, Uloboridae and Tetrag- nathidae), and their phylogenetic implications. Arachnol., 18:205-234. Web construction by Mod- isimus sp. (Araneae, Pholcidae).
Arachnol., 20: 25-34. Behavior and ecology of four species of Modisimus and Ble- chroscelis (Pholcidae). Arachnol., 6:29-36. & Montenegro, E.
Formaciones vegetales de Colombia. Republica de Colombia, In- stitute Augustin Codazzi, Bogota.
Platnick, & J. Codding- ton. A proposal and review of the spider family Synotaxidae (Araneae, Araneoidea), with notes on theridiid interrelationships. Ameri- can Mus. On the nest and web structure of Latrodectus in South Africa, and some observa- tions on body colouration of L. Geometricus (Ara- neae: Theridiidae).
Natal Mus., 20:1-14. The web-spinning process and web- structure of Latrodectus trecinguttatus, L. Adobe editor free download.
Pallidus and L. London, 145:75- 89.
Evolution of the web spinning ac- tivities: the web spinning in Titanoeca albomaculata Luc. (Araneae, Amaurobiidae). Manuscript received 25 July 1994, revised 14 November 1994. The Journal of Arachnology 23:31-36 LOS NERVIOS OPTICOS EN CUATRO ESPECIES DE LACTRODECTUS (ARANEAE, THERIDIIDAE) Carmen J.
De la Serna de Esteban y C. Monica Spinel!!: Facultad de Ciencias Exactas y Maturates, Universidad de Buenos Aires, Departamento de Ciencias Biologicas. Ciudad Universitaria Pabellon II 4 Piso Lab, 22- (1428) Buenos Aires, Argentina ABSTRACT. The pathway of the optic nerves in the studied species of Latrodectus shows intraspecific vari- ation. Dilatations, empty or containing a pigment of unknown function, can be seen in the nerves. Curiously, this pigment originates in the retinal cells.
The optic nerves ran through the prosoma and merge, forming two or four optic centers, which are finally joined into a single one. La trayectoria de los nervios opticos en las especies de Latrodectus estudiadas muestra variation intraespecifica. En ellos existen dilataciones que pueden hallarse vacias o conteniendo un pigmento originado en las celulas retinianas, cuya funcion es desconocida. Estos nervios forman dos o cuatro centros opticos que luego se fusionan en un centro unico. El trayecto de los nervios opticos en el pro- soma de varias especies de Tegenaria Latreille 1804 fue estudiado por Legendre (1959), quien sin determinar el ordenamiento de los mismos confirm© que este genero caretia de quiasma op- tico. Este autor dice que los nervios opticos sur- gen de la superficie anterior del ganglio cere- broide, hallandose constituido cada uno de ellos por tres haces de fibras, los que se dirigen a los ojos laterales, y por encima de los cuales se en- cuentra un pequeno haz impar. El mismo autor, hallo estas mismas particularidades con mmimas variaciones en especies que no cita en el trabajo, asi como tampoco las familias sobre las que rea- lize el estudio.
Homann (1947) considera que en la arana se- dentaria Araneus sexpunctatus, los nervios op- ticos penetran en conjunto en el ganglio cere- broide, originandose asi un centro optico unico. Baccetti y Bedini (1964) realizaron estudios mediante microscopia optica y electronica en los ojos de Arctosa variana (Lycosidae), en los que senalan la presencia de un pigmento claro en los nervios opticos, sin especificar origen ni natur- aleza quimica del mismo. En el presente trabajo se estudio el recorrido de los nervios opticos en el prosoma, en cuatro especies del genero Latrodectus (Araneae, Ther- idiidae) obteniendose resultados que no coinci- den con las observaeiones realizadas para otras especies, por los mencionados autores. Por otra parte el llamativo recorrido de los nervios opticos, con variaciones intraespecificas condujo a realizar un estudio comparative de los mismos. METODOS Se emplearon 1 1 ejemplares del genero Latro- dectus: dos individuos de L.
Geometricus Koch 1841, dos de L. Mirahilis Holmberg 1 876, cuatro de L. Antheratus Badcock 1932 y tres de L. Cor- allinus Abalos 1953. Los fij adores utilizados fueron: formol 10%, Helly y Bouin y la inclusion se realizo en para fina.
Las coloraciones histologicas de rutina fu- eron: Hematoxilina de Carazzi - Ponceau de Xil- idina - Azul de Anilina, Mallory - Heidenhain (Azan), fucsina paraldehida segun Gabe (Martoja y Martoja Pierson). Las coloraciones histoqmmi- cas fueron: Periodic Acid SchifF (P. S), color- ation para prottinas segun Martoja y Alcian Blue a diferentes pH. Para la indentificacion de los nervios opticos correspondientes a cada ojo, en su trayectoria, se confeccionaron esquemas rotulandose los ner- vios con las siguientes abreviaturas: OMA: ojo medio anterior; OLA: ojo lateral anterior; OMP: ojo medio posterior; y OLP: ojo lateral posterior. Dado que los nervios se fusionan de a pares a corta distancia de su emergencia del ojo, se ha empleado la siguiente denomination, nj = OMA derecho + OLA dereeho; n 2 = OMA izquierdo 31 32 THE JOURNAL OF ARACHNOLOGY Figuras 1-5.— Nervios en especies de Latrodectus.