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Predator diets represent a potential interaction between local prey availability, prey antipredator defenses, and predator foraging behavior. Female spider-specialist mud-dauber wasps (Hymenoptera: Sphecidae) collect spiders and provision them intact, but paralyzed, to their developing larvae, providing a unique means of quantifying the diversity and abundance of prey that they capture. Mud-dauber wasps are hypothesized to be a major source of selection on antipredator defenses in web-building spiders, and the spiny and thickened abdomens of female spiny orb-weaving spiders (Araneae: Araneidae) are hypothesized to function as antiwasp defenses. We inventoried spider prey from nests of the mud-dauber wasps Sceliphron caementarium (Drury) and Chalybion californicum (Saussure), and surveyed for spider fauna in areas surrounding nest collection sites, to specifically investigate if the spiny orb-weaver Micrathena gracilis (Walckenaer) was collected as prey by these wasps. We collected nests from six sites in southeastern Nebraska from two regions that we classify based on habitat—a forest corridor and agricultural land. We collected 761 intact spider prey from 87 nests and identified them to the family level. None of these spiders were M. gracilis. Micrathena gracilis were rare in faunal surveys on agricultural land and, surprisingly, absent in forest corridor surveys. Mud-dauber wasps were more common; we collected more spiders on agricultural land than in the forest corridor. We propose that in agricultural landscapes, the lack of certain spiders in mud-dauber wasp nests is driven by habitat use differences between predators and prey rather than physical antipredator defenses.

The observable diversity of antipredator defences across organisms demonstrates predation's impact on trait evolution. The functions of many traits that are presumed to have an antipredator function have never been directly tested. The spiny orb-weaving spider, Micrathena gracilis, for example, stridulates when grasped. While stridulation was first hypothesized to be an antipredator defence nearly 50 years ago, no data exist to support this hypothesis. To explore the form and function of M. gracilis stridulation, we first quantified the behavioural and acoustical properties of sound production. Next, using laboratory assays, we directly tested the effect of stridulation on survival with an avian predator – blue jays, Cyanocitta cristata. Finally, we conducted a large mark–recapture field study in which we compared the natural survival of experimentally manipulated adult female M. gracilis that could not stridulate (silenced) versus could stridulate (control). Stridulatory pulses produced broadband frequency spectra, consistent with acoustic antipredator defences in other taxa. We also observed stridulation by male M. gracilis for the first time. In staged laboratory interactions with captive blue jays, we found no differences in survival between silenced and control M. gracilis. Similarly, in our mark–recapture field study, we found no differences in survival estimates between silenced and control groups, nor an effect of stridulation rate. While M. gracilis stridulation closely resembles antipredator stridulation in other arthropods, our behavioural data do not yet provide solid support for an antipredator function in M. gracilis.

Behavioural adjustments to changing environmental conditions are advantageous for spiders, as such adjustments likely allow spiders to remain in good hunting sites. Here, we describe the behavioural response of seven araneoid species to heavy rain in the neotropics. Five of the seven spiders drastically modified their position on the web, relative to the typical resting position. Four of these species (Allocyclosa bifurca, Argiope argentata, Cyrtophora citricola, and Leucauge mariana) hung from hub threads using their legs III and IV, oriented the anterior section of the prosoma downward, and moved legs I and II forward in front of the spider's eyes. Trichonephila clavipes had a similar response, but hung from only its legs IV. Two other species (Gasteracantha cancriformis and Micrathena duodecimspinosa) did not show an apparent response to heavy rain. The change in position reduces the spider's surface that heavy rain could impact, and speeds water drainage which may reduce pathogen infection. Universidad de Costa Rica/[833-C0-251]/UCR/Costa Rica UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biología UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Biodiversidad y Ecología Tropical (CIBET)

Before constructing an orb web, an araneoid spider takes down and ingests the previous day's web. Nocturnal species do this either during the early evening or in the early morning and diurnal species during the early morning, times of the day when relative humidity (RH) is high. Under these conditions the hygroscopic glue droplets of a web's viscous prey capture thread attract atmospheric moisture, providing a net gain of water when a spider ingests its web. The contribution of web recycling to a spider's water budget has been estimated, but not determined empirically. This study does so for adult females of four species (Araneus marmoreus Clerck, 1757, Argiope trifasciata (Forskal, 1775), Leucauge venusta (Walckenaer, 1841), and Micrathena gracilis (Walckenaer, 1805)) by first determining the total volume of a web's glue droplets at 20% and 37% RH to estimate the water invested in web during construction. Subtracting each of these values from the web's total droplet volume at 90% RH approximates the range of water harvested when the web is recycled. High estimates of the net water gained range from 0.45% of a spider's body mass (3.01 µl water gained) in A. marmoreus to 0.88% of body mass (0.19 µl water gained) in L. venusta. In A. trifasciata, the water gained when a web is ingested is equivalent to 29% of a spider's daily evaporative water loss.

Extended phenotypes are traits that exist outside the physical body of the organism. Despite their potential role in the lives of both the organisms that express them and other organisms that can be influenced by extended phenotypes, the consistency and covariance with morphological and behaviour traits of extended phenotypes is rarely evaluated, especially in wild organisms. We repeatedly measured an extended phenotype that directly influences an organism’s prey acquisition, the web structure, of wild orb-weaving spiders (Micrathena vigorsii), which re-build their webs each day. We related web structure traits to behavioural traits and body size (length). Both web diameter and web density were repeatably different among individuals, while reaction to a predation threat was slightly so, but response to a prey stimulus and web symmetry were not. There was a syndrome between morphology and web structure traits, where larger spiders spun webs that were wider, had webs with increased thread spacing, and the spider tended to react more slowly to a predation threat. When a spider built a relatively larger web it was also relatively a less dense and less symmetrical web. The repeatability of web construction and relationship with spider body size we found may be common features of intra-population variation in web structure in spiders. Individual variation along the morphology and web structure syndrome could represent variation in individual foraging strategies, or age-based correlated changes. By estimating the consistency and covariances of extended phenotypes we can begin to evaluate what maintains their variation and how they might evolve.

Araneid orb weavers systematically weaken the radii in their orbs by partially or completely removing the provisional radial lines laid during radius construction. Removal of provisional radii by Micrathena duodecimspinosa (O. Pickard-Cambridge, 1890) tended to be less complete for those radii that were attached later during the radius construction stage to the same frame line; this pattern differed from previous observations of provisional radius removal in two other araneids. Patterns of removal in M. duodecimspinosa were not in accord with a previous hypothesis that provisional radius removal functions to adjust radial tensions. In addition, M. duodecimspinosa moved in complex, jerky paths during radius construction that did not occur in previous or subsequent stages of construction. These movements resulted from the spider vibrating the entire web as she moved; their functional significance is unclear.

In this study, 10 nominal species of Eustala Simon, 1895 are synonymized with other species of the genus, mostly based on matching males and females erroneously described as different species. Parawixia rimosa (Keyserling, 1892) is considered a senior synonym of Eustala decemtuberculata Caporiacco, 1955. Eustala isosceles Mello-Leitão, 1939 is transferred to Kapogea Levi, 1997 and considered a senior synonym of Kapogea alayoi (Archer, 1958) based on abdomen shape and coloration. Micrathena beta Caporiacco, 1947 is redescribed, illustrated and transferred from Linyphiidae back to Araneidae. This species can be easily distinguished from other members of the genus by the male palpus with an enlarged and modified paracymbium and a narrower hook as a conductor. Micrathena sanctispiritus Brignoli, 1983 is removed from the synonymy with M. lindenbergi Mello-Leitão, 1940 and considered a senior synonym of M. guanabara Levi, 1985.

The function of silk web decorations in orb weaving spiders has been debated for decades. The most accepted hypothesized functions are that web decorations 1) provide camouflage against predators, 2) are an advertisement for vertebrates to avoid web damage, or 3) increase the attraction of prey to the web. Most studies have focused on only a few genera, Argiope being the most common. In this study, I evaluated the prey attraction hypothesis of silk decorations for a species of a poorly studied genus in this topic, Micrathena sexpinosa Hahn 1822. I used a web-choice experiment in which I presented empty or web-bearing frames at the end of a tunnel to stingless bees (Tetragonisca angustula). This frame-choice experiment consisted of the following comparisons: decorated web vs. empty frame, decorated web vs. undecorated web, and undecorated web vs. empty frame. Webs with decoration intercepted significantly more bees than empty frames and undecorated webs. Therefore, the decorations of Micrathena sexpinosa might play a role in increasing foraging success.

Polymorphism, a phenomenon which is important for speciation, can be found in wide range in species. Conspicuous colour and pattern polymorphisms are widely observed among spiders, including the spiny backed spiders (Gasteracantha spp., Micrathena spp. and Thelacantha spp.), which belong to the family Araneidae. These spiders are described as „spiny backed‟ because of the presence of prominent spines on their abdomen. Thelacantha brevispina is often mistaken as crab spider. They are a scientifically less known spider species and have been categorised as an endangered species in Sri Lanka according to the Red List of 2012. The present study aims to characterise the polymorphism among theses spiders in Northern Sri Lanka. The samples, the exuviae and dead female spiders were collected from the islands and mangroves in and around the Jaffna Peninsula. The museum specimens deposited in the zoology museum at the University of Jaffna were also used in the analysis. Two different pattern morphs were observed. Morph A has the round shaped white marking on the middle of the carapace and morph B has half-moon like white markings on the carapace. Length, width and distance between spines were measured for the statistical analysis using a venire scale (least count 0.1 mm). Morph A is relatively bigger than morph B with the average length of 11.8 mm and average width of 4.0 mm. Morph B has an average length of 6.7 mm and average width of 4.6 mm. The measured lengths and widths were significantly different (p

A new species, Micrathena cicuta, is described and illustrated based on females from southeastern Brazil. Plectana degeeri Walckenaer is synonymized with M. plana (C.L. Koch), based upon the original description.

A female Micrathena duodecimspinosa (O. P. Cambridge, 1890) used the elasticity of her long dragline to repeatedly jerk her newly constructed egg sac up and down as she lowered it into the leaf litter below. Jerking may reduce the chances that the sac will be entangled in vegetation before it reaches the leaf litter or help insert it deeper into the litter, where it is visually camouflaged.

Sticky threads improve an orb web's ability to retain the insects that strike it, allowing a spider more time to subdue these insects before they can escape from the web. The adhesive capture threads found in most orb webs feature small droplets of aqueous material. Inside each droplet, glycoprotein granules coalesce to impart thread stickiness. An independent contrast analysis of threads produced by the adults of five species (Leucauge venusta, Argiope trifasciata, Micrathena gracilis, Cyclosa conica, Araneus marmoreus) and ontogenetic studies of the threads of two of these species show that the volume of material in a thread's droplets is directly related to its stickiness. Models based on these analyses predict thread stickiness to within an average of 11% of the mean measured values using measurements of droplet diameter and distribution that are easily made with a compound microscope. This approach will facilitate the inclusion of thread stickiness in studies that examine the properties and performance of spider orb-webs.

IntroductionBody temperature affects the physiological perfor-mance of ectothermic animals. Many studies havedemonstrated both behavioural thermoregulation andthe thermal consequences of habitat selection inectotherms (Henwood 1975; Bartlett & Gates 1967;Huey et al.1989). To understand the physiologicalconsequences of habitat selection for a given species,both natural temperature regimes and the effect oftemperature on important performance traits of theanimal must be determined (Huey 1991).Spiders are ectothermic organisms; both theirmetabolic rate and their activity levels vary with tem-perature. In web-building spiders, webs can be con-sidered records of the behaviour or activity of the ani-mal during the spinning process. The web providesthe spider with prey and transmits information aboutthe surrounding environment, such as the presence ofmates or predators. Thus, differences in web qualitydue to the ambient temperature could affect the forag-ing and reproductive success of a spider.Thermoregulation and the importance of favourablebody temperatures have been studied in spiders.Riechert & Tracy (1975) demonstrated the importanceof a favourable thermal environment to the reproduc-tive success of the desert spider Agelenopsis aperta(Gertsch). Biere & Uetz (1981) concluded that theorb-weavers, Micrathena gracilis(Walckenaer), ori-ent their webs to create exposures to the sun that resultin favourable body temperatures. Lubin et al.(Lubin,Kotzman & Ellner 1991; Lubin, Ellner & Kotzman1993) found evidence that web-site changes may berelated to thermal regime when they documented sea-sonal changes in webs and web sites of Latrodectusrevivensis(Shulov). The studies of Riechert & Tracy(1975), Biere & Uetz (1981), and Lubin et al.(1991,1993) suggest that favourable body temperatures areFunctionalEcology 199711,4–10

The phylogenetic relationships amongst the New World spiny orb-weaving spiders Micrathena and Chaetacis were assessed through parsimony and Bayesian analyses of morphological characters. A total of 146 characters was scored for ten outgroup taxa and 37 Micrathena and four Chaetacis species. The results indicate that Chaetacis nests within Micrathena and we propose Chaetacis as a junior synonym of Micrathena. Twelve subgeneric species groups of Micrathena are recognized and diagnosed. Species with extremely long spines evolved at least eight times in the genus and we suggest that this may be related to antipredator defences. Micrathena is primitively sexually monomorphic and extreme sexual size dimorphism has arisen at least six times in the genus. Most of these events are because of enlargement of the female in relation to the ancestral size, although in two cases sexual dimorphism was attained through male reduction, adding more data to the ‘giant females’ vs. ‘dwarf males’ controversy. The genus is probably of South American origin and has repeatedly invaded Central and North America. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166, 14–53.

Micrathena cyanospina (Lucas, 1835) Figs. 1���6 Epeira cyanospina Lucas, 1835: 70, pl. 140, fig. 3 (Female holotype from Island of Java, Indonesia, probably an error, never found in this place according Levi 1986: 566, certainly belongs to Neotropical region, lost, not examined). Plectana cyanospina: Walckenaer, 1842: 178. Meganopla cyanospina: Simon, 1864: 292. Acrosoma cyanospinum: Butler, 1873: 420. Micrathena cyanospina: Simon, 1895: 849, fig. 896; Chickering, 1960: 73, figs. 26���28; Levi, 1985: 566, figs. 620���624; Platnick, 2010. Diagnosis. Males of M. cyanospina can be distinguished from those of other species in the militaris group by the dark and uniform coloration (Figs. 1���3) and by the pilose posterior area of the abdomen (Figs. 1���3). The palp has a large and truncated embolus on the top of bulb and a triangular median apophysis (Fig. 4). Description. Female. Described by Levi, 1986: 566, figs. 620���624 and figure 6. Male (INPA-AR 6279). Specimen from the Pico da Neblina, municipality of S��o Gabriel da Cachoeira, state of Amazonas, Brazil. Carapace, sternum and abdomen black. Femur of legs I and II dark brown, third and fourth leg and remaining articles lighter brown. Carapace shiny brown with a round thoracic depression. Abdomen long, almost quadrangular in shape, with parallel sides. A light brown spot in the anterior third (Figs. 1���3) on the dorsum of abdomen. Total length, 5.5. Carapace, 1.9 long, 1.2 wide. First femur, 0.9; patella and tibia, 1.0; metatarsus, 0.6; tarsus, 0.5. Second patella and tibia, 0.9. Third patella and tibia, 0.6. Fourth femur, 1.2; patella and tibia, 0.9; metatarsus, 0.7; tarsus, 0.5. Paracymbium with enlarged base (Fig. 5), median apophysis triangular (Fig. 4). Variation. Total length of males ranges from 5.5 to 4.7. Distribution. Amazon region (Levi 1985). Natural history. Two males were captured at the Serra do Tapirapec�� Mountain at 800 m of elevation, one by nocturnal manual collection, and one with a beating tray, during the day. Another specimen was captured at the Pico da Neblina Mountain at 900 m., with a beating tray during the day. All specimens were collected in rain forest areas (Nogueira et al., 2011). Material examined. BRAZIL: Amazonas. Manaus, Reserva do km 41 (02�� 24 ���S 59 �� 44 ���W), 30.VIII��� 2.IX. 2008, C.M.P. Leite, 1 female (IBSP 160918); Presidente Figueiredo, Usina Hidrel��trica de Balbina, 1987 ��� 88, Equipe IBSP, 1 female (IBSP 10818); Barcelos, Serra do Tapirapec�� (1 �� 17 ���N 64 �� 19 ���W), X. 2006, A.A. Nogueira & R. Braga-Neto, 1 male 1 female (INPA AR 6284-6285), 1 male 1 female (IBSP 160916); S��o Gabriel da Cachoeira, Pico da Neblina (0�� 15 ���N 66 �� 10 ���W), IX. 2007, A.A. Nogueira, N.F. Lo-Man-Hung & D.F. Candiani, 1 male, 4 females (INPA AR 6279- 6283), 2 females (IBSP 160917); Par��. Bel��m, Mocambo, 24.I. 1967, M. Telles, 1 female (IBSP 42364); Paragominas, XII. 2005, M.G. Fonseca, 1 female (IBSP 71742)., Published as part of Nogueira, Andr�� A. & Brescovit, Antonio D., 2011, On the male of the orb weaving spider Micrathena cyanospina (Lucas, 1835) (Araneidae, Araneae), pp. 64-68 in Zootaxa 3096 on pages 65-67, DOI: 10.5281/zenodo.279112, {"references":["Lucas, H. (1835) Article: \" Epeira. \" Dictionnaire pittoresque d'Histoire naturelle et des phenomenes de la Nature, 3, 69 - 70.","Walckenaer, C. A. (1842) Histoire naturelle des Insects. Apteres. Paris, 2, 549 pp.","Simon, E. (1864) Histoire naturelle des araignees (araneides). Roret, Paris, 540 pp.","Butler, A. G. (1873) A list of the spiders of the genus Acrosoma. Proceedings of the Zoological Society of London, 1873, 420 - 429.","Simon, E. (1895) Histoire naturelle des araignees. Roret, Paris, 1, 761 - 1084.","Chickering, A. M. (1960) Six new species of Micrathena (Araneae, Argiopidae) from South America with notes on known species. Proceedings of the Zoological Society of London, 135, 65 - 89.","Levi, H. W. (1985) The spiny orb-weaver genera Micrathena and Chaetacis (Araneae: Araneidae). Bulletin of the Museum of Comparative Zoology at Harvard College, 150, 429 - 618.","Platnick, N. I. 2010. The world spider catalog, version 11.0. American Museum of Natural History, online at http: // research. amnh. org / entomology / spiders / catalog / index. html (acessed 24 February 2011)","Nogueira, A. A., J. P. P. Pena-Barbosa, E. M. Venticinque & A. D. Brescovit. (2011). The spider genus Chrysometa (Araneae, Tetragnathidae) from the Pico da Neblina and Serra do Tapirapeco mountains (Amazonas, Brazil): new species, new records, diversity and distribution along two altitudinal gradients. Zootaxa, 2772, 33 - 51."]}

Micrathena gaujoni Simon, 1897 Figures 14 ���16, 41 Micrathena gaujoni Simon, 1897: 466. Five female syntypes from Loja, Ecuador, deposited in MNHN 7832, not examined. Levi 1985: 478. Diagnosis. Males of M. gaujoni differ from all other Micrathena with a coxal hook by having an extremely long embolus projecting above the terminal apophysis and lying in a very large conductor, which occupies most of the tegulum in mesal view (Fig. 16). This species is most similar to M. pilaton Levi (Levi 1985: fig. 24), from which it differs by having a much larger terminal apophysis. For the female diagnosis see Levi (1985: 478). Description. Male from Estaci��n Biol��gica Yanayacu, Ecuador, (UFMG 3355). Carapace light brown, with a dark brown band on each side (Fig. 14). Chelicerae, endites, labium and sternum brown. Legs yellow proximally, brown distally. Dorsum of abdomen white with a median pattern of dark brown markings (Fig. 14); venter dark brown. Carapace with oval thoracic region, narrowest behind, a circular fovea and no dimples (Fig. 14). First coxa with hook and second femur with corresponding prolateral groove. Tibiae and femora I and II markedly ornamented with macrosetae on the dorsal surface; tibia II with two ventral rows of robust macrosetae, femur II with a single, median, ventral row of macrosetae (Fig. 15). Abdomen rectangular, elongated, with slightly convex sides and six tiny posterior lobes (Fig. 14). Total length, 5.07. Carapace 2.02 long, 1.37 wide at widest point. Abdomen 3.11 long. Length of first femur, 1.75; patella, 0.61; tibia, 1.29; metatarsus, 1.13; tarsus, 0.59. Second femur, 1.61; patella, 0.55; tibia, 1.09. Third femur, 1.02; patella, 0.35; tibia, 0.57. Fourth femur, 1.88; patella, 0.5; tibia, 1.11; metatarsus, 1.13; tarsus, 0.55. Palp with a large, undulated, twisted terminal apophysis, from which a drop-shaped membranous projection hangs. Embolus extremely long and filiform, projecting over the tegulum. Conductor very large, serving as a bed to the embolus, and attached to a pointed, sclerotized paramedian apophysis. Median apophysis comprised of three parts: a large, inverted U-shaped, basal projection, a lobe and a bended rim (Fig. 16). Paracymbium large and bilobed, otherwise unmodified. Female. Described by Levi (1985: 478). Notes. The described male has both palps with fully expanded basal hematodochae. The described male and three other sub-adult, apparently co-specific males were collected in the same expedition and in the same area as many adult and juvenile females of M. gaujoni were. No other Micrathena of the kirbyi or guerini groups were collected in the same expedition. This represents a new record for this species (Fig. 41). Natural history. The specimens were collected in an area of tropical rainforest, in the understory vegetation. Material examined. ECUADOR. Napo: Cosanga, Estaci��n Biol��gica Yanayacu (0�� 35 ��� 57 S 77 �� 53 ��� 26 ���W, 2128m ASL), A. J. Santos coll., 24���30 /XI/2009, 13, 8 ��, 5 juveniles (UFMG 3355)., Published as part of Magalh��es, Ivan L. F. & Santos, Adalberto J., 2011, Two new species and taxonomic notes on the Neotropical spiny orb-weaving spiders Micrathena and Chaetacis (Araneae: Araneidae), with remarks on the development of Micrathena excavata, pp. 39-56 in Zootaxa 2983 on pages 45-46, DOI: 10.5281/zenodo.205443, {"references":["Simon, E. (1897) Etudes arachnologiques. 27 e Memoire. XLII. Descriptions d'especes nouvelles de l'ordre des Araneae. Annales de la Societe Entomologique de France, 65, 465 - 510.","Levi, H. W. (1985) The spiny orb-weaver genera Micrathena and Chaetacis (Araneae: Araneidae). Bulletin of the Museum of Comparative Zoology, Harvard University 150, 429 - 618."]}

Micrathena ruschii (Mello-Leit��o, 1945), revalidated, new combination Figures 17 ���19, 41 Acrosoma ruschii Mello-Leit��o, 1945: 266, figs. 7���9. Female lectotype and three female paralectotypes, here designated, from Santa Tereza [19 �� 55 ���S 40 �� 35 ���W, 655 m], Esp��rito Santo, Brazil, deposited respectively in MNRJ 2566 and MNRJ 4255. First synonymized with Micrathena triangularis by Levi 1985: 512. Micrathena cicuta Gonzaga & Santos, 2004: 332 ���334, figs. 1���5. Female holotype from ��rea de Relevante Interesse Ecol��gico Floresta da Cicuta, Volta Redonda [22 �� 31 ���S 44 �� 7 ���W, 390 m], Rio de Janeiro, Brazil, deposited in IBSP 36322, not examined, nor found after the Butantan fire of May 2010. NEW SYNONYMY. Synonymy. As many of Mello-Leit��o���s type specimens, that of A. ruschii was not available to H.W. Levi at the time of his Micrathena revision. Based on the original description by Mello-Leit��o, Levi placed A. ruschii as a doubtful synonym of M. triangularis. Examination of the type specimens revealed that this species is, in fact, a senior synonym of the recently described M. cicuta. It comes from a locality which represents the northernmost record for the species, but is nonetheless not far away from the known range of M. cicuta. It is noteworthy, however, that Mello-Leit��o���s (1945) original illustrations and descriptions are not quite adequate for identifying the species, and that Gonzaga & Santos (2004) description should be used for this purpose. Diagnosis. The palp morphology is most similar to that of M. brevispina Keyserling (Levi 1985: fig. 393), with whom it shares a squared median apophysis. It differs by having the terminal apophysis with a distal, sclerotized tooth that points towards the apex of the embolus, by the conductor apex divided in two sclerotized parts, by the lightly sclerotized paramedian apophysis that points posteriorly and by the wider margin of the tegulum (Fig. 19). For the diagnosis of the female, see Gonzaga & Santos (2004: 332). Description. Male from Parque Nacional do Itatiaia, Itatiaia, Rio de Janeiro, Brazil (UFMG 4987). Carapace yellow, with two light brown bands on the sides (Fig. 18). Chelicerae, endites, labium and sternum yellow. Legs yellow proximally, brown distally. Abdomen dorsally white, bordered with black on the sides of the anterior half and in the posterior margin (Fig. 18); venter whitish gray, with a median black band extending from the posterior margin of the spinnerets to the end of the abdomen. Carapace with rounded thoracic region, a circular fovea and no dimples (Fig. 18), slightly dorsoventrally flattened in lateral view (Fig. 17). First coxa with hook and second femur with corresponding prolateral groove. Tibiae and femora I and II and tibia IV ornamented with macrosetae on the dorsal surface, strongest in femur I (Fig. 18). Abdomen rectangular, elongated, narrowest behind and with slightly undulated sides (Fig. 18). Total length, 4.95. Carapace 2.17 long, 1.81 wide at widest point. Abdomen 3.19 long. Length of first femur, 1.91; patella, 0.65; tibia, 1.35; metatarsus, 1.13; tarsus, 0.48. Second femur, 1.64; patella, 0.54; tibia, 1.07. Third femur, 0.99; patella, 0.41; tibia, 0.61. Fourth femur, 1.83; patella, 0.46; tibia, 1.03; metatarsus, 1.14; tarsus, 0.50. Palp with a large, membranous, flattened terminal apophysis with a distal sclerotized tooth, covering the embolus. Embolus thick, curved and with a truncate, almost bifid, apex. Conductor composed of two sclerotized parts, the larger posteriorly directed, and a membranous digitiform lobe. Paramedian apophysis lightly sclerotized, not attached to the conductor, posteriorly directed. Median apophysis comprised of three parts: a small basal projection located between the paramedian apophysis and the radix, a lobe and a bended rim (Fig. 19). Paracymbium large and bilobed, otherwise unmodified. Female. Described by Gonzaga & Santos (2004: 333). Notes. The male was collected at the periphery of a female���s orb-web, in one of the supporting threads, in an area where two other females had been collected. The collecting site is 50 km away from Floresta da Cicuta, Volta Redonda, the type locality of M. cicuta. The specimen was collected with the left palp missing and the right one slightly expanded. To facilitate comparisons with other species, we illustrate the mirror image of this palp, as it was the right one (Fig. 19). The species is recorded for the first time for Parque Nacional do Itatiaia, Itatiaia, Rio de Janeiro; and Juiz de Fora, Minas Gerais (both localities in Brazil; Fig. 41). Natural history. Specimens were collected by visual searching in the understory vegetation of montane Atlantic rainforest. Material examined. BRAZIL. Minas Gerais: Juiz de Fora, Reserva Biol��gica Municipal Po��o D���Anta (21 �� 45 ��� 37.84 ������S 43 �� 19 ��� 10.24 ������W, 810 m), G.H.F. Azevedo & A.J. Santos coll., 02/IV/2011, 1�� (UFMG 5224). Rio de Janeiro: Itatiaia, Parque Nacional do Itatiaia (12 �� 27 ��� 17 ������S 44 �� 36 ��� 29.8 ������W, 720 m), G.H.F. Azevedo et al. coll., 15���22 /II/2011, 13, 3 �� (UFMG 4987)., Published as part of Magalh��es, Ivan L. F. & Santos, Adalberto J., 2011, Two new species and taxonomic notes on the Neotropical spiny orb-weaving spiders Micrathena and Chaetacis (Araneae: Araneidae), with remarks on the development of Micrathena excavata, pp. 39-56 in Zootaxa 2983 on pages 46-48, DOI: 10.5281/zenodo.205443, {"references":["Mello-Leitao, C. F. (1945) Tres novas especies de Gasteracanthinae e notas sobre a subfamilia. Anais da Academia Brasileira de Ciencias, 17, 261 - 267.","Levi, H. W. (1985) The spiny orb-weaver genera Micrathena and Chaetacis (Araneae: Araneidae). Bulletin of the Museum of Comparative Zoology, Harvard University 150, 429 - 618.","Gonzaga, M. O. & Santos, A. J. (2004) A new species and a new synonymy in the spiny orb-weaver spider genus Micrathena (Araneae, Araneidae). Journal of Arachnology, 32, 332 - 335."]}

Micrathena yanomami new species Figures 9 ���13, 41 Type material. Holotype female and paratype female, both from Bebedouro Novo, Parque Nacional do Pico da Neblina, S��o Gabriel da Cachoeira, Amazonas, Brazil (00�� 44 ��� 53.88 ���N, 65 �� 58 ��� 31.80 ���W, 860 m), A.A. Nogueira coll., deposited in INPA 6286 and INPA 6287, respectively. Etymology. The specific name honors the Yanomami, a group of native American people whose territory includes the Pico da Neblina, the type locality. Diagnosis. Micrathena yanomami females differ from the other species of the triangularispinosa group by the coloration pattern of the carapace, with a black band along its entire edge, by the granulation in the carapace edges and by the setal bases of the femora, which are more projected and domed (Figs. 9, 10). The epigynum is similar to that of M. triangularispinosa (De Geer) (Levi 1985: figs. 474���476) but differs by the more robust lobe, which is also more detached from the bulge (Fig. 11, 12), and by the median plate of the epigynum in posterior view, which is wider than long and has a mushroom-shaped clear area embracing two dark spots (Fig. 13). Description. Female (holotype). Carapace orange brown, with a black band along its entire edge and around the eyes (Fig. 9). Chelicerae dark brown. Endites and labium orange brown. Sternum yellowish white. Coxae orange brown, legs dark brown, darkest in the femora. Dorsum of abdomen yellow, sides dark brown, venter pale yellow; spines red, with a black band extending from one posterior spine to the other; sclerotized ring around spinnerets black. Carapace dome-shaped, almost glabrous, with fine granulation on the edges of the thoracic area, and without dimples; thoracic fovea an indistinct circular marking; median ocular area slightly projected. Abdomen trapezoidal, widest posteriorly. Four pairs of spines on the abdomen, the first and the third the longest; the fourth only an indistinct and sclerotized nipple below the large posterior spines (Figs. 9, 10). Total length, 5.13. Carapace 2.02 long, 1.62 wide at its widest point. Abdomen 3.19 long. Length of first femur, 1.66; patella, 0.63; tibia, 1.18; metatarsus, 0.92; tarsus, 0.59. Second femur, 1.5; patella, 0.57; tibia, 1.05. Third femur, 1.13; patella, 0.41; tibia, 0.72. Fourth femur, 2.09; patella, 0.57; tibia, 1.14; metatarsus, 1.13; tarsus, 0.65. Epigynum with a domed bulge, from which a lobe projects posteriorly (Figs. 11, 12). Posterior median plate wider than long, mushroom-shaped and embracing two dark spots that correspond to the region where the copulatory openings lie (Fig. 13). Male. Unknown. Relationships. Micrathena yanomami belongs to the triangularispinosa group sensu Levi (1985), based on the domed carapace, projected median eyes and similar morphology of the abdomen and genitalia. Variation. The holotype has one of the anterior spines shorter than the other; the paratype has both of them long, but they are twisted like a goat's horn (in the first case, probably an abnormality; in the second case, probably an artifact of the process of preservation). Females (N= 2) vary in total length from 5.13 to 5.26; carapace length varies from 2.02 to 2.04. Distribution. Examined specimens come only from the type locality (Fig. 41). According to the collector of the type specimens, the species occurs at two other localities in Pico da Neblina: Cachoeira do Tucano (00�� 39 ���54.00���N, 65 �� 56 ���09.60���W, 100 m) and Bebedouro Velho (00�� 41 ��� 54.96 ���N, 65 �� 55 ��� 40.44 ������W, 400 m) (A.A. Nogueira, pers comm.). I. Cizaukas (pers. comm.) reports examining material of this species from the following locality: BRAZIL. Amazonas: Manaus [Projeto Din��mica Biol��gica de Fragmentos Florestais, Reserva do Km 41, 2�� 24 ��� 26 ���S, 59 �� 43 ��� 40 ������W]. However, these specimens have been lost in the fire that affected the arachnological collection of Instituto Butantan in May, 2010 before they could be examined by the authors of the present study. Material examined. Only the types., Published as part of Magalh��es, Ivan L. F. & Santos, Adalberto J., 2011, Two new species and taxonomic notes on the Neotropical spiny orb-weaving spiders Micrathena and Chaetacis (Araneae: Araneidae), with remarks on the development of Micrathena excavata, pp. 39-56 in Zootaxa 2983 on pages 43-45, DOI: 10.5281/zenodo.205443, {"references":["Levi, H. W. (1985) The spiny orb-weaver genera Micrathena and Chaetacis (Araneae: Araneidae). Bulletin of the Museum of Comparative Zoology, Harvard University 150, 429 - 618."]}

Micrathena yanomami new species Figures 9 –13, 41 Type material. Holotype female and paratype female, both from Bebedouro Novo, Parque Nacional do Pico da Neblina, São Gabriel da Cachoeira, Amazonas, Brazil (00º 44 ’ 53.88 ”N, 65 º 58 ’ 31.80 ”W, 860 m), A.A. Nogueira coll., deposited in INPA 6286 and INPA 6287, respectively. Etymology. The specific name honors the Yanomami, a group of native American people whose territory includes the Pico da Neblina, the type locality. Diagnosis. Micrathena yanomami females differ from the other species of the triangularispinosa group by the coloration pattern of the carapace, with a black band along its entire edge, by the granulation in the carapace edges and by the setal bases of the femora, which are more projected and domed (Figs. 9, 10). The epigynum is similar to that of M. triangularispinosa (De Geer) (Levi 1985: figs. 474–476) but differs by the more robust lobe, which is also more detached from the bulge (Fig. 11, 12), and by the median plate of the epigynum in posterior view, which is wider than long and has a mushroom-shaped clear area embracing two dark spots (Fig. 13). Description. Female (holotype). Carapace orange brown, with a black band along its entire edge and around the eyes (Fig. 9). Chelicerae dark brown. Endites and labium orange brown. Sternum yellowish white. Coxae orange brown, legs dark brown, darkest in the femora. Dorsum of abdomen yellow, sides dark brown, venter pale yellow; spines red, with a black band extending from one posterior spine to the other; sclerotized ring around spinnerets black. Carapace dome-shaped, almost glabrous, with fine granulation on the edges of the thoracic area, and without dimples; thoracic fovea an indistinct circular marking; median ocular area slightly projected. Abdomen trapezoidal, widest posteriorly. Four pairs of spines on the abdomen, the first and the third the longest; the fourth only an indistinct and sclerotized nipple below the large posterior spines (Figs. 9, 10). Total length, 5.13. Carapace 2.02 long, 1.62 wide at its widest point. Abdomen 3.19 long. Length of first femur, 1.66; patella, 0.63; tibia, 1.18; metatarsus, 0.92; tarsus, 0.59. Second femur, 1.5; patella, 0.57; tibia, 1.05. Third femur, 1.13; patella, 0.41; tibia, 0.72. Fourth femur, 2.09; patella, 0.57; tibia, 1.14; metatarsus, 1.13; tarsus, 0.65. Epigynum with a domed bulge, from which a lobe projects posteriorly (Figs. 11, 12). Posterior median plate wider than long, mushroom-shaped and embracing two dark spots that correspond to the region where the copulatory openings lie (Fig. 13). Male. Unknown. Relationships. Micrathena yanomami belongs to the triangularispinosa group sensu Levi (1985), based on the domed carapace, projected median eyes and similar morphology of the abdomen and genitalia. Variation. The holotype has one of the anterior spines shorter than the other; the paratype has both of them long, but they are twisted like a goat's horn (in the first case, probably an abnormality; in the second case, probably an artifact of the process of preservation). Females (N= 2) vary in total length from 5.13 to 5.26; carapace length varies from 2.02 to 2.04. Distribution. Examined specimens come only from the type locality (Fig. 41). According to the collector of the type specimens, the species occurs at two other localities in Pico da Neblina: Cachoeira do Tucano (00º 39 ’54.00”N, 65 º 56 ’09.60”W, 100 m) and Bebedouro Velho (00º 41 ’ 54.96 ”N, 65 º 55 ’ 40.44 ’’W, 400 m) (A.A. Nogueira, pers comm.). I. Cizaukas (pers. comm.) reports examining material of this species from the following locality: BRAZIL. Amazonas: Manaus [Projeto Dinâmica Biológica de Fragmentos Florestais, Reserva do Km 41, 2º 24 ’ 26 ”S, 59 º 43 ’ 40 ’’W]. However, these specimens have been lost in the fire that affected the arachnological collection of Instituto Butantan in May, 2010 before they could be examined by the authors of the present study. Material examined. Only the types.

Micrathena plana (C. L. Koch, 1836) Acrosoma planum C.L. Koch, 1836: 81, fig. 228. Female holotype from Brazil, deposited in Zoologische Staatssammlung, Munich, destroyed. Micrathena plana, Levi 1985: 509, figs. 311���325; Platnick 2011 (complete synonymic list). Micrathena ornata Mello-Leit��o, 1932: 86, fig. 4. Female holotype from Niter��i, Rio de Janeiro, Brazil [22 �� 53 ���S 43 �� 5 ���W, 5m ASL], deposited in MNRJ 18276, examined. Levi 1985: 546, figs. 521���524. NEW SYNONYMY. Synonymy. The type of M. ornata was examined by H.W. Levi some time before he started his revision of the genus (Levi 1985). He did not illustrate the carapace of the specimen in lateral view and thought it to be dome-shaped, when it is actually sculptured, with a high thorax. Thus it was inadequately placed in the triangularispinosa group. When Levi redescribed M. plana, he did not realize it was the same species as M. ornata, which is known only from the holotype, and did not account for the synonymy. It can be clearly seen, both from the specimen and from Levi���s illustrations, that M. ornata possess the convex transverse bar, small epigynal lobe and abdominal spine pattern that diagnose M. plana., Published as part of Magalh��es, Ivan L. F. & Santos, Adalberto J., 2011, Two new species and taxonomic notes on the Neotropical spiny orb-weaving spiders Micrathena and Chaetacis (Araneae: Araneidae), with remarks on the development of Micrathena excavata, pp. 39-56 in Zootaxa 2983 on page 48, DOI: 10.5281/zenodo.205443, {"references":["Koch, C. L. (1836). Die Arachniden. Nurnberg, Dritter Band, 104 pp.","Levi, H. W. (1985) The spiny orb-weaver genera Micrathena and Chaetacis (Araneae: Araneidae). Bulletin of the Museum of Comparative Zoology, Harvard University 150, 429 - 618.","Platnick, N. I. (2011) The World Spider Catalog, version 11.5. The American Museum of Natural History, New York. Available from http: // research. amnh. org / iz / spiders / catalog / INTRO 1. html. DOI: 10.5531 / db. iz. 0001 (accessed 22 January 2011).","Mello-Leitao, C. F. (1932) Notas sobre as Micratheneas do Brasil. Annaes da Academia Brasileira de Sciencias, 4, 73 - 97."]}

Micrathena shealsi Chickering, 1960 (Figs. 1���18; Map 19) Micrathena shealsi Chickering, 1960 a: 8, figs. 13���17 (Holotype female from Sunchal, Argentina, deposited in Invertebrate Zoology Collection of Museum Comparative Zoology���MCZ 23053, not examined). Micrathena shealsi: Levi, 1985: 458, figs. 74���78; Platnick, 2011. New records. ARGENTINA: Jujuy: Yala (24 ��07' 13 ''S, 65 �� 27 ' 24 ''W, 1888m.a.s.l.), 20 May 1983 (P. Goloboff), 1 female (MACN-Ar 25178); Calilegua, Parque Nacional Calilegua, Seccional Aguas Negras (23 �� 45 ' 43.3 ''S, 64 �� 51 '04.7''W, 605m. a.s.l.), 27���31 January 2009 (M. Izquierdo, L. Zapata & M. Akmentis), 1 male (MACN-Ar 27850); same loc., near Monolito (23 �� 40 ' 27 ''S, 64 �� 54 '01''W, 1714m.a.s.l.), 19 October 2009 (G. Rubio & M. Pocco), 1 female (MACN-Ar 27851). Salta: Quebrada de San Lorenzo, site 1 (24 �� 42 ' 51.84 "S, 65 �� 31 ' 6.96 "W, 1833m.a.s.l.), 26���28 April 2006 (G. Rubio, J. Corronca, B. Cava, V. Olivo & A. Gonz��lez-Reyes), 2 females (MACN-Ar 27852); same loc., site 2 (24 �� 43 ' 9.60 "S, 65 �� 30 ' 56.40 "W, 1691m.a.s.l.), same date (same leg.), 6 specimens (IEBI); same loc., site 3 (24 �� 43 ' 16.80 "S, 65 �� 30 '39.00"W, 1587m.a.s.l.), same date (same leg.), 1 specimen (IEBI); same loc., site 4 (24 �� 43 ' 17.04 "S, 65 �� 30 ' 25.80 "W, 1575m.a.s.l.), same date (same leg.), 2 specimens (IEBI); same loc., site 5 (24 �� 43 ' 16.32 "S, 65 �� 30 ' 7.92 "W, 1560m.a.s.l.), same date (same leg.), 7 specimens (IEBI); road to El Carmen, site 1 (24 �� 31 ' 13.36 "S, 65 �� 21 ' 4.02 "W, 1547m.a.s.l.), same date (same leg.), 2 specimens (IEBI); same loc., site 2 (24 �� 30 ' 33.30 "S, 65 �� 20 ' 27.13 "W, 1587m.a.s.l.), same date (same leg.), 1 specimen (IEBI); same loc., site 3 (24 �� 30 ' 15.84 "S, 65 �� 20 ' 11.40 "W, 1516m.a.s.l.), same date (same leg.), 2 specimens (IEBI). Tucum��n: Cochuna (27 �� 19 ' 19.97 "S, 65 �� 55 ' 38.01 "W, 1162m.a.s.l.), 25 March 2011 (C. Arga��araz), 1 male (MACN-Ar 27853); same loc., 0 9 April 2011 (C. Arga��araz & G. Rubio), 4 males, 6 females (MACN-Ar 27854), and 1 male (MACN-Ar 27856); monument to El Indio (27 �� 2 ' 54.24 "S, 65 �� 40 ' 8.76 "W, 1065m.a.s.l.), 21 February 2011 (G. Rubio & L. Acosta), 1 sub-adult male (MACN-Ar 27855). Diagnosis. Males of M. shealsi (Figs. 1 ���7, 9��� 15) resembles M. bifida (Taczanowski) from Peru by general habitus, and by the palp bearing a tegulum lobe in ectal view (Levi 1985: figs. 45, 47) but it can be distinguished from it by the palpal morphology (Figs. 5 ���7, 9��� 13) (M. shealsi has a distinctive shape of the median and terminal apophyses, Fig. 6, 10). Females of M. shealsi differ from congeners by the absence of a scape on the epigynum (Fig. 16) and by the ventral coloration (light sternum, and depigmented median area of the abdomen venter: Levi 1985). Micrathena shealsi was erroneously taken as ��� M. nigrichelis with scape of epigynum torn off��� (Levi 1985). However, these species can be easily separated by the above-mentioned chromatic pattern (Levi 1985), and by the dimensions of the cephalic region (smaller in M. shealsi); the latter feature is also present in males. Description. Male from Cochuna, Tucum��n (MACN-Ar 27856): Carapace orange (in nature���Fig. 18) or yellowish (in alcohol), black on sides and with a blackish longitudinal strip starting near the posterior eyes towards thoracic groove (Figs. 1, 18). Very shallow dimples on each side of thoracic groove. Chelicerae pale yellow. Sternum and coxae light yellow, with dark pigment near the articulation. Legs orange-brown, first pair darker. Coxa I with hook, femur II with groove (Figs. 14���15). Tibia I-II with macrosetae; ventral side of femur II with row of 8���9 spines. Abdomen longer than wide, rectangle-shaped, without humps; yellowish-white dorsally (slightly orange in nature) with three black marks on each side, one dark median longitudinal strip on posterior two thirds; end of abdomen black; venter between epigastric furrow and spinnerets pale yellow, spinnerets and the rest of venter black-grayish (Fig. 3). Palp with reddish-brown general color (Figs. 17���18). Body total length from AME to tip of abdomen 5.51; carapace length 2.10, width 1.47; sternum length 0.91, width 0.52; abdomen length 3.57, width 0.98. Leg formula I/IV/II/III. Leg lengths (I/II/III/IV): femur 2.03 / 1.78 / 1.12 / 2.17; patella 0.64 / 0.58 / 0.38 / 0.49; tibia 1.54 / 1.22 / 0.63 / 1.20; metatarsus 1.15 / 1.12 / 0.56 / 1.33; tarsus 0.63 / 0.63 / 0.35 / 0.66; total leg 5.99 / 5.33 / 3.04 / 5.85. Female (Holotype, MCZ 23053): See Chickering (1960 a: 8, figs. 13���17). Internal genitalia as in figure 8. Variation. Males (n= 6): Body total length 4.83���5.51; carapace length 2.03���2.17, width 1.4���1.5; sternum width 0.50���0.56; abdomen length 3.01���3.57, width 0.87���1.05. Total leg (I/II/III/IV) 5.98���6.12 / 5.28���5.37 / 3.01���3.11 / 5.85���6.04. Natural history (Figs. 17���18). Males of M. shealsi were found in most cases on the upper periphery of the female webs, hanging from a silk line. In only one case, a male was found in a small orb-web located under the female site. Females of M. shealsi sometimes build their web near other female webs, forming groups (of 2 to 5 individuals) in the lower stratum of vegetation, no higher than 60 cm. In such cases males were not observed. Ongoing ecological research (G. D. Rubio, unpublished) suggests that this species is strongly associated with the Yungas rainforest habitat. Geographic distribution (Fig. 19). Micrathena shealsi was only known from the type locality ���Sunchal, Argentina ��� (Chickering 1960 a). Although Levi (1985) assigned this locality to Salta Province, ���Sunchal��� in the latter does not fall within the rainforests region (Fig. 19); in contrast, ���Sunchal��� or ���El Sunchal��� in Tucum��n Province, seems more likely for a rainforest-dwelling spider. New records here provided reveal that M. shealsi has an extensive distribution in the Yungas, corresponding to the higher altitudinal belt (~ 1700 m.) of the mountain forests and rainforests from Tucum��n, Salta and Jujuy Provinces (Fig. 19)., Published as part of Arga��araz, Carina I. & Rubio, Gonzalo D., 2011, The spider Micrathena shealsi Chickering, 1960 (Araneae, Araneidae): description of the male, with new data on its geographic distribution, pp. 52-58 in Zootaxa 3104 on pages 53-54, DOI: 10.5281/zenodo.207326, {"references":["Chickering, A. M. (1960 a) Three new species of Micrathena (Araneae: Argiopidae) from South America. Breviora, 121, 1 - 11.","Levi, H. W. (1985) The Spiny Orb-Weaver Genera Micrathena and Chaetacis (Araneae: Araneidae). Bulletin of the Museum of Comparative Zoology, 150, 429 - 618.","Platnick, N. I. (2011) The world spider catalog, version 12. American Museum of Natural History. Available from: http: // research. amnh. org / entomology / spiders / catalog / index. html (26 September 2011)."]}

Micrathena horrida (Taczanowski, 1873) Acrosoma horridum Taczanowski, 1873: 281, fig. 31. Female holotype from Cayenne, French Guiana [4 �� 55 ���N 52 �� 19 ���W, 8m ASL], deposited in Polska Akademia Nauk, Warszawa, not examined. Micrathena horrida, Levi 1985: 596, figs. 774���783; Platnick 2011 (complete synonymic list). Micrathena mastonota Mello-Leit��o 1940: 209. Female holotype from Colatina, Esp��rito Santo, Brazil [19 �� 31 ���S 40 �� 37 ���W, 38m ASL], Mario Rosa coll., deposited in MNRJ 58345, examined. Levi 1985: 446 (nomen dubium). NEW SYNONYMY. Synonymy. The holotype of M. mastonota was not available to Levi (1985) at the time of his revision and he regarded it as being lost. He could not identify the species from the original description and considered it as a nomen dubium, suggesting the possibility that it could be a synonym of M. triangularis. The type was located at MNRJ and is an adult female of M. horrida, with all the diagnostic characters of the species reported by Levi (1985: 598, figs. 774���780). This represents the first record of this species for the state of Esp��rito Santo, Brazil., Published as part of Magalh��es, Ivan L. F. & Santos, Adalberto J., 2011, Two new species and taxonomic notes on the Neotropical spiny orb-weaving spiders Micrathena and Chaetacis (Araneae: Araneidae), with remarks on the development of Micrathena excavata, pp. 39-56 in Zootaxa 2983 on page 48, DOI: 10.5281/zenodo.205443, {"references":["Taczanowski, L. (1873) Les araneides de la Guyane francaise. Horae Societatis Entomologicae Rossicae, 9, 113 - 150, 261 - 286.","Levi, H. W. (1985) The spiny orb-weaver genera Micrathena and Chaetacis (Araneae: Araneidae). Bulletin of the Museum of Comparative Zoology, Harvard University 150, 429 - 618.","Platnick, N. I. (2011) The World Spider Catalog, version 11.5. The American Museum of Natural History, New York. Available from http: // research. amnh. org / iz / spiders / catalog / INTRO 1. html. DOI: 10.5531 / db. iz. 0001 (accessed 22 January 2011).","Mello-Leitao, C. F. (1940) Aranhas do Espirito Santo coligidas por Mario Rosa, em 1936 e 1937. Archivos de Zoologia do Estado de Sao Paulo, 2, 199 - 214."]}

Published descriptions of egg sac construction behavior in araneids are scarce. We describe egg sac construction and oviposition in one individual of the poorly known araneid Pozonia nigroventris (Bryant 1936) and two individuals of Micrathena sp. These spiders folded dead leaves to protect their eggs. All individuals pulled up and hung a dead leaf above the forest floor, oviposited on the leaf, and then folded the leaf around the egg sac. They then deposited the enclosed egg sac in the leaf litter below. The use of dead leaves in this way probably evolved convergently, since these genera are only distantly related. Smithsonian Tropical Research Institute, Panama, USA UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biología

Foi realizado um levantamento da fauna de aranhas orbitelas da Reserva Florestal do Morro Grande e região (Cotia e Ibiúna-SP). Foram amostradas 16 áreas, oito na reserva e oito em fragmentos florestais. Quatro das áreas da reserva possuíam uma vegetação madura, enquanto as outras apresentavam vegetação secundária, assim como os fragmentos. As amostragens foram realizadas em dezembro de 2002 e março de 2003, e o método empregado foi a coleta manual noturna. Obteve-se um total de 384 amostras, correspondendo a 24 por área. Foram obtidas 12.683 aranhas orbitelas, 3.148 das quais adultas (24,8%) e 9.535 jovens (75,2%). As adultas foram distribuídas em 121 espécies, pertencentes a sete famílias. Trata-se da maior riqueza já observada para a guilda em áreas de Mata Atlântica. Cada período de coleta apresentou 27 espécies exclusivas, e 67 estiveram presentes em ambos. A família mais rica foi Araneidae (76 spp), seguida por Tetragnathidae (26 spp), Theridiosomatidae (nove spp), Uloboridae (seis spp), Anapidae (duas spp), Mysmenidae (uma sp) e Symphytognathidae (uma sp). A distribuição das espécies pelas famílias parece refletir a riqueza desses grupos no Brasil e no mundo, com exceção de Theridiosomatidae, que teve um número de espécies maior do que o esperado. A abundância relativa dessas famílias apresentou padrão semelhante ao da riqueza. A espécie dominante foi Micrathena nigrichelis, com 320 indivíduos, seguida por Micrathena guanabara (306 indivíduos), Mangora sp.2 (258 indivíduos) e Wagneriana janeiro (171 indivíduos). A comunidade apresentou uma baixa dominância (H'=3,11) e alta equitabilidade (E=0,835), estando de acordo com o esperado para ambientes tropicais. Foram empregados sete estimadores de riqueza não paramétricos, e as estimativas variaram entre 130,9 (Bootstrap) e 155,9 (Jackknife 2) espécies. No entanto, apesar do grande esforço amostral (intensidade de coleta de 26:1), nenhum dos estimadores atingiu a asíntota, uma vez que o número de espécies raras (singletons, doubletons, uniques e duplicates) permaneceu estável. A distribuição das espécies entre as oito áreas da Reserva do Morro Grande foi verificada através de uma (DCA), e os resultados mostraram que houve uma separação entre as áreas de vegetação madura e as de vegetação secundária. A análise também apontou espécies associadas a cada um desses ambientes, e os resultados foram comparados aos encontrados em outros inventários. O grande número de espécies e indivíduos de aranhas orbitelas encontrados neste trabalho ressalta a importância das florestas da área de estudo e principalmente da Reserva do Morro Grande como unidade de conservação.

Web orientation (direction that spiders faced) in a forest-dwelling orb web-building spider, Micrathena gracilis (Araneidae), was related to the microhabitat where webs are constructed. Individuals in shaded (closed) microhabitats faced predominantly north/south, while those in well- lighted microhabitats (open and patchy) faced east/west. Several variables were examined in an effort to explain the patterns that emerged. Wind speeds were found to be so low within the interior of the forest that available instrumentation could not measure them. Nevertheless, webs were not aligned with prevailing winds. There were no significant differences in web site parameters (height, bridge thread distance) between microhabitats. Artificial web studies indicate that prey abundance is greater in open microhabitats and at lower heights, though prey movement through all microhabitats is nondirectional. Spider body temperature, however, was positively correlated with the amount of solar radiation striking the animal, which varied with both microhabitat and direction of orientation. The compass orientation of a spider's web influenced the amount of radiation to which the spider was exposed, and thus affected its body temperature. A model is proposed that relates the time an individual spider can spend on its web to the amount of heat accrued by the spider. Both too little or excessive body heat might affect activity. Since time on the web is positively correlated with total prey captured, more time spent on the web effectively increases the availability of prey. Web orientation is suggested as a behavioral thermoregulatory mechanism which allows Micrathena gracilis enough flexibility to exploit a variety of microhabitats and to maximize its time on the web, thus optimizing its prey take in each habitat.