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Many species described in the past have lacked a complete description a thing that led to misidentification and to describe the already described species as new species. A detailed analysis of the Indian spider species Uloborus danolius resulted in the synonymization with Zosis geniculata because of its misidentification. [ABSTRACT FROM AUTHOR]

Behavior is often phylogenetically informative and detailed descriptions of behavior have been used to support taxonomic relationships in several groups, such as birds, lizards, and arthropods. Web building behavior has provided informative traits to several spider families, but observations are lacking for other families, such as wall spiders Oecobiidae. Recent phylogenetic hypotheses based on molecular traits placed oecobiids either close to cribellate orb weavers (Uloboridae) or to long-spinneret spiders (Hersiliidae). Here, we describe for first time the web construction behavior and details of the web design in the oecobiid Oecobius concinnus Simon 1893 (Oecobiidae). We compare them with uloborid and araneoid orb weavers. If Oecobiidae and Uloboridae are closely related, we expect that O. concinnus share some web construction behaviors with these orb weavers. Video recordings and analyses of web structures suggest the sequence of web construction (radii, then sticky spiral construction) and the arrangement of cribellate threads are possible homologies between Oecobiidae and orb weavers, supporting a close relationship of Oecobiidae with Uloboridae. [ABSTRACT FROM AUTHOR]

Group-living spiders are rare, and can be divided into multiple subcategories based on their tolerance of group mates. While social spiders are cooperative, colonial spiders are often antagonistic towards conspecifics. We examined colony dynamics in a colonial species, Philoponella republicana (Simon, 1891), focusing on aggressive behaviors to further understand this understudied species. We studied whether web region, sex ratio, web size, or spider size affected aggression. We also tested whether colony members discriminate against conspecific intruders, since this behavior, known as group closure, is prevalent in many other group-living animals but had not yet been tested in colonial spiders. Colony mates were often aggressive due to competition for limited resources, such as mates and orb webs, yet several characteristics of this species may reduce these competitive forces. First, female-biased secondary sex ratios appear to reduce male-male and female-male competition. Moreover, although some individuals defended orb webs, other areas in the communal web were not defended. Philoponella republicana also did not exhibit group closure. Our results further confirm that aggression between males decreases in colonies with more female-biased secondary sex ratios, and larger individuals correlate with a higher frequency of aggressive interactions. Moreover, we raise new questions concerning the evolutionary pressures that shape coloniality in spiders. [ABSTRACT FROM AUTHOR]

This first-ever extensive review of the construction behaviour of orb webs, of webs secondarily derived from orbs, and of non-orbs shows that the evidence favouring monophyly over convergent evolution of orbs is stronger than previously appreciated. The two major orb-weaving groups, Uloboridae and Araneoidea, share 31 construction behaviour traits, 20 of which are likely to be both derived and to have feasible alternatives, making convergence an unlikely explanation. Convergence in two lineages seems unlikely, and convergence in five different lineages, as proposed in some recent molecular studies of phylogeny, is even less credible. A further set of seven shared responses in orb design to experimentally constrained spaces also supports orb monophyly. Finally, a 'control' case of confirmed convergence on similar 'pseudo-orbs' in a taxonomically distant group also supports this argument, as it shows a low frequency of behavioural similarities. I argue that the omission of behavioural data from recent molecular studies of orb web evolution represents a failure of the analytic techniques, not the data, and increases the risk of making mistakes. In general, phylogenetic studies that aim to understand the evolution of particular phenotypes can benefit from including careful study of the phenotypes themselves. [ABSTRACT FROM AUTHOR]

A new species from the spider genus Philoponella Mello-Leitão 1917 - Philoponella rostralis n. sp. (♂♀) is diagnosed and described from the Kottapara Hills, Western Ghats, Kerala, India. A detailed description of its morphology, diagnostic features, photographs and the depictions of the copulatory organs of both sexes are given. [ABSTRACT FROM AUTHOR]

Indian sandalwood Santalum album L. plantations in Karnataka were surveyed to study the diversity and abundance of spider fauna. A total of 1,244 individuals belonging to 56 spider species in 40 genera under 14 families were recorded in the sandalwood plantations. Among the spider families recorded, Araneidae was the most dominant with 15 species in nine genera followed by Salticidae with 13 species in 10 genera, Thomisidae with seven species in four genera, Oxyopidae with four species in three genera, Uloboridae with four species in a genus, and Theridiidae by three species each under three genera. Lycosidae and Sparassidae are represented by two species under two genera each. The families Cheiracanthiidae, Clubionidae, Hersiliidae, Philodromidae, and Pholcidae are represented by a species each. The pruning of sandalwood revealed a significant negative effect on the occurrence and distribution of spiders. [ABSTRACT FROM AUTHOR]

The present article deals with the faunal diversity of five families of araeneomorph spiders, viz. Titanoecidae, Trachelidae, Trochanteriidae, Uloboridae, and Zodariidae (Arachnida: Araneae) in different Indian states and union territories. None of the spider species of these families is recorded from Bihar, Daman & Diu and Dadar & Nagar Haveli, Delhi, Jharkhand, Manipur, Nagaland, Punjab, and Telangana. Among these, the largest family is Zodariidae which is represented by 32 species belonging to 12 genera out of which majority (29 species) are endemic followed by Uloboridae which comprises 30 species placed in 5 genera. Other families are very poorly represented in India. Only 5 species of a single genus, Plator Simon, 1880 are recorded in Trochanteriidae; 8 species in 3 genera in Trachelidae and 10 species in 3 genera in Titanoecidae are recorded. Only two species, Uloborus danolius Tikader, 1969 and Zosis geniculata (Olivier, 1789) are distributed in 15 and 14 states and union territories of India, respectively. Maximum number of spider species of these families were recorded in Maharashtra (28 species) followed by Kerala (23 species), Tamil Nadu (19), Gujarat (16 species), West Bengal (12 species), Karnataka (11 species), Uttarakhand (9 species) and lesser number in other states and union territories. Out of 84 species recorded of these 5 families, 67 species are endemic and 3 species seem to be erroneous records. [ABSTRACT FROM AUTHOR]

The genus Uloborus Latreille, 1806 includes 80 species and subspecies worldwide, out of these, nine species were reported from India. The male of Uloborus jabalpurensis Bhandari & Gajbe, 2001, among these nine species, is described and illustrated in detail with its distribution map. [ABSTRACT FROM AUTHOR]

The use of different sampling protocols has been found to give a more reliable detail of the faunal composition of spider fauna of any given community. In the present study, pitfall trapping, sweep netting and jarring methods were used to sample spiders from three different sites within Nnamdi Azikiwe University, Awka, Nigeria. Sampling was done once every month for twelve months (April 2017 to March 2018). Out of the 680 individuals in 17 families caught, 63 % was by pitfall trap, 20 % and 17 % were respectively from sweep net and jarring method. At p<0.05, the sampling effort of pitfall trap was significantly better than the other two methods. Pitfall trap also recorded all taxonomic groups found in the study except Sparassidae and Uloboridae that were exclusively caught by sweep net and jarring methods respectively. Zodariidae, Ctenidae, Pisauridae, Pholcidae and Nesticidae were exclusively recorded by pitfall trap. There was a record of catch for all the three sampling techniques in all the twelve sampling attempts. Based on our finding, several sampling methods should be used in community survey for more reliable information on species richness, distribution and abundance. [ABSTRACT FROM AUTHOR]

Females of the feather-legged spider Uloborus plumipes invade, and compete for, each other's orb webs. In the context of these competitive interactions the question arose how the spiders communicate. Since substrate-borne vibrations are the most important component of the sensory environment of web-building spiders, we investigated vibratory movements that might serve as signals of communication. Three behaviors were found to be associated with female–female contests and to cause propagating vibrations in the spider webs: thread pulling, abdominal trembling, and web shaking. While thread pulling and abdominal trembling were also observed when prey insects were caught in the webs, web shaking occurred only in response to the presence of a competing conspecific. Caused by flexing of the first legs and a vigorous rotary movement of the opisthosoma, web shaking creates a short burst of strong oscillations of the orb web. This behavior always elicited a behavioral reaction by the competitor and may serve as an intraspecific signal in the mutual assessment of competing spiders. We suggest that web shaking communicates resource holding potential in U. plumipes . [ABSTRACT FROM AUTHOR]

Spider webs are a good example of how phenotypic traits can be adjustable to the physical structure of the environment. Orb-web spiders of the family Uloboridae sometimes form aggregations inside webs of other spider species. In the present study, we focused on the system of Uloboridae associated with webs of the spiderAglaoctenus(Lycosidae). Because of the conformation ofAglaoctenuswebs, the direction of prey flow in the central and peripheral positions of the Uloboridae aggregations is vertical and horizontal, respectively. The inclination of Uloboridae orb-webs, in relation to the ground, tends to be closer to horizontal in the centre and vertical in the periphery, whereas other characteristics of the orb-webs and spiders do not differ between the positions. Structural differences between centre and periphery were not enough to explain the inclination pattern of the orb-webs, at least regarding the method we used to measure the micro-habitat structure in this study. Our results support the view of intraspecific variability in orb-web inclination as a case of foraging optimisation strategy and, possibly, of adaptive plasticity. [ABSTRACT FROM AUTHOR]

Aim Remote islands are known for providing spectacular examples of adaptive radiation, with ecological divergence across a lineage giving rise to multiple species, each specialized for a particular niche. These isolated environments also provide some of the best examples of recent colonization, often human-mediated, with a single generalist taxon distributed over vast regions. Highlighted by this dichotomy is a tendency of taxa to become more specialized over time. The current study focuses on two spider taxa (family Uloboridae) each occupying a broad range of habitats: Tangaroa tahitiensis in the Austral and Society islands of French Polynesia and Daramulunia gibbosa in Fiji. We ask whether the generalist tendency of each is associated with recent colonization of widespread species or, rather, maintained over extended evolutionary time. Location South Pacific: Fiji (18° S, 175° E), Society (18° S, 150° W), and Austral (23° S, 150° W) archipelagoes. Methods Mitochondrial COI and nuclear 18S rDNA were sequenced and analysed using maximum likelihood ( RA x ML) and Bayesian approaches with concurrent divergence dating calibrated with a general arthropod molecular clock. Ancestral ranges were reconstructed independently for French Polynesia and Fiji ( RASP). Results While both T. tahitiensis and D. gibbosa occur broadly from sea-level to cloud forest, each has a separate and ancient origin within their respective archipelagoes, the pattern of colonization matching the geographical arrangement of the islands. Main conclusions Populations of two spider species, T. tahitiensis in the Australs and Societies and D. gibbosa in Fiji, are extreme generalists with broad physiological tolerances throughout their respective ranges. Yet, every population displays single island endemism and deep genetic divergences between islands indicating a long history on individual landmasses, a finding that contradicts the tendency for organisms to show increasing specialization associated with endemism. [ABSTRACT FROM AUTHOR]

We describe a new genus and two new species of the spider family Uloboridae Thorell, 1869 from south-eastern Brazil. Uaitemurigen. nov. can be distinguished by the peculiar shape of the opisthosoma, the presence of flattened setae on the patella and tibia of all legs, the flattened embolus, presence of a tegular plate in the male palpus, and female genitalia with flattened copulatory ducts associated with inflated hyaline copulatory atria. The type species, Uaitemuri rupicolasp. nov., is described from males and females from lowland and montane forests throughout south-eastern Brazil. A second species, Uaitemuri demariaisp. nov., is based on a single male from a coastal forest in the state of São Paulo. Morphological and behavioural data support the monophyly of the genus and suggest it is closely related to Orinomana Strand, 1934, Polenecia Lehtinen, 1967, Hyptiotes Walckenaer, 1837, and Miagrammopes O. Pickard-Cambridge, 1870. Uaitemuri rupicola builds vertical orb webs with a spiral-free sector, as observed in some species of Araneidae and Tetragnathidae, but recorded here for the first time in Uloboridae. The pteromalid wasp Arachnopteromalus dasys Gordh, 1976 was observed attacking egg sacs in a population of U. rupicola. [ABSTRACT FROM AUTHOR]

Most spider species are solitary, and among the few social interactions among them, resource competition between females has received little attention. We discovered that females of the feather-legged spider Uloborus plumipes invade the orb webs of conspecifics and compete for webs. Following observations in the wild, intruder–defender interactions were studied in a terrarium and in controlled laboratory experiments. We found that contests for orb webs occurred spontaneously between adult females. Competitive interactions in U. plumipes were characterized by an escalation of ritualized behaviors. In 27% of the contests the winner was determined by interactions at a distance, which involved behaviors that caused vibratory signaling on the web. The remaining interactions escalated to physical contact, and in 78% of these a fight occurred between the contestants. Using multivariate logistic regression we determined the factors that predicted the outcome of the contests: (i) Web ownership did not give the defender a competitive advantage. (ii) The difference in physical size between the competing spiders was the most important predictor for the outcome of web contests. (iii) Independent of body size, the display of certain behaviors, specifically the ability to reach the hub before the contestant and the frequency of attacks, increased the probability of winning. (iv) Winning or losing a fight did not affect the chances of winning subsequent contests. The interactions reported here provide a promising approach to investigate communication in spiders and to test theoretical models of intraspecific competition. [ABSTRACT FROM AUTHOR]

A new species, Conifaber manicoba n. sp., is described based on a female from the state of Pará, Brazil. It is characterized as being the smallest uloborid female and by having the thoracic region posteriorly depressed. [ABSTRACT FROM AUTHOR]

Maternal care in spiders often involves behaviors associated with the protection of eggs and spiderlings against parasitoids and predators (including conspecifics). The females of several species have been documented to move their egg sacs away from natural enemies or to invest in active defense behaviors against web invaders, such as parasitoid wasps or araneophagic spider species, to protect their brood. In this study, we present observations of protective behavior by Uloborus sp. females carrying egg sacs. We also investigated whether brood size and female size influence female aggressive behaviors and response time against an artificial source of disturbance. Females carrying egg sacs almost immediately perceived and reacted aggressively against the artificial stimulus, whereas females without egg sacs moved away or ran to the web margins, avoiding the source of disturbance. The aggressive response was independent of clutch size and female body size, indicating that all females will risk interacting with potential agents of egg mortality. This systematic response by all females with egg sacs may be important for reducing the incidence of attack by the egg predator wasp Bathyzonus sp. (Ichneumonidae). [ABSTRACT FROM AUTHOR]

Two new species of the genus Philoponella Mello-Leitão, 1917 are described: P. ramirezi, from the Atlantic forest of the State of Minas Gerais, Brazil, and P. pomelita, from the subtropical forests of the Province of Misiones, Argentina. Relationships of these new species are discussed.

Two new species of Tangaroa Lehtinen 1967 (Araneae: Uloboridae) from the Cook Islands are described here: Tangaroa vaka n. sp. from Rarotonga, and Tangaroa pukapukan n. sp. from Mitiaro, both based on male and female specimens. [ABSTRACT FROM AUTHOR]

Behavior can provide useful traits for testing phylogenetic hypotheses, and some details of orb web construction behavior have been especially useful in characterizing higher-level groups in spiders. The cues used to guide construction behavior and behavioral responses to these cues hold similar promise, but have never been used in phylogenetic studies. Here we use several techniques to test the hypothesis that orb webs in the two major branches of orb-weaving araneomorph spiders (Araneoidea and Deinopoidea) are monophyletic, using both the cues that guide orb construction and the spiders' responses to these cues. If orb webs evolved only once, the expectation is that these traits should be similar in members of both evolutionary lines. This prediction was supported: species in the two groups use several of the same cues, and respond to them in similar ways. These cues include two identical reference stimuli for positioning sticky spiral lines; supplies of silk available in their glands that affect the positioning of sticky spiral loops; and at least one stimulus related to the size of the available space for the orb, which is used to trigger similar modifications of seven independent orb design traits. Neither group used tension-related cues to guide sticky spiral placement. These comparisons reinforce previous conclusions supporting orb web monophyly that were derived from morphological, molecular, and behavioral traits. [ABSTRACT FROM AUTHOR]

Spider silk production has been studied intensively in the last years. However, capture threads of cribellate spiders employ an until now often unnoticed alternative of thread production. This thread in general is highly interesting, as it not only involves a controlled arrangement of three types of threads with one being nano-scale fibres (cribellate fibres), but also a special comb-like structure on the metatarsus of the fourth leg (calamistrum) for its production. We found the cribellate fibres organized as a mat, enclosing two parallel larger fibres (axial fibres) and forming the typical puffy structure of cribellate threads. Mat and axial fibres are punctiform connected to each other between two puffs, presumably by the action of the median spinnerets. However, this connection alone does not lead to the typical puffy shape of a cribellate thread. Removing the calamistrum, we found a functional capture thread still being produced, but the puffy shape of the thread was lost. Therefore, the calamistrum is not necessary for the extraction or combination of fibres, but for further processing of the nano-scale cribellate fibres. Using data from Uloborus plumipes we were able to develop a model of the cribellate thread production, probably universally valid for cribellate spiders. [ABSTRACT FROM AUTHOR]

In several animals, males produce substances that block the copulatory openings and ducts of females. We investigated variation in presence of 'mating plugs' (MPs) in the spider Philoponella tingens. We studied the frequency of MPs in the wild and MP deposition and permanence in isolated females. In the field, over half of females had MPs, but all females collected without MPs were also mated. We identified two causes of MP absence in mated females: aggressive female prevention of plugging and MP loss. We suggest that future research should focus on understanding why MPs are lost in some females, the role of females in MP loss, and the fitness effects of plugging prevention and MP loss for both sexes. [ABSTRACT FROM AUTHOR]

A list of spider species recorded from the Parque Estadual Mata São Francisco, Paraná, Brazil was compiled based on 7,942 specimens, of which 2,872 are adults (36.15%) and 5,071 are juveniles (63.85%). Adults were identified as belonging to 45 families, 140 genera and 209 species and morphospecies (101 nominal species and 108 morphotypes). Forty-one species were recorded for the first time from the state of Paraná, most of them belonging to Araneidae (14), Oonopidae (4), Theridiidae (4), and Uloboridae (3). Conifaber guarani Grismado, 2004 and Oonops nigromaculatus Mello-Leitão, 1944 were recorded for the first time from Brazil. These results place Paraná as the sixth state with the highest number of records of spiders from Brazil, currently 465 species. This study increases in 10% the number of species recorded from Paraná, and the Atlantic Forest fragment becomes one of the most well sampled areas in the state, with 20% of all known species in Paraná. [ABSTRACT FROM AUTHOR]

The article presents research which showed an update in the taxonomic status of the spider genera Ariston O.P.-Cambridge as well as Siratoba Opell. Topics covered include the classification of the species under the Uloboridae family as well as the prevalence of the species in Brazil and Mexico. Also mentioned are the female genitalia characteristics of species that belong with the Siratoba Opell genera.

The article focuses on the observations of Humped spiders (Uloboridae) in Notting Hill, Victoria concerning its characteristics, mating behaviour, maternal behaviour. It mentions that the said type of spiders have no venom glands, however, they immobilise their prey by wrapping them in a silk. It says that during the mating, a male spider visits a female spider. It states that mother spider is responsible of building a spider web after its spiderlings left the egg case.

The article focuses on a research on the evolution of orb spiders and the adhesive compatibility of their prey capture threads. It describes the methodology of the research which was conducted on Hyptiotes (H.) cavatus, collected from Virginia, that have the stickiest threads and presents a comparison of primitive cribellar threads of the Deinopoidea subclade spiders with the Araneoidea subclade species. It reveals that combination of cribellar fibrils increased the stickiness of Araneus marmoreus threads and concludes that retention of the ability to spin cribellar threads in araneoids would have resulted in the formation of a functional adhesive system.

Abstract: Spiders are considered conservative with regard to their resting metabolic rate, presenting the same allometric relation with body mass as the majority of land-arthropods. Nevertheless, web-building is thought to have a great impact on the energetic metabolism, and any modification that affects this complex behavior is expected to have an impact over the daily energetic budget. We analyzed the possibility of the presence of the cribellum having an effect on the allometric relation between resting metabolic rate and body mass for an ecribellate species (Zosis geniculata) and a cribellate one (Metazygia rogenhoferi), and employed a model selection approach to test if these species had the same allometric relationship as other land-arthropods. Our results show that M. rogenhoferi has a higher resting metabolic rate, while Z. geniculata fitted the allometric prediction for land arthropods. This indicates that the absence of the cribellum is associated with a higher resting metabolic rate, thus explaining the higher promptness to activity found for the ecribellate species. If our result proves to be a general rule among spiders, the radiation of Araneoidea could be connected to a more energy-consuming life style. Thus, we briefly outline an alternative model of diversification of Araneoidea that accounts for this possibility. [Copyright &y& Elsevier]

Orbiculariae consists of two major clades: the cribellate Deinopoidea and the much more diverse ecribellate Araneoidea. It has been hypothesized that the higher diversity of Araneoidea is a consequence of the superiority of the viscid orb web. However, this explanation seems incomplete: for example, cribellate silk may perform better than viscid silk in some contexts. Here, we consider the hypothesis that the diversification of Araneoidea was facilitated by changes in microhabitat occupation behavior due to the cheaper viscid orb web. In the present work we investigate the idea that the reduction in site tenacity caused by the emergence of the viscid orb web has led to an increase in the exploration of different resources and to a greater diversification of the Araneoidea through the evolutionary time. To test this idea, we evaluated the response of one eribellate orb web spider (Zosis geniculata Olivier 1789, Uloboridae) and one ecribellate orb web spider (Metazygia rogenhoferi Keyserling 1878, Araneidae) to abrupt prey absence. The changes in site tenacity and the day-to-day investment in web silk were evaluated. Spiders with three-dimensional webs tend to exhibit greater site tenacity than spiders making orb webs. Zosis geniculata and M. rogenhoferi show similar site tenacity when prey is ample. When prey is unavailable, the tenacity of the cribellate species increases while the tenacity of the eeribellate remains unchanged, and the silk investment of both species decreases. However, this decrease in silk investment is more extensive in Z. geniculata. These results coincide with the idea that a less cosily ecribellate orb web leads to a lower tenacity and suggest that more frequent microhabitat abandonment in a context of insect radiation (Neoptera) leads to more diverse and opportunistic exploration of microhabitats that, in the long term, may be one explanation for the greater Araneoidea diversification. [ABSTRACT FROM AUTHOR]

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Feeding by uloborid spiders is unusual in several respects: cheliceral venom glands are absent; prey wrapping is extensive (up to several hundred metres of silk line) and severely compresses the prey; the spider’s mouthparts usually never touch the prey; and the entire surface of the prey is covered with digestive fluid. This paper presents observations on Philoponella vicina O. Pickard-Cambridge, 1899, which provide possible causal links between these traits. The spider begins ingesting soon after it wets the prey, gaining access to the prey’s interior through a broken cuticle that was broken during wrapping and by digestion of the prey’s membranes. The more abundant of the two types of wrapping lines is also digested, but the remaining shroud of wrapping silk is dense and filters digested prey particles. Robust setae on the palpal tarsus and the spread position of the anterior legs during feeding probably protect the spider from contact with the digestive fluid. Spiders extracted about 65% of the wet contents of the prey, but feeding was slow and involved substantial water evaporation. We propose that selection in uloborid ancestors to recover wrapping silk led to increased wetting of the prey’s surface and that compressive wrapping facilitated this wetting. These traits could have led to loss of the now superfluous cheliceral poison glands. [ABSTRACT FROM AUTHOR]

Orb-web weaving spiders depend upon the mechanical performance of capture threads to absorb the energy of flying prey. Most orb-weavers spin wet capture threads with core fibers of flagelliform silk. These threads are extremely compliant and extensible due to the folding of their constituent proteins into molecular nanosprings and hydration by a surrounding coating of aqueous glue. In contrast, other orb-weavers use cribellate capture threads, which are composite structures consisting of core fibers of pseudoflagelliform silk surrounded by a matrix of fine dry cribellar fibrils. Based on phylogenetic evidence, cribellate capture threads predate the use of viscid capture threads. To better characterize how pseudoflagelliform and cribellar fibrils function, we investigated the mechanical performance of cribellate capture threads for three genera of spiders (Deinopis, Hyptiotes and Uloborus). These taxa spin very diverse web architectures, ranging from complete orbs to evolutionarily reduced triangle webs and cast nets. We found that the pseudoflagelliform core fibers of these webs were stiffer and stronger, but also less extensible, than flagelliform silk. However, cribellate capture threads achieved overall high extensibilities because the surrounding cribellar fibrils contributed substantially to the tensile performance of threads long after the core pseudoflagelliform fibers ruptured. In the case of Deinopis capture threads, up to 90% of the total work performed could be attributed to these fibrils. These findings yield insight into the evolutionary transition from cribellate to viscid capture threads. [ABSTRACT FROM AUTHOR]

Investigates the effects of web design on the prey capture efficiency of the Uloborid Octonoba sybotides under different prey conditions in Kyoto, Japan. Comparison of the sizes of insects captured; Factors contributing to the design of spider webs; Relationship between the number of prey captured by artificial traps and number of prey per web per census.

1. The replacement of dry, fuzzy cribellar prey capture thread by viscous, adhesive capture thread was a major event in the evolution of orb-weaving spiders. Over 95% of all orb-weaving species now produce adhesive threads. 2. Adhesive thread achieves its stickiness with a much greater material economy than does cribellar thread. 3. Transformational analyses show that, relative to spider mass, adhesive orb-weavers invest less material per mm of capture thread and produce stickier capture threads than do cribellate orb-weavers. 4. The total cost of producing an orb-web that contains cribellar thread is reduced by 32% when a spider recycles its silk and another 34% when these capture threads are replaced by adhesive threads of equal stickiness. 5. The increased economy with which adhesive capture thread achieves its stickiness may have been an important factor that favoured the origin and success of modern orb-weaving spiders that produce adhesive capture threads. [ABSTRACT FROM AUTHOR]

Philoponella oweni (Uloboridae) is a facultatively communal spider found in the southwestern United States. Solitary females and communal groups of females coexist in the same habitats. Communal females are known to produce more eggs than solitary females. Communal females might acquire the energy for the production of additional eggs by one of three means: they might have a longer life span, and thus more time in which to acquire energy; web maintenance might be more efficient in a communal group; or communal females might spend more time feeding. Field data from a marked population in Arizona showed the third alternative was true. Two possible causes for the greater time spent feeding by communal females were investigated; either the communal web or group is a more efficient trap for insects, or the communal groups are located at sites where insects are more abundant. Analysis of feeding rates and sticky trap data confirmed the second alternative. Potential web attachment sites are limited in some habitats, and mortality during dispersal is very high. When potential web attachment sites are scarce more of the population is found in communal groups; when they are abundant more of the population is solitary. The pattern of dispersal and overwintering is this species suggests that females renewing a colony in the spring could be related. [ABSTRACT FROM AUTHOR]

Philoponella oweni (Uloboridae) is a facultatively communal orb-web spider found in arid regions in the southwestern United States. Within one habitat solitary adult females and communal groups of adult females coexist. This study compared the reproductive output (egg production) and reproductive success (production of live offspring) of solitary and communal females. There was no significant difference in the mean number of egg-cases produced by solitary and communal females, but communal females produced significantly more eggs per egg-case. However, communal females suffered significantly higher rates of egg-case parasitism from the pteromalid wasp Arachnopteromalus dasys. As a result, the mean number of live offspring produced by solitary and communal females did not differ. Thus, both strategies led to roughly equal reproductive success. The advantages of aggregation of adults may be significant in the evolution of social behavior in spiders. [ABSTRACT FROM AUTHOR]

Philoponella vicina O. Pickard-Cambridge 1899 rests on its orb web in a cryptic posture with its legs folded against its body. While feeding, the spider coats the entire prey with digestive fluid and changes its posture, spreading its anterior legs wide. We tested whether this change in leg position may function to protect against damage to its legs from its own digestive fluid. When we touched detached legs I with prey packages wetted with digestive fluid, more setae fell from the legs than when we applied tap water in a similar manner. In addition, intersegmental membranes were damaged by digestive fluid, but not by water. This and other uloborids may thus break their cryptic postures while feeding in order to avoid damage from their own digestive enzymes. [ABSTRACT FROM AUTHOR]

The article provides information on long broad-headed bug (spider) Mutusca brevicornis, one of the most frequently found herbivores in urban green spaces, and Adam Edmonds mentioning it as a Uloboridae-the only spider family that is without venom.

The article presents a study of the genitalia of the North American triangle-web female spider, Hyptiotes cavatus. Scanning electron microscope study of trypsin-cleaned preparations and light microscope study of saggital sections show that female genitalia of the North American triangle-web spider, Hyptiotes cavatus contain three elements: a pair of accessory glands, each associated with a spheric al reservoir whose duct opens near the vagina; a pair of copulatory openings that receive sperm from the male's pedipalpus and conduct it via convoluted ducts to openings beside the vagina; and a blind, edian vaginal invagination that is nonglandular and appears to receive a terminal projection of the male's palpus and, in this way, to aid in its alignment during copulation.