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Volume 49 Number 3

Abstract

A description of the pattern of structure and organization of the penial macrosetae was recently put forward for Gonyleptoidea Sundevall, 1833 and demonstrated to occur also in other families of Grassatores Kury, 2002, such as Assamiidae Sørensen, 1884, Epedanidae Sørensen, 1886 and Pyramidopidae Sharma, Prieto & Giribet, 2011. This set of homology hypotheses is herein called AE11 pattern. In this work, the monotypic Sri Lankan genus Eurytromma Roewer, 1949 of the family Podoctidae Roewer, 1912 (which is currently assigned to the Epedanoidea in the Grassatores) is studied. Male genitalia of Eurytromma are described for the first time and the first attempt is made to reconcile the chaetotaxy of ventral plate of podoctid species with the AE11 pattern. The podoctid genera Hoplodino Roewer, 1915, Strandibalonius Roewer, 1912 and Santobius Roewer, 1949 are also exemplified here; their set of macrosetae is described and the AE11 pattern is demonstrated to occur in all of them. Therefore, AE11 is more phylogenetically widespread in the Grassatores than previously thought. Eurytromma pictulum (Pocock, 1903) from Sri Lanka is redescribed. It is characterized by the presence of a meso-frontal stridulatory saw of denticles on the cheliceral hand and extreme reduction of mesotergal sutures. A further refinement is made on the current terminology system of cheliceral dentition of Podoctidae.

Volume 49 Number 3

Abstract

Courtship and mating behavior in the vinegaroon, Mastigoproctus tohono Barrales-Alcala ́, 2018, is an elaborate, multistep, and long-lasting procedure. It consists of four major stages: Chase and Grapple, Dancing, Generating, and Pressing, with subtle behaviors occurring within the stages. Courtship occurs during nighttime and requires on average nearly 13 hours for completion. Especially in the beginning of the courtship, females will often resist the advances of the male and even during later stages can escape and terminate the courtship. On average, wild caught female vinegaroons produce 52 young whose combined initial weight can exceed that of the female. These 1st instar free- living young share the burrow with their mother during the early activity period of the summer. The female exhibits maternal care including feeding prey that she catches to her new young. Vinegaroons have four immature free-living instars before molting to the adult. Each instar requires at least one year, and sometimes more than one year, before molting to the next instar. Adults can live up to four years during which time they never molt. Females can produce a litter of young during each of their second and third summer seasons. The usual lifespan of a vinegaroon from egg to death ranges from 7 to 9 years.

Volume 49 Number 3

Abstract

Observations of spiders’ pre-dispersal behavior can be used to answer various ecological and evolutionary questions. So far, dispersal experiments have often used air currents as a stimulating factor. Effects of electric fields on the pre-dispersal behavior of spiders have recently been discovered. Electric fields may lead to unexplained variation in results and limit comparability between previous studies. Here we aim to disentangle the roles of wind and electric fields on the passive aerial dispersal of three linyphiid spider species. Our results confirm that strong electric fields in the air elicit pre- dispersal behavior, and in combination with a light wind, facilitate dispersal (take-off). Nevertheless, even the strong electric fields employed here played a rather supplementary role in spiders’ dispersal with wind remaining the most influential factor. We recommend that studies of passive aerial dispersal should control for electric field strength but otherwise use wind as the primary stimulating factor.

Volume 49 Number 3

Abstract

The large size and slow movements of mature female Trichonephila clavipes (Linnaeus, 1767) permit observations of some seldom-studied details of behavioral processes, such as cutting and initiating silk lines, that help clarify functional morphology. Silk lines were cut after being grasped by the cheliceral fangs; but direct observation and details of cheliceral morphology showed that cutting was not accomplished mechanically, as has sometimes been assumed. Lines were probably cut by contact with an enzyme in the mouth region. Initiation of wrapping lines involved rapid, coordinated movements of the spinnerets and the abdomen that caused the spigots for these lines to brush against each other and dragline silk. The posterior lateral spinnerets were spread widely during wrapping; this behavior and the positions of spigots on the spinnerets probably serve to widen the swath of wrapping lines applied to the prey.

Volume 49 Number 3

Abstract

Spiders in the genus Argiope Audouin, 1826 often include silken structures in their webs called decorations. Here, I report on the form and frequency of the vertical or linear decorations built by A. protensa L. Koch, 1872 as based on a survey of online digital imagery. Of 124 webs in 262 images clearly showing the web, 38.7% were decorated, less than for other congeners also sampled across their geographic range. The spider lays silk strips centered above and/or below the web’s hub; however, one web appeared to have four strips arranged in a cruciate pattern. Unlike other Argiope whose decorations consist of zigzagging bands, A. protensa weaves a derived cottony decoration of jagged strips reminiscent of those in Uloboridae. Large and geographically broad surveys of spider behavior and web structure are possible using online databases of natural-history observations.

Volume 49 Number 3

Abstract

Reports of tarantulas feeding on birds are rare and were a matter of intense debate among naturalists for centuries. The first account dates from the early eighteenth century by the German naturalist Marie Sibylla Merian, and since then only a few reliable predation events have been published. We herein report on a predation event by the arboreal tarantula Iridopelma vanini Bertani, 2012 on two Southern house wrens Troglodytes musculus Naumann, 1823 in Brazil. The spider, a male, was found feeding on a young bird on a signpost made of two wooden posts, at dusk. The following day, one of the posts was removed and the spider was found feeding on a second young bird on its nest. We also update and discuss the identification of the theraphosids involved in predation events reported in previous works.

Volume 49 Number 3

Abstract

In this paper, vertebrate predation by jumping spiders (Salticidae) was revisited, taking into account incidents of this kind recently published in the scientific literature or on the internet. Our study revealed that vertebrate predation by salticids is more widespread than previously thought, geographically and taxonomically. Roughly ninety percent of all reported cases refer to predation on anurans (Hylidae and Ranixalidae) and lizards (Dactyloidae and Gekkonidae) by salticids from the subfamily Salticinae (Hyllus spp., Phidippus spp., and an unidentified species presumably related to Hasarius Simon, 1871). In the remaining cases, salticids from the subfamily Salticinae (Paraphidippus cf. aurantius (Lucas, 1833) and Phidippus audax (Hentz, 1845)) were observed attacking bird hatchlings (families Paridae and Trochilidae), weighing ’4–6 times more than the spiders. In two instances, the spiders were observed biting the hatchlings, but only in one single case, a salticid was seen feeding on a hatchling.

Volume 49 Number 3

Abstract

Scorpion venom is composed mainly of peptides and proteins and has high metabolic cost. Thus, individuals need to be economic in its use. This study aimed to evaluate the reactions of Tityus pusillus Pocock, 1893 scorpion to threats of different intensities. For the experiments, 28 males and 26 females were used; animals were gently touched five times on their mesosoma at different time intervals. Touches with five second intervals were considered as the high- intensity threats, while those with five-minute intervals were considered as the low-intensity threats. We found that scorpions, independently of sex, stung more often under high threat compared to low threat treatments. However, no significant differences in the defensive behavior of males and females were observed according to threat intensity. We can thus infer that regardless of sex, T. pusillus uses its stings and consequently venom only in situations of high threat.

Volume 49 Number 3

Abstract

Necrophagy is a feeding strategy in which animals feed on carrion; most scavengers are facultative and can also be predators or consumers. For amblypygids, necrophagy is a poorly documented phenomenon and there are literature records of individuals of three different species feeding on dead bats inside caves. In the present note, we document for the first time a necrophagic behavior in the whip spider Paraphrynus raptator (Pocock, 1902) which was observed feeding on Otonyctomys hatti Anthony, 1932 (Rodentia: Cricetidae) and a yucatan poorwill, Nyctiphrynus yucatanicus Hartert, 1892 (Caprimulgi- formes: Caprimulgidae) carrion. We made the observations inside a small chamber in an ancient Mayan temple inhabited by a group of woolly false vampire bats (Chrotopterus auritus Peters, 1856) in southeastern Mexico. Carrion consumption in P. raptator is directly related with the carnivorous feeding behavior of the C. auritus group with which they coexist.

Volume 49 Number 3

Abstract

The scattered literature on schizomid brooding is reviewed and discussed in reference to the number of eggs, number and position of young as well as the brood chamber. In addition, novel brooding observations are provided for the Neotropical species Hansenochrus tobago (Rowland & Reddell, 1979), Dumitrescoella decui (Dumitresco, 1977), Piaroa sp. and Surazomus sp.

Volume 49 Number 3

Volume 49 Number 2

Volume 49 Number 2

Abstract

Paraphidippus basalis (Banks, 1904) is a large jumping spider that occurs in the sky islands of the southwestern United States and northern Mexico. To date, P. basalis has only been incidentally reported on rosette-forming plants in the family Asparagaceae (yucca, agave, and sotol), even though the sky islands support a rich and diverse vegetation community. This apparent specialization is unusual because jumping spiders do not typically have strong associations with the plants on which they live. However, given that the ecology of P. basalis has yet to be studied, the microhabitat preferences of P. basalis remain unclear. We investigated microhabitat choice in P. basalis in the Patagonia Mountains of southeastern Arizona, to determine whether these spiders were specifically associated with rosette-forming plants. We surveyed 160 plots for jumping spiders, 80 with rosette-forming plants and 80 without. P. basalis was found only in rosette- forming plants, whereas other species of jumping spiders showed no preference for rosette or control plots. Larger rosette plants were more likely to contain P. basalis. This study provides an unusual example of host plant structural specificity in a jumping spider.

Volume 49 Number 2

Abstract

Studies of web evolution in spiders generally focus on the overall designs of webs in the field. As has been typical for dictynids and several other cribellate families with ‘‘irregular’’ webs, this study detected few discernable patterns in the field regarding the spatial organization of the highly variable, three-dimensional and largely aerial webs of the dictynid Dictyna meditata Gertsch, 1936. Nevertheless, there were three consistent sub-unit designs in the additions that spiders made to their webs in captivity, and in webs that they built from scratch in captivity: ‘‘silk ladders’’, with a cribellum line that zig-zagged between a pair of approximately parallel non-sticky lines; ‘‘twig ladders’’, with a cribellum line that zig-zagged between a non-sticky line and the substrate; and long non-sticky lines that each supported a long, slightly looped cribellum line. I suggest, using examples from dictynids and other families with long-lived, geometrically irregular webs, that this pattern of using consistent behavior patterns to add geometrically regular ‘‘modules’’, is widespread and ancient, but has often been missed due to damage and additions to webs in the field, and to lack of direct behavioral observations. Recent attempts to link web evolution to studies of spider phylogeny could benefit from a change of emphasis, focusing on the additions that spiders make to their webs, rather than on the currently common but necessarily vague characterizations of overall web designs seen in the field.

Volume 49 Number 2

Abstract

Most Brazilian yellow scorpion (Tityus serrulatus Lutz & Mello, 1922) populations reproduce by parthenogenesis, and only a few sexually reproducing populations are known. It has been suggested that the parthenogenesis in T. serrulatus is related to bacterial endosymbionts, but this hypothesis was recently refuted, so the causes of parthenogenesis in this species are still unknown. In the present study, we report parthenogenetic reproduction in females from a sexual population, either isolated in laboratory since birth or collected at juvenile stages. Twelve females collected as juveniles became adult and reproduced without contact with males (thus, through parthenogenesis) in the laboratory. Five females collected already pregnant gave birth to litters (F1) composed only of females, which is suggestive of parthenogenesis in the field. Eight F1 females from those litters subsequently reproduced by parthenogenesis in the laboratory. Another female collected already pregnant gave birth to a litter composed of males and females (F1), indicating sexual reproduction in the field. However, one F1 female from that litter reproduced by parthenogenesis in the laboratory. These results suggest that asexual reproduction is facultative in this population.

Volume 49 Number 2

Abstract

Treatment of bacterial cultures with hemolymph collected from desert hairy scorpions (Hadrurus arizonensis Ewing, 1928, Hadruridae) resulted in a time- and concentration-dependent inhibition of bacterial proliferation. The hemolymph proved effective in inhibiting growth of both Gram-negative and Gram-positive bacterial species. Incubation of E. coli bacteria with hemolymph at different temperatures (20–408C) showed that the antibacterial effects increased from 20–308C, but the hemolymph was largely ineffective in killing the bacteria at 35 and 408C. Incubation of E. coli with hemolymph at 258C for different time periods revealed that the antibacterial activities were extremely rapid and resulted in killing of bacteria within 1–2 minutes of contact. Interestingly, the hemolymph exhibited no phenoloxidase enzyme activity, hemolytic activity against sheep red blood cells, or melanization activity, which is a common mechanism of immunity among many diverse arthropods. This study is the first characterization of immune function of hemolymph from any scorpion species.

Volume 49 Number 2

Abstract

The arachnid order Pseudoscorpiones is characterized by a huge number of different mating strategies. Cheliferidae, for instance, have developed complex mating dances, including the use of the curious ram’s horn organs of males. The present study provides a detailed description of the mating behavior of Dactylochelifer latreillii latreillii (Leach, 1817), including first quantitative data for each behavioral unit, based on the analysis of laboratory video captures of individual mating ceremonies. Previous studies on mating in cheliferids have been purely qualitative, including a description of mating in a distinct subspecies of D. latreillii, D. l. septentrionalis Beier, 1932. Qualitatively, our data on Dactylochelifer l. latreillii is roughly consistent with these older observations except for some differences in the vibrating behavior of males.

Volume 49 Number 2

Abstract

Neopurcellia salmoni Forster, 1948 is a mite harvestman found throughout the forests of the west coast of New Zealand’s South Island. This species range is unusually large for the notoriously dispersal-limited Cyphophthalmi, raising the possibility of multiple cryptic species within the lineage. In order to test this hypothesis, we used scanning electron microscopy to examine a large number of individuals from throughout its range, and discovered two distinct male morphotypes distinguished by the presence or absence of dorsal glandular pores. We performed phylogeographic and population genetic analyses using DNA sequence data from the fast-evolving mitochondrial locus cytochrome c oxidase I (COI). Tree topologies revealed two well-supported clades within Neopurcellia Forster, 1948 occupying non-overlapping geographical regions of the west coast. Molecular dating indicates that these lineages diverged from each other following the Oligocene ‘‘drowning’’ of New Zealand and diversified during the uplift of the Southern Alps. The strong correlation between the evolutionary relationships of lineages within Neopurcellia and the geographic distribution of its populations indicates isolation by distance, as expected with dispersal-limited organisms; population genetic analyses confirm strong isolation of populations. However, we discovered that the distribution of male morphotypes does not follow any geographic or phylogenetic pattern. While the presence of two different morphotypes initially suggested multiple Neopurcellia species, phylogeographic analysis allowed us to reject this hypothesis. We therefore report here the first known case of male polymorphism in the suborder Cyphophthalmi.

Volume 49 Number 2

Abstract

The English counterpart of Cuvier’s Le Re`gne Animal, organized by Edward Griffith in several volumes, contained not only a translation of the French original, but also new material added by invited collaborators. The part on Arachnida, with new material contributed by George R. Gray, contained descriptions of five species of Opiliones, one of them a mite, and two of them new. There are identifications, synonymies and homonymies involved in the taxonomy of these species which are questioned herein. Gonoleptes spinipes Gray, [20 July] 1833 is a senior primary homonym of Gonyleptes spinipes Perty, [13 December] 1833. This is currently a species inquirenda in Caelopyginae, which is newly considered a subjective synonym of Metarthrodes triangularis Roewer, 1931. The latter name should stand in virtue of the senior being invalid by homonymy. Gonoleptes spinipes Gray is also a new subjective synonym of Goniosoma roridum Perty, 1833, which is in prevailing usage, which makes it a nomen protectum.

Volume 49 Number 2

Abstract

A new species, Eukoenenia sinensis, is described and illustrated from specimens collected in two forests in nearby islands in Guangdong Province, Southeast China. The genus Eukoenenia is recorded for the first time from China and it represents the second palpigrade species reported for this country after Koeneniodes madecassus Re ́my, 1950. The new species shares several morphological characters with other soil-dwelling Eukoenenia species from Africa, Asia and South America. One of the distinctive characters of E. sinensis is the presence of 6 pairs of setae (a1, a2, a3, a4 þ s1, s2) on opisthosomal sternites IV to VI, a character only shared with another five species. Eukoenenia sinensis is most similar to specimens captured from Chile and identified by Dr. Bruno Conde ́ as Eukoenenia cf. grassii; several morphological and morphometric features allow to differentiate both species. From the other four species, two can be readily distinguished by their troglomorphic characters, and the other two are soil-dwelling species that show differences in the chaetotaxy of basitarsus IV, metapeltidium, deutotritosternum, opisthosomal tergites III–VI, as well as the number of teeth in the cheliceral fingers. In addition, E. sinensis is the first palpigrade to exhibit sexual dimorphism in the number of thick setae of coxa IV.

Volume 49 Number 2

Abstract

Amblypygi is a small order of arachnids that includes the whip spiders. Like other members of the clade Pedipalpi, these arachnids are cryptic predators that use their antenniform appendages to detect prey, and spinose pedipalps for quick prey capture. To date, there is very little information on the composition of their exoskeleton despite its importance in predation and defense. Here, we performed the first analysis of a whip spider exoskeleton using energy- dispersive X-ray spectroscopy (SEM-EDS). Our studies of Phrynus marginemaculatus CL Koch, 1840 were designed to (1) determine if elemental profiles differ between instars and (2) determine if and how elemental profiles of whip spiders differ from other closely related arachnids. We found the whip spider exoskeleton to contain several trace metal elements including calcium, magnesium, manganese, potassium, sodium, and zinc. The diversity and abundance of trace elements is relatively low throughout the exoskeleton of 2nd instars but increases in adults. In particular, the chelicerae and pedipalps are well reinforced with several metal elements, most notably calcium and zinc, which are also present in the tarsal claws. A similar elemental distribution is known for adult whip scorpions (Thelyphonida). In P. marginemaculatus, these metal elements are similarly present in adult exuviae. The elemental enrichment of the whip spider exoskeleton is comparable to that present in other members of the Pedipalpi and Tetrapulmonata, reflecting a relatively conserved profile for the few species that have been examined.

Volume 49 Number 2

Abstract

In previous studies, the ‘‘cocoon’’ webs built by spiders of the genera Cyclosa Menge, 1866 and Allocyclosa Levi, 1999 under the influence of Polysphincta spp. wasps resembled molting webs built by unparasitized spiders; this behavioral manipulation was associated with increased concentrations of the molting hormone ecdysone. The present study documents an additional aspect of the cocoon webs of Allocyclosa bifurca (McCook, 1887) built under the influence of the wasp Polysphincta gutfreundi Gauld, 1991. Molting webs were more likely to have an associated barrier web than were prey capture orbs; and cocoon webs were even more likely to have barrier webs. The similarity between molting and cocoon webs accords with previous indications of ecdysone use by the wasps. The accentuation of molting web traits in the cocoon webs (also seen in other species) implies that the wasps manipulate the spiders using mechanisms other than simply replicating hormonal stimuli involved in normal molting.

Volume 49 Number 2

Abstract

Accumulated studies have revealed that spiders, which are believed to be true predators, also feed on various plant materials such as pollen, nectar, and stigmatic exudate. Hereby, we report observational cases of fermented tree sap feeding by four spider species, namely Sinopoda forcipata (Karsch, 1881) (Sparassidae), Otacilia komurai (Yaginuma, 1952) (Phrurolithidae), Weintrauboa contortipes (Karsch, 1881) (Pimoidae), and Doenitzius cf. peniculus Oi, 1960 (Linyphiidae), in deciduous forests in Japan. This is the first report of spiders feeding on fermented sap, and also the first report of plant material consumption in the families Sparassidae, Phrurolithidae, and Pimoidae.

Volume 49 Number 2

Abstract

In spiders, intersex communication during courtship is essential to avoid the risks of cannibalism due to lack of specific recognition. Parabatinga brevipes (Keyserling, 1891) is a Ctenidae spider with a distribution from Colombia to Uruguay. This study is the first to describe the sexual behavior of P. brevipes, and the fourth reported in the family. We introduced males to females in a cage and recorded their courtship and copulation behavior. Males began courtship after touching female silk, performing Leg-tapping of legs I and Palpal movements. We observed ten copulations that usually occur vertically, in the copulatory position reported for other ctenids, with the male on top of the female, oriented in opposite directions. Copulations usually involve the insertion of one male palp in a single female’s genital opening and finish with the pair dropping from the vertical position. These sexual behaviors are compared with reports of other species in the family.

Volume 49 Number 2

Abstract

Jumping spiders are known for complex courtship displays with both visual and vibratory components, but increasing evidence shows they also use chemoreception in intraspecific communication. We conducted two experiments using Habronattus pyrrithrix (Chamberlin, 1924) to assess male response to substrate-borne or airborne chemical cues produced by virgin females. First, we tested the effect of substrate-borne cues by allowing males to inspect two pieces of filter paper that had either been exposed to a female (thus covered in silk and/or excreta) or not (control). Second, we used a Y-tube olfactometer to test male response to female airborne cues versus a no-odor control in the absence of substrate- borne cues. Males responded to substrate-borne cues (spending more time traversing and palpating female-treated filter paper compared with the control) but did not respond to airborne cues alone. Together, these experiments suggest male H. pyrrithrix may use contact chemical cues from  female silk to locate or assess females.