Female Silk Research Articles

The wolf spider Pardosa milvina varies silk deposition in response to self and same‐sex conspecific silk

AbstractSilk is an important communication medium for spiders with roles in species recognition, sex identification, and mating status assessment. Spiders may benefit by discriminating between their own or another same‐sex conspecific's silk. Silk‐mediated self‐recognition could allow spiders to identify areas that they have previously visited, competitively block silk advertisements from sexual rivals or minimize redundant signaling in an area. Silk deposition behavior may also be contingent upon silk cues detected from same‐sex conspecifics. We tested if males and females of the wolf spider Pardosa milvina show different silk deposition patterns when encountering their own silk versus the silk of another spider of the same sex. Using a within‐between‐subjects design, we quantified male and female deposition of three silk types: draglines, cord silk, and attachment disks on substrates containing either their own silk or the silk of an adult same‐sex conspecific (N = 23 males, 28 females). Both males and females significantly increased dragline and cord silk deposition on substrates containing conspecific rather than their own silk with males producing more cord silk than females. Males significantly increased attachment disk deposition on conspecific male silk compared to their own while females showed the opposite response, decreasing attachment disk deposition on conspecific female silk. Both male and female P. milvina can recognize their own silk, but we found significant qualitative and quantitative sex differences in silk deposition suggesting sex‐specific functions for attachment disks compared to cord or dragline silk.

Glamorized Exploitation: Visual Images of Meiji-Period "Factory Girls" (jokō).

The cover image of this issue of Technology and Culture is a collage crafted from two figures in this essay. On the right side of the image is a detail of a black and white photograph from around 1900 of female silk mill workers () juxtaposed on the left with detail of a color woodblock print from 1877 depicting a mock-up of the Tomioka silk mill featured in an industrial exposition staged that year in Tokyo (). The collage was composed by reversing the two figures to create a dynamic "V" designed to draw the viewer's eye from left to right and, by implication, from the glamorized rendition of silk mill work in the woodblock print to a more real-world photograph documenting actual working conditions in a silk mill. This essay provides a socio-historical matrix for, and critical analysis of, representative visual images of sericulture and silk mills.

Identification of Cuticular and Web Lipids of the Spider Argiope bruennichi

Emerging evidence shows that the cuticular and silk lipids of spiders are structurally more diverse than those of insects, although only a relatively low number of species have been investigated so far. As in insects, such lipids might play a role as signals in various contexts. The wasp spider Argiope bruennichi has probably the best investigated chemical communication system within spiders, including the known structure of the female sex pheromone. Recently we showed that kin-recognition in A. bruennichi could be mediated through the cuticular compounds consisting of hydrocarbons and, to a much larger proportion, of wax esters. By use of mass spectrometry and various derivatization methods, these were identified as esters of 2,4-dimethylalkanoic acids and 1-alkanols of varying chain lengths, such as tetradecyl 2,4-dimethylheptadecanoate. A representative enantioselective synthesis of this compound was performed which proved the identifications and allowed us to postulate that the natural enantiomer likely has the (2R,4R)-configuration. Chemical profiles of the silk and cuticular lipids of females were similar, while male cuticular profiles differed from those of females. Major components of the male cuticular lipids were tridecyl 2,4-dimethyl-C17-19 alkanoates, whereas those of females were slightly longer, comprising tridecyl 2,4-dimethyl-C19-21 alkanoates. In addition, minor female-specific 4-methylalkyl esters were detected.

Cylindrical Glands and Egg Sac Silk of Giant Wood Spider, Nephila pilipes

Different types of silk glands are located inside the abdomen of spider. Three pairs of cylindrical glands are developed in female giant wood spider, Nephila pilipes. In the present study, attempt have been made to explain the anatomy and histology of cylindrical glands and details of its spinning field with the help of scanning electron micrograph (SEM). The microscale topology and surface nanostructure of egg sac silk threads was studied with advance techniques of atomic force microscopy (AFM).It is concluded that, in female spider, cylindrical glands and egg sac silk produced by them plays a very important role in successful perpetuation of species. Roughness analysis of egg sac silk suggested that this biomaterial has high toughness that may be suitable for dissipating high amounts of mechanical energy. This silk is having high and stable mechanical performance. Hence, successful large scale production of this beautiful and strong, naturally pink colored spider silk will definitely open a new gate in textile sector.

Males respond to substrate-borne, not airborne, female chemical cues in the jumping spider, Habronattus pyrrithrix (Araneae: Salticidae)

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.

No strings attached: description of the sexual behavior in the Neotropical spider Parabatinga brevipes (Keyserling, 1891) (Araneae: Ctenidae)

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.

Males of a Neotropical spider adjust prey‐gift construction but not mate search in response to sperm competition

AbstractIn scramble competition mating systems, males do not guard females and females usually mate polyandrously, leading to high levels of sperm competition. Mathematical models predict that males facing sperm competition can either decrease or increase their reproductive effort. To test how male reproductive responses vary according to sperm competition risk, we ran two experiments using the polyandrous gift‐giving spiderParatrechalea ornata. First, we tested whether males prefer substrates containing silk of unmated females than substrates containing silk of once‐mated females, competitor males or without silk. Males spent more time on substrates containing silk of females but showed no preference for unmated females, which indicates that males may optimize mate search by prioritizing substrates containing cues of potential mating partners. The lack of preference for unmated females suggests that males cannot detect female mating status from silk or that the costs of searching preferentially for unmated females are high in the field. Second, we tested whether males adjust prey‐gift construction when facing sperm competition risk. Experimental groups (substrate containing silk of an unmated female and silk of another malevs. substrate containing only silk of an unmated female) did not differ in the frequency of gift construction, latency to gift construction and number of flies added to the gift. However, males facing sperm competition risk constructed gifts with less silk, suggesting the occurrence of a less evident form of male mate choice based on differential allocation of resources to prey‐gift. Additionally, given the trade‐off between investing in prey‐gifts quantity or quality, a lower silk investment should enable males to increase the number of gifts constructed and the number of courted females. Taken together, our results indicate that males detect female and male pheromones on substrate and adjust the construction of prey‐gifts in response to apparent sperm competition risk.

Chemical Species Recognition in a Tetragnatha Spider (Araneae: Tetragnathidae).

Much of our knowledge regarding the role of chemicals in species recognition in arthropods is based on a few taxonomic groups, predominantly insect pest species. To investigate the chemical underpinnings of species recognition cues in other arthropods, we conducted mate choice experiments and analyzed the chemical profiles of two species in the long-jawed spider genus Tetragnatha from allopatric populations across two different continents. In two separate bioassays, in which male T. extensa spiders were presented with either web silk or extracts from the silk of conspecific and heterospecific females, males consistently chose the silk or silk extract of conspecific females over those of heterospecifics. We examined the chemistry affecting this response using gas chromatography/mass spectrometry to analyze silk and whole-body extracts of the spiders. The major compounds in the extracts were identified as long chain aliphatic methyl ethers. The chemical profiles of the two species differed: the T. extensa profile consisted of 12,20-dimethylnonacosyl methyl ether (A), 8,14,20-trimethylnonacosyl methyl ether (B), and 6,14,20-trimethylnonacosyl methyl ether (C), while the profile of T. versicolor consisted of B and 14,20-dimethylnonacosyl methyl ether (D). Within each species, chemical profiles of females and males did not differ. Our results suggest that these methyl ethers are involved in species recognition of Tetragnatha spiders. This is the first study to propose compounds involved in species recognition in spiders.

Dragline silk reveals female developmental stage and mediates male vibratory courtship in the nuptial gift‐giving spider Pisaura mirabilis

AbstractMale mate choice likely occurs when costs are associated with courtship or mating. For example, when males produce continuous vibrational signals, provide nutritious nuptial gifts, or are likely killed during mating, they should assess female developmental and reproductive state. Substrate‐borne vibratory courtship signals are very common in spiders serving species recognition, suppressing the female's aggression towards the male, or signalling individual quality. Males of the nursery web spider, Pisaura mirabilis, usually offer a prey item wrapped in silk as a nuptial gift to the female; the gift is commonly produced prior to female contact. When touching dragline silk deposited by a female, males tremulate their opisthosoma presumably reacting to chemical cues. Courtship energy expenditure and resource transfer should select for selective male mating decisions in this species. We hypothesized that male P. mirabilis differentiate between developmental stages of the female (sub‐adult vs. adult). Differential courtship towards virgin and mated females was not expected since females forage for nuptial gifts and might continuously signal receptivity. To test this, vibrational courtship signals of male spiders towards draglines of sub‐adult, adult unmated and mated females were recorded with a Laser Doppler Vibrometer. We found that males were less likely to perform vibrational courtship and produced less pulses when contacting silk of sub‐adult females, compared to silk produced by adult females, while their reaction towards silk of unmated and mated adult females did not differ. Reduced courtship in response to sub‐adult female silk seems beneficial since it reduces energy expenditure in the face of a not yet reproductive female. When vibratory courtship occurred, the temporal patterns and dominant frequencies of the males' vibratory signals were similar, regardless of female developmental stage or mating status. Such stable patterns suggest a role in species recognition already at a distance without direct physical contact and in reducing female aggression.

Condition-dependent differences in male vibratory pre-copulatory and copulatory courtship in a nuptial gift-giving spider

Condition-dependent secondary sexual traits and signals are often crucial for mate choice decisions. Nuptial gifts, provided by the male to the female during mating, may represent an indicator of male condition, especially if production of the gift is energetically costly. Additionally, other signalling modalities may well play a role in mate choice in such systems. Females of the nursery web spider Pisaura mirabilis preferably mate with males that provide a prey item wrapped in silk. Apart from the nuptial gift, vibrational signals employed during courtship and mating may reveal additional information about male condition. We tested condition-dependence of male vibrational signals of well-fed versus starved males, when in contact with female dragline silk and during mating trials. Our results show that vibrational signals are produced in P. mirabilis, both during pre-copulatory courtship and during copulation. Male courtship signals were condition-dependent: males in good condition initiated signalling earlier and emitted more vibrational pulses than poor-condition males. They were also more likely to be accepted by the female for copulation. We additionally identified vibrational signals during copulation. These signals were different from pre-copulatory courtship vibrations but did not differ between the treatment groups. This study shows that vibrational communication plays an important role before and during copulation in P. mirabilis. It sets the stage for further experiments on spider biotremology associated with nuptial gift giving behaviour.Significance statementMale courtship behaviour can indicate a male’s condition and quality and be subject to female mate choice. Vibrational communication during mating plays a crucial role in many animal species. Spiders are known to be extremely sensitive towards vibrations, and there is evidence that vibratory signals are also used during courtship. Here, we study the nuptial gift-giving spider Pisaura mirabilis in which courtship entails providing a nuptial gift by the male to the female. The gift quality determines on the probability and duration of mating. We investigated the role of vibrational behaviour in this species by standardizing nuptial gifts. Our study demonstrates that vibratory signals comprise information about the male’s condition, that signals are also produced during mating and that courtship and copulatory signals are strikingly different. We suggest that vibrational communication provides important condition-dependent traits for female mate choice in addition to the nuptial gift.

Silk‐ and volatile‐based male mate choice in the genital plug‐producing spider

AbstractFemale mating history can have a strong effect on male fertilization success. Although males often prefer to mate with virgin females, they often also engage with mated females. As the intensity of sperm competition can differ among mated females, males are expected to evolve means to identify their status. In spiders, males often use female silk to gather information about female quality. Males of many spider species deposit mating plugs into female genitalia to hinder further copulations. We tested whether males of the foliage‐dwelling, plug‐producing spider Philodromus cespitum, which is an important natural enemy of pests, discriminate between females of different mating status and whether they can determine the extent of genital plugging in mated females solely on the basis of cues gained from deposited female silk. We presented males with draglines of females that varied in either mating status (virgin vs. mated), the extent of plugging (small vs. big plug), or the age of the plug (fresh vs. old plug) and examined their mate preferences. Additionally, we tested whether males were attracted to volatile cues produced by female bodies. Our experiments revealed that males preferred draglines of virgin females to those of mated females, and mated females with small plugs to those with large plugs. They were also attracted to female volatile cues. This study suggests that males are able to extract fine‐scale information on mating status from female draglines.

Promiscous female Euxesta eluta derive nutrients for ovarian development by expelling and consuming ejaculates.

Seminal gifts range from important material donations to items that provide little direct benefit to females. Promiscuous, female silk corn flies Euxesta eluta expel and consume male ejaculates immediately after mating. The evolution and function of this peculiar behavior are currently unknown. We performed a series of experiments aimed to: determine if females under different dietary regimes derive nutrients or water for survival and/or reproduction from ejaculate consumption, if males suffer a fitness cost from supplying females with ejaculates, and if females prefer to mate and/or are more likely to store sperm from well fed than nutritionally stressed presumably inferior males. Experiments revealed that protein deprived E. eluta females derive nutrients for ovarian development through consumption of ejaculates of protein fed males. No seminal products affecting survival appear to be transferred in the consumed ejaculate. However, ovarian development, in contrast to testes growth, occurs in detriment of longevity. Females preferred to mate with protein fed males, yet sperm retention in spermathecae was extremely rare after a single mating. This finding suggests that females could be exerting post copulatory control. A key question that remained to be addressed for the understanding of this puzzling and promiscuous mating system is what ecological factors or male traits drive females to retain sperm from one or several males in order to achieve and/or maximize fertilization potential.

Does silk mediate chemical communication between the sexes in a nuptial feeding spider?

Chemical signals play a crucial role in reproduction as a means for locating mates and/or gaining information about their quality, ultimately affecting mating system dynamics and mate choice. In spiders, one of the potential sources of chemical signalling is silk. However, while female silk is known to attract mates and/or elicit courtship, due to sex-specific roles in mate searching, male silk-related signals are often neglected. In the hunting spider Pisaura mirabilis (Pisauridae), both sexes leave silk draglines during movements while males additionally use silk to wrap nuptial gifts (food donations to females at mating). We explored the potential for both silk types (draglines and gift silk) to release signals and tested the hypothesis that chemical compounds bound to gifts’ silk serve to elicit female attraction. We conducted behavioural choice assays for dragline and gift silk, and their putative transmission mode (airborne or contact) by testing (i) male and female attraction towards draglines of the opposite sex and (ii) female attraction towards gift silk. Whereas males were attracted to female draglines (contact cues), females did not respond to male silk of any type. We suggest that females use draglines for advertisement to secure copulation and foraging of nuptial gifts. If these signals ease male mate searching, attractive male draglines are unnecessary. Overall, males may not invest in chemical stimulation but rather exploit female foraging interests through gift giving. Alternatively, they may release signals that prime other female sexual behaviours or towards which females may have evolved resistance. Animals commonly use chemical signals to communicate during reproduction, and spiders have the potential to release such signals from their silk. We investigated whether two silk types, draglines released during movements and silk covering male nuptial gifts (prey offered to females at mating) are attractive to the opposite sex in a hunting spider. While males were attracted to female draglines, females did not respond to male silk of any type. Females may be using silk to advertise themselves to secure matings and food through reception of nuptial gifts. If males can successfully locate females, attracting females through draglines may be unnecessary. The finding that males do not release attractant signals in the silk cover of their nuptial gifts further suggests that rather than attempting to increase their attractiveness by using chemical stimulation, males may be uniquely exploiting females’ interest in food through gift giving behaviour.

Portrait of a Woman in Silk: Hidden Histories of the British Atlantic World by Zara Anishanslin

Reviewed by: Portrait of a Woman in Silk: Hidden Histories of the British Atlantic World by Zara Anishanslin Dale Bauer (bio) Portrait of a Woman in Silk: Hidden Histories of the British Atlantic World zara anishanslin New Haven: Yale University Press, 2016 421 pp. This is an impressive, meticulously detailed narrative of the "imperial power" of silk designing, weaving, and consumption. Zara Anishanslin divides it into four major parts based on the narratives of the silk designer, the master weaver, the silk wearer in the United States, and finally, the painter who captured her in her luxurious silk. Then Anishanslin documents the history of these figures before she analyzes the social and historical context in which each worked and lived. (Her images include some amazing documents of eighteenth-century life—from the watercolors of silk design to the pictures of the banyan and of the painter Robert Feke's other portraits.) This book begins with the wide-ranging London silk industry, whose powers signify the range of cultural force often against the French but also operate as a sign of luxury in America (5). The one portrait of the silk wearer generates a history of consumption in a "transatlantic network" of a singular object with vast cultural meanings (10). Anishanslin's method illustrates the US silk explosion as a story of the political and material exchanges between England and the United States starting before the Revolutionary War. Particularly striking in the first part—on the designer of botanically inspired silk—is the author's focus on the status of a female silk designer, especially one who had no training in silk design but who had an expansive knowledge of the landscapes and botanicals of her day, as well as the exchanges of botanicals between Britain and America. As a clergyman's daughter, Anna Maria Garthwaite, silk designer, was invested in designing flowered silks. Garthwaite had created a "cutwork landscape" in 1707, [End Page 223] which illustrated her fine artistic skills and which meant that she used these skills in creating intricate designs (often of botanical images) (42, 61). These landscapes enhanced the "visual effects" of her designs (44). She advanced the rococo fashions of British culture, which extended to America, demonstrating the global trade of the eighteenth century. Spitalfields silk itself was "a thing of fashion" (129), and fashion itself illustrated the imperial power that Britain wielded. Garthwaite was also known for her flowered silk designs that highlighted the ordering of natural landscape and botanicals. In so doing, she created "memorable fashionability" and distinctive art instead of producing actual gardens or a family (69). Simon Julins, master weaver, of the comfortable "middling culture," is the subject of part 2 (110). Julins was an expert at weaving silk flowers, a particularly exacting task. Silk weavers like Julins worked in "proto-industrial spaces" in guilds that had great political leverage (131). Working in such guild memberships, as Julins did, gave male artists clublike atmospheres where they could work with their own journeymen (135). His studio offered Asian and botanical silks to buy, which responded to Americans' interest in sericulture, and, as Anishanslin has it, Garthwaite's and Julins's skills were also fashion forward (109). This chapter also charts the riots about cloth costs—whether in cheaper cottons and calico or expensive wools and silks—along with arguments about the weavers' status as journeymen or master weavers (137). America also sent silk to English markets as a form of competition while additionally showing how American raw silk could compete with England's (141, 157). Perhaps more important, American women produced silk, even writing treatises on silkworms (159). Part 3 is the most exciting section, on Anne Shippen Willing, whose decision to wear this damask flowered silk in 1746 was both a consumer and a cultural choice, showing her inclusion in a wealthy mercantile family. "Distribution, consumption, and display" of such silk meant that the British Atlantic world—in its global dimensions—had cultural influence even as America was demonstrating its trading in other commodities. Anne Willing's "sociable performance" in the four portraits she had of herself showed the force of urban transatlantic exchange, illustrating along with the Willings' wealth (partly from...

The Silk Industries of Medieval Paris: Artisanal Migration, Technological Innovation, and Gendered Experience by Sharon Farmer

Reviewed by: The Silk Industries of Medieval Paris: Artisanal Migration, Technological Innovation, and Gendered Experience by Sharon Farmer Daryl M. Hafter (bio) The Silk Industries of Medieval Paris: Artisanal Migration, Technological Innovation, and Gendered Experience. By Sharon Farmer. Philadelphia: University of Pennsylvania Press, 2016. Pp. 368. Handcover $69.95. This splendid book is a model of history and technical writing. Its author, a highly respected historian and scholar of textile technologies, seeks to verify the long-surmised existence of a silk industry in medieval Paris. The extreme lack of documentation has kept historians from learning about silk making in medieval Paris before now. But samples of woven and embroidered silk in museums and notes in royal archives labeled "silk of Paris" kept alive the idea that a silk industry had existed. Farmer has used the Livre de métiers, tax rolls from the twelfth-fifteenth centuries, royal and aristocratic budget books, as well as examples of luxury silk products to reconstruct a vivid portrait of this industry. In addition, she has supplemented her archival research with a thorough study of the period. Farmer's intent is not only to show that twelfth-fifteenth century Paris had a flourishing silk industry, but that it was fostered by immigrants from Italy and other countries, some of whom became thoroughly integrated into French society. In the course of doing so, she paints a broad picture of silk in Western Europe, the consumption patterns of wealthy individuals, and the unusual opportunities for women working in the Paris silk trade. To help readers who are not familiar with its technology, Farmer gives the clearest and most helpful description of the trajectory of silk from cocoon to woven cloth that I have seen. She leaves us with an understanding of the hierarchy of mercers selling the textile, to highly skilled weavers of soie de Paris and velvet, to female throwsters (spinners) preparing the thread for bobbins. What is most extraordinary about her work is her ability to extrapolate economic relations and lived experience from the small clues in the sources. Though there are only traces, the author suggests that some mercers established their own workshops. From the tax rolls, she recreates neighborhoods of various kinds of silk workers, moneylenders, and mercers who sold the cloth. From guild statutes she concludes that spinners stole from the silk yarn they processed, and pawned it to pay for daily necessities. Since these thread makers lived closest to the Jewish lenders, it was natural to use them. Besides, the Jewish lenders were mostly women who imposed easier terms than the Lombard lenders. From a few records of [End Page 475] throwsters impregnated by Lombard lenders, Farmer deduces that women were more likely to borrow from the Jewish women because while Lombards (accused of half the rapes in Paris) left wives at home, the Jews lived in families. Not only were Jewish women able to participate in the economy, Farmer estimates that there were 1,400 other women manufacturing silk. Of the 241 women listed on tax rolls with their profession, 26 percent were in silk. Even though most were spinners with incomes too low to appear on tax rolls, in general female silk workers' incomes were higher than those of other women working at textiles in northern France and the Lowlands. Chapter 1 sets the stage by showing medieval Paris as a highly cosmopolitan center of royal residence and administrative officials who stimulated silk and other luxury trades. Chapter 2 details the manufacture of silk, and the important role of Lombard merchants in providing raw silk. The mostly female makers of prestigious "narrow goods" and the less-prestigious all-female guild weaving veils together constituted some forty-five weavers. Chapters 3 and 4 show that many mercers came from Italy, a few from Germany and the South of France. Their entrance to Paris is important because it helps to substantiate Farmer's claim that the technology was imported into Paris. As Chapter 5 indicates, silk industries through time have always been founded by skilled workers migrating. The mercers coming to France presumably brought such workers from northern Italy, enabling mercers to establish their own ateliers. Aware that her method of...

Context‐ and State‐Dependent Male Mate Choice in a Sexually Cannibalistic Spider

AbstractHigh male mating investment may favor selection on male mate choice particularly if females vary in quality. Terminal investment strategies constitute a maximal mating effort and have evolved independently in the absence of paternal investment in several spider taxa including the genus Argiope. To test for male mate preferences in the above context, we used the sexually cannibalistic spider A. bruennichi. We varied male state (mating status and post‐maturation age) as well as the competitive context and quantified male mate choice decisions between females of different states and developmental stages in binary choice tests. We found an overall adaptive preference for the virgin against the mated female regardless of male mating state. Furthermore, we demonstrated that older males paid more attention to female fecundity‐related traits than to mating status. In a second set of experiments, we offered males a choice between a virgin and a subadult female and varied the competitive context which had no effect on male decisions. Curiously, a preference for the virgin adult female was only apparent after exclusion of females that matured <3 d prior to the test. Repeated tests of males supported the hypothesis that males do not distinguish between a freshly matured virgin female and a subadult female. Our results show that male spiders execute mate choice based on information collected from female silk strands and that they integrate their own state into mating decisions.

Disruption of the chemical communication of the European agrobiont ground-dwelling spiderPardosa agrestisby pesticides

Lycosid spiders are among the most abundant and diverse insectivores occurring in all agroecosystems. Certain pest management practices, such as the application of pesticides, can disrupt their role in insect pest control. Therefore, understanding the effects of pesticides, including sublethal effects, is essential for the assessment of chemical effects on beneficial arthropods. We investigated the sexual chemical communication of the beneficial agrobiont spider Pardosa agrestis and its disruption by two widely used pesticides, the glyphosate-based herbicide Roundup and the pyrethroid-based insecticide Nurelle D. A two-choice olfactometer and Y-maze were used to study the effectiveness of female airborne and dragline pheromone cues and the disruptive effect of the pesticides. Males of P. agrestis did not locate females via airborne cues, but were very receptive to female dragline silk and male dragline silk. When both female dragline silk and male dragline silk were provided at the same time, the males preferred female silk. Pesticide treatments significantly affected the male ability to follow female cues deposited on dragline silk. The 3-h residues of both Roundup and Nurelle D significantly disrupted the male ability to follow female cues deposited on dragline silk. Treatment by 48-h residues significantly disrupted the male ability only in the case of Nurelle D. Our results demonstrate that pesticides reduce the ability of male spiders to search for a mate due to the disruption of the male's ability to detect the silk cues of the female.

Influence of ambient temperature on efficacy of signals produced by femaleSchizocosa ocreata(Hentz, 1844) (Araneae: Lycosidae)

Abstract The ambient temperature of an environment has potential to influence many aspects of the behavior and physiology of small-bodied ectotherms, including brush-legged wolf spiders Schizocosa ocreata (Hentz, 1844) (Araneae: Lycosidae). Temperature varies significantly, and often unpredictably, in their habitat throughout the spring breeding season, and is known to influence male Schizocosa courtship behavior. Currently unknown is what effect fluctuations in ambient temperature alone might have on critical, non-behavioral sexual signals such as female silk and chemical cues. We collected cues from mature, virgin females and subjected each sample to one of three thermal treatments (40°C, 20°C, or -12°C), at constant humidity. We presented treated female cues to mature males and recorded male response across treatment types as a behavioral indicator of signal degradation. There were no significant differences across treatments in the frequency or duration of male behaviors, including critical courtship ...

Long-Term Persistence and Water Resistance of Female Sex Cues in the TarantulaEupalaestrus weijenberghi(Araneae: Theraphosidae)

Summary The presence of pheromones has been reported for several spider species but their persistence in field conditions has scarcely been studied. We test the activity and persistence of female sex cues outdoor in the tarantula Eupalaestrus weijenberghi (Thorell, 1894), using male courtship as an indicator of cue attraction. We studied female silk fields in two conditions: protected and exposed and in both we found a long persistence of sex signals, up to 55 and 46 days, respectively. We discuss the nature and adaptive significance of these cues.

FemalePardosa milvinawolf spiders increase silk advertisements when in the presence of silk from courting males

Abstract Female wolf spider silk is known to elicit searching and courtship behavior among adult males, however variation in the types of silk females deposit, the context in which it occurs, and the role of male silk in courtship displays and female responses has rarely been examined. We measured male Pardosa milvina (Hentz 1844) silk deposition while performing courtship displays. We then examined whether female silk deposition changes when encountering silk produced from a courting rather than a non-courting male and compared these conditions to female silk deposition in the absence of male silk. We measured the quantity of three different types of silk (draglines, cord silk, and attachment disks) deposited by females across substrates previously occupied by a courting male, a non-courting male, or no male. Females significantly increased attachment disk deposition in the presence of silk from a courting rather than a non-courting male. Females also showed elevated dragline deposition in the presence o...