Tarantula urticating setae are modified setae located on the abdomen or pedipalps, which represent an effective defensive mechanism against vertebrate or invertebrate predators and intruders. They are also useful taxonomic tools as morphological characters facilitating the classification of New World theraphosid spiders. In the present study, the morphology of urticating setae was studied on 144 taxa of New World theraphosids, including ontogenetic stages in chosen species, except for species with urticating setae of type VII. The typology of urticating setae was revised, and types I, III and IV were redescribed. The urticating setae in spiders with type I setae, which were originally among type III or were considered setae of intermediate morphology between types I and III, are newly considered to be ontogenetic derivatives of type I and are described as subtypes. Setae of intermediate morphology between that of body setae and type II urticating setae that were found in Iridopelma hirsutum and Antillena rickwesti may provide another evidence that type II urticating setae evolved from body setae. It is supposed that the fusion of barbs with the shaft may lead to the morphology of type II setae. As the type II setae of Aviculariinae evolved independently to the UrS of Theraphosinae and both subfamilies represent two non-sister groups, this should explain the differences in the morphology of body setae in Aviculariinae and Theraphosinae. The terminology of "barbs" and "reversed barbs" was revised and redefined, newly emphasizing the real direction of barbs.
- MeSH
- Spiders anatomy & histology classification MeSH
- Sensilla anatomy & histology MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Instances of sexual size dimorphism (SSD) provide the context for rigorous tests of biological rules of size evolution, such as Cope's rule (phyletic size increase), Rensch's rule (allometric patterns of male and female size), as well as male and female body size optima. In certain spider groups, such as the golden orbweavers (Nephilidae), extreme female-biased SSD (eSSD, female:male body length $\ge$2) is the norm. Nephilid genera construct webs of exaggerated proportions, which can be aerial, arboricolous, or intermediate (hybrid). First, we established the backbone phylogeny of Nephilidae using 367 anchored hybrid enrichment markers, then combined these data with classical markers for a reference species-level phylogeny. Second, we used the phylogeny to test Cope and Rensch's rules, sex specific size optima, and the coevolution of web size, type, and features with female and male body size and their ratio, SSD. Male, but not female, size increases significantly over time, and refutes Cope's rule. Allometric analyses reject the converse, Rensch's rule. Male and female body sizes are uncorrelated. Female size evolution is random, but males evolve toward an optimum size (3.2-4.9 mm). Overall, female body size correlates positively with absolute web size. However, intermediate sized females build the largest webs (of the hybrid type), giant female Nephila and Trichonephila build smaller webs (of the aerial type), and the smallest females build the smallest webs (of the arboricolous type). We propose taxonomic changes based on the criteria of clade age, monophyly and exclusivity, classification information content, and diagnosability. Spider families, as currently defined, tend to be between 37 million years old and 98 million years old, and Nephilidae is estimated at 133 Ma (97-146), thus deserving family status. We, therefore, resurrect the family Nephilidae Simon 1894 that contains Clitaetra Simon 1889, the Cretaceous GeratonephilaPoinar and Buckley (2012), Herennia Thorell 1877, IndoetraKuntner 2006, new rank, Nephila Leach 1815, Nephilengys L. Koch 1872, Nephilingis Kuntner 2013, Palaeonephila Wunderlich 2004 from Tertiary Baltic amber, and TrichonephilaDahl 1911, new rank. We propose the new clade Orbipurae to contain Araneidae Clerck 1757, Phonognathidae Simon 1894, new rank, and Nephilidae. Nephilid female gigantism is a phylogenetically ancient phenotype (over 100 Ma), as is eSSD, though their magnitudes vary by lineage.
- MeSH
- Phylogeny * MeSH
- Spiders anatomy & histology classification genetics MeSH
- Sex Characteristics * MeSH
- Body Size genetics MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
Specialized predators possess a variety of adaptations. In venomous predators, this may include the size of the venom gland and venom composition. It is expected that due to different foraging strategies, predators with a wide trophic niche (generalists) should possess larger venom glands that contain more diversified components than predators with a narrow niche (specialists). We focused on spiders, as the most diversified group of venomous predators, in which a wide variety of trophic strategies have evolved. We conducted a comparative analysis using 40 spider species, in which we measured the size of their venom gland and venom complexity using proteome profiling methods. The species were classified into three trophic groups: generalists, facultative specialists and obligatory specialists. We found that the venom glands of generalists are larger than those of obligatory specialists, which is presumably due to more frequent prey capture by the former. The complexity of venom of peptides (2-15 kDa) and proteins (15-250 kDa) was more diverse in generalists than in specialists. Multivariate analysis of venom revealed significant differences among the three trophic categories only in the complexity of peptides. Our study thus shows that venom gland size and its content have taken different pathways during the evolution of different trophic strategies in spiders. Generalists evolved larger venom glands with more complex composition, whereas obligatory specialists possess smaller glands with less diverse chemical structures.
- MeSH
- Biological Evolution * MeSH
- Phylogeny MeSH
- Spider Venoms chemistry MeSH
- Spiders anatomy & histology classification MeSH
- Proteome chemistry MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Spiders produce multiple silks with different physical properties that allow them to occupy a diverse range of ecological niches, including the underwater environment. Despite this functional diversity, past molecular analyses show a high degree of amino acid sequence similarity between C-terminal regions of silk genes that appear to be independent of the physical properties of the resulting silks; instead, this domain is crucial to the formation of silk fibers. Here, we present an analysis of the C-terminal domain of all known types of spider silk and include silk sequences from the spider Argyroneta aquatica, which spins the majority of its silk underwater. Our work indicates that spiders have retained a highly conserved mechanism of silk assembly, despite the extraordinary diversification of species, silk types and applications of silk over 350 million years. Sequence analysis of the silk C-terminal domain across the entire gene family shows the conservation of two uncommon amino acids that are implicated in the formation of a salt bridge, a functional bond essential to protein assembly. This conservation extends to the novel sequences isolated from A. aquatica. This finding is relevant to research regarding the artificial synthesis of spider silk, suggesting that synthesis of all silk types will be possible using a single process.
- MeSH
- Phylogeny MeSH
- Silk chemistry genetics MeSH
- Hydrogen-Ion Concentration * MeSH
- Protein Conformation * MeSH
- Conserved Sequence MeSH
- Evolution, Molecular MeSH
- Models, Molecular * MeSH
- Multigene Family MeSH
- Spiders classification genetics MeSH
- Protein Domains * genetics MeSH
- Amino Acid Sequence MeSH
- Gene Expression Profiling MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Cobweb spiders (Theridiidae) are highly diverse from the perspective of species richness, morphological diversity, variety of web architecture, and behavioral repertoires. The family includes over 50% of social spiders, a behavioral rarity among the order, and members of the family are furthermore the subject of research on venom, silk biomechanics, kleptoparasitism and web building, among other traits. Theridiidae is one of the most abundant groups of spiders, and thus key insect predators in many different ecosystems and is among relatively few spider families that show high degree of myrmecophagy. Modern comparative studies on all these fronts are best buttressed on a phylogenetic foundation. Our goal here is to offer a revised, dated, phylogenetic hypothesis for the family by summarizing previously published data from multiple molecular and morphological studies through data-mining, and adding novel data from several genera. We also test the hypothesis that the origin and diversification of cobweb spiders coincides with that of ants on which many species specialize as prey. The new phylogeny is largely congruent with prior studies and current taxonomy and should provide a useful tool for theridiid classification and for comparative analyses. Nevertheless, we also highlight the limitations of currently available data-the state of the art in Theridiidae phylogenetics-offering weak support for most of the deeper nodes in the phylogeny. Thus the need is clear for modern phylogenomic approaches to obtain a more solid understanding, especially of relationships among subfamilies. We recover the monophyly of currently recognized theridiid subfamilies with the exception of some enigmatic 'pholcommatines' (Styposis, Phoroncidia) and putative 'hadrotarsines' (Audifia, Tekellina) whose placement is uncertain in our analyses. Theridiidae dates back some 100 mya to the Cretaceous, a period of diversification in flowering plants and many groups of insects, including ants. The origin of cobweb spiders, and hence the cobweb-a speciallized trap for pedestrian prey-coincides with a major diversification shift in ants. The family becomes abundant in fossil record 50-40 mya as ants also diversify and reach dominance and contemporary patterns of abundances of theridiids and ants show the same trends, with increasing relative abundance towards the equator and at lower altitudes. We find that among orbiculariae, lineages that specialize on ant prey are non-randomly clustered within Theridiidae. Given these findings we hypothesize that the origin of the gumfoot web was a stepping stone that facilitated the capture of ants and resulted in specialized myrmecophagy in a number of 'basal' theridiids. We also document a subsequent loss in myrmecophagy, and associated increase in speciation rates, as 'recent' theridiid groups evolve diverse web forms and many return to the capture of aerial prey.
- MeSH
- Bayes Theorem MeSH
- Biological Evolution MeSH
- Ants genetics MeSH
- Phylogeny * MeSH
- Genetic Variation genetics MeSH
- DNA, Mitochondrial genetics MeSH
- Spiders classification genetics MeSH
- RNA, Ribosomal genetics MeSH
- Sequence Analysis, DNA MeSH
- Fossils MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
During faunistic research of reed beds associated with lakes in the Pannonian region of Czechia we found an Enoplognatha species with spectacular morphology of the male chelicerae. Despite this species being found in an arachnologically well researched area, and that the European species of the genus Enoplognatha have been recently revised (Bosmans & Van Keer 1999), it appears to be a new species.
- MeSH
- Species Specificity MeSH
- Mitochondria genetics MeSH
- Wetlands MeSH
- Spiders anatomy & histology classification genetics MeSH
- Sequence Analysis, DNA MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Letter MeSH
- Geographicals
- Czech Republic MeSH
- MeSH
- Histamine Antagonists therapeutic use MeSH
- Disinfectants MeSH
- Diagnosis, Differential MeSH
- Adrenal Cortex Hormones therapeutic use MeSH
- Spider Bites * diagnosis epidemiology drug therapy mortality MeSH
- Humans MeSH
- Spider Venoms pharmacokinetics pharmacology adverse effects MeSH
- Spiders classification MeSH
- Drug Administration Routes MeSH
- Check Tag
- Humans MeSH
Phage WO is a bacteriophage found in Wolbachia. Herein, we represent the first phylogenetic study of WOs that infect spiders (Araneae). Seven species of spiders (Araneus alternidens, Nephila clavata, Hylyphantes graminicola, Prosoponoides sinensis, Pholcus crypticolens, Coleosoma octomaculatum, and Nurscia albofasciata) from six families were infected by Wolbachia and WO, followed by comprehensive sequence analysis. Interestingly, WO could be only detected Wolbachia-infected spiders. The relative infection rates of those seven species of spiders were 75, 100, 88.9, 100, 62.5, 72.7, and 100 %, respectively. Our results indicated that both Wolbachia and WO were found in three different body parts of N. clavata, and WO could be passed to the next generation of H. graminicola by vertical transmission. There were three different sequences for WO infected in A. alternidens and two different WO sequences from C. octomaculatum. Only one sequence of WO was found for the other five species of spiders. The discovered sequence of WO ranged from 239 to 311 bp. Phylogenetic tree was generated using maximum likelihood (ML) based on the orf7 gene sequences. According to the phylogenetic tree, WOs in N. clavata and H. graminicola were clustered in the same group. WOs from A. alternidens (WAlt1) and C. octomaculatum (WOct2) were closely related to another clade, whereas WO in P. sinensis was classified as a sole cluster.
BACKGROUND: Sperm competition imposes a strong selective pressure on males, leading to the evolution of various physiological, morphological and behavioral traits. Sperm competition can be prevented by blocking or impeding the access to female genitalia by means of a mating plug. We investigated the factors responsible for plug production and function in the promiscuous female-cannibalistic spider Micaria sociabilis (Gnaphosidae). RESULTS: We performed mating trials using females with and without a plug that consists of an amorphous mass. The mating trials demonstrated that the probability of male plugging increased non-linearly with the duration of copulation. Copulation duration and plug production seem to be controlled by the female. We found that females terminated matings later if males were fast at genital coupling. Whereas incomplete plugs had disappeared on the day following copulation, complete plugs persisted (40%). In matings with females with complete plugs, only a small proportion of males (7%) were able to remove the plug, indicating the high effectiveness of plugging. Moreover, males ceased attempts to copulate with plugged females with higher probability. 3D X-ray microscopy of the female and male genitalia showed that the plug material can extend far into the female genital tract and that the plug material is produced by a massive gland inside the palpal organ of the modified male pedipalps. CONCLUSIONS: Our study demonstrates that the mating plug in M. sociabilis constitutes an effective male strategy to avoid sperm competition that seems to be under female control.
- MeSH
- Behavior, Animal MeSH
- Competitive Behavior MeSH
- Copulation MeSH
- Spiders classification physiology MeSH
- Genitalia, Female MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- MeSH
- Food Contamination prevention & control MeSH
- Spider Bites diagnosis prevention & control psychology MeSH
- Humans MeSH
- Commerce MeSH
- Spider Venoms adverse effects MeSH
- Spiders * anatomy & histology classification growth & development MeSH
- Information Dissemination MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Geographicals
- Czech Republic MeSH
