Search

Here we study the evolution of nucleotide composition in third codon-positions of CO1 sequences of Chelicerata, using a phylogenetic framework, based on 180 taxa and three markers (CO1, 18S, and 28S rRNA; 5,218 nt). The analyses of nucleotide composition were also extended to all CO1 sequences of Chelicerata found in GenBank (1,701 taxa). The results show that most species of Chelicerata have a positive strand bias in CO1, i.e., in favor of C nucleotides, including all Amblypygi, Palpigradi, Ricinulei, Solifugae, Uropygi, and Xiphosura. However, several taxa show a negative strand bias, i.e., in favor of G nucleotides: all Scorpiones, Opisthothelae spiders and several taxa within Acari, Opiliones, Pseudoscorpiones, and Pycnogonida. Several reversals of strand-specific bias can be attributed to either a rearrangement of the control region or an inversion of a fragment containing the CO1 gene. Key taxa for which sequencing of complete mitochondrial genomes will be necessary to determine the origin and nature of mtDNA rearrangements involved in the reversals are identified. Acari, Opiliones, Pseudoscorpiones, and Pycnogonida were found to show a strong variability in nucleotide composition. In addition, both mitochondrial and nuclear genomes have been affected by higher substitution rates in Acari and Pseudoscorpiones. The results therefore indicate that these two orders are more liable to fix mutations of all types, including base substitutions, indels, and genomic rearrangements. [ABSTRACT FROM AUTHOR]

The article discusses a new pseudoscorpion species, Dactylochelifer luyaensis, which belongs to the family Cheliferidae Risso found in the Shanxi Province of China. It informs that the carapace of the new found species is strongly and evenly granular and is of dark brown color. It further reports that its abdomen is weakly granular and lateral keels are absent. It also talks about venom apparatus being present in both the chelal fingers.

A new species of Synsphyronus, S. christopherdarwini, is described from Charles Darwin Reserve, Western Australia. The species occurs on several granite outcrops where they congregate under exfoliating pieces of granite. [ABSTRACT FROM AUTHOR]

The pseudoscorpion genus Allochthonius Chamberlin, 1929, belonging to the family Pseudotyrannochthoniidae Beier, 1932, is reported from China, and the subgeneric characters of Allochthonius (Allochthonius) are reviewed in detail. Three new species are diagnosed, described and illustrated under the names Allochthonius (A.) fuscus sp. nov., A. (A.) wui sp. nov. and A. (A.) trigonus sp. nov. A distribution map and a key to the species of subgenus Allochthonius (A.) are provided. In addition, Centrochthonius sichuanensis Schawaller, 1995 is transferred to Allochthonius, forming the new combination A. (A.) sichuanensis (Schawaller). [ABSTRACT FROM AUTHOR]

Records of mites parasitizing pseudoscorpions are summarized and new host-parasite associations are reported. Trombidium brevirnanum (Berlese 1910) (Trombidiidae) has been found on Neobisium bernardi bernardi Vachon 1937 in France (new country record for T. brevimanum), and T. mediterraneum on N. carcinoides (Hermann 1804) in Norway (new country record for T. mediterraneum). These are the first cases in which both the mite and the pseudoscorpion have been identified. An additional record of Trombidium sp. (probably T. mediterraneum) on Neobisium fuscimanum (C.L. Koch 1843) is given from Poland. A previously unpublished record of a Leptus larva on a pseudoscorpion, possibly belonging to the genus Neobisium, is noted from France. Parasitism of Roncus lubricus L. Koch 1873 by an unidentified larva of Parasitengona (probably Trombidiidae) is also noted from Germany. The stylostomes (feeding canals) formed in pseudoscorpions by trombidiid mites are similar to those produced in other hosts. Scars in the pleurum of the pseudoscorpions are interpreted as the result of attempts at fixation by the mite larvae. Pseudoscorpions appear to represent alternative hosts for Trombidium larvae, although the successful completion of development has yet to be demonstrated. [ABSTRACT FROM AUTHOR]

We modelled presence/absence per tree of beetles and pseudoscorpions living in tree hollows in relation to trunk circumference, habitat openness, and connectivity (= density of hollow oaks in the surrounding area), using data from 281 oaks. The presence/absence models were then used to predict species' occurrences in a county (11,600 km) in southeastern Sweden. For eight of the nine species, the most parsimonious occupancy model included a positive relationship with connectivity and at least one tree characteristic. Occupancy underestimates from occurrence records-the ratio of the area of occupancy based on our predictive model to the area of occupancy based on occurrence records-varied between 3 and 83 among species when using occurrence records up to 1993, with significantly larger underestimates for smaller beetle species. Today (after extensive surveys), underestimation has decreased to 1.3-25, confirming that calculations solely based on species occurrence records greatly underestimate the area of occupancy. We suggest this should be taken into account to a greater extent and in a clearer way than today when constructing red lists. The radius of the connectivity measure that generated the best fit varied between 135 and 2,857 m among species, with longer distances for more threatened species. Consequently, preservation of the most threatened species ( Elater ferrugineus and Tenebrio opacus) requires conservation efforts at larger spatial scales than required to protect Osmoderma eremita, which frequently has been used as an indicator and umbrella species. [ABSTRACT FROM AUTHOR]

Division of labor is a strategy that maximizes the foraging and reproductive success of eusocial insects. Although some arachnids exhibit colony structure and social organization similar to that of hymenopterans, temporal polyethism has only been demonstrated in few species. The social organization of cooperative pseudoscorpions Paratemnoides nidificator is similar to that of social spiders, but it involves a clear division of labor. Work allocation was experimentally investigated in colonies composed of only one developmental stage (young or adults) or by one sex (males or females), through laboratory manipulation. During 44 h of observation, more than 14 000 behavioral repetitions were quantified, distributed in 95 different types of behavioral acts, and grouped in 10 behavioral categories. The results showed that reproductive colonies of P. nidificator are maintained by gender- and age-based activities. Males and non-reproductive females performed the external cleaning of the colony and prey capture. Reproductive females take care of the juveniles and build reproductive silk chambers. Nymphs build most of the molt chambers and perform internal cleaning. In the absence of nymphs, male colonies survived 1-2 mo, while female colonies survived 3-4 mo. In nymph colonies, work is readjusted so that all maintenance tasks are executed. This is the first study clearly demonstrating division of tasks in arachnids. It suggests that specialization is an adaptative and evolutionarily old trait in this species. Unlike cooperative spiders, P. nidificator possesses physiological (e.g. reproduction, ecdysis, lifespan) and behavioral (e.g. behavioral synchrony or self-organization) characteristics that allow task specialization. [ABSTRACT FROM AUTHOR]

A large number of new localities for Aphelolpium scitulum, A. brachytarsus, A. thibaudi, P. arubense arubense, P. a. variabile, P. confusum and P. granulatum are reported. Two new identification keys are given: an adapted and extended key to the Caribbean genera of the pseudoscorpion family Olpiidae and a revised key to the species of the genus Pachyolpium Beier from the West Indies. [ABSTRACT FROM AUTHOR]

The article discusses the conservation of the pseudoscorpion generic name Neobisium Chamberlin as a precedence over the term Blothrus Shiödte. Blothrus is a term being applied as a synonym or subgenus of Neobisium. The term Blothrus was proposed by Danish entomologist Jørgen Matthias Christian Schiödte to be applied to a large cave-dwelling pseudoscorpion from Slovenia. Neobisium refers to a group of pseudoscorpions that may be found in the Palaeartctic region. Such term was proposed by researcher J.C. Chamberlin for a group of species forming part of Obisium.

This study aimed at comparing six patch connectivity measures by fitting them to field data. We used occupancy data for eight beetle and two pseudoscorpion species from 281 hollow oaks in southeast Sweden. Species occupancy was modelled in relation to tree characteristics and one measure of patch connectivity at a time. For each connectivity measure we searched for the spatial scale that generated the best fit to field data. Connectivity measures that only include occupied patches provided better model fits than those that include all patches. When occupancy data are absent for surrounding habitat patches, information that reflects occurrence probabilities can be included in the connectivity measure. However, in this study incorporation of such information resulted in only a slight improvement of model fit. A frequently used connectivity measure based on the negative exponential function was relatively poor in explaining species' occurrence; for eight species out of nine a buffer measure was better. A better fit was obtained when the negative exponential function was modified to take into account that habitat patches may 'compete' for the immigrants. The spatial scale with the best fit tended to be larger when we used connectivity measures in which dispersal sources are identified with lower precision. Thus, the outcomes from different multiple-scale studies are not directly comparable if the density of dispersal sources is not measured in the same way. Overall we conclude that buffer measures are useful, as they give good predictions and are easy to understand and use. If a biologically more realistic measure is needed, one that up-weights the closest patches should be used. Finally, the possibility that habitat patches may compete with each other for immigrants should be considered when selecting a connectivity measure. [ABSTRACT FROM AUTHOR]

Two new species of Synsphyronus, S. francesae and S. ellenae, are described from southern Western Australia. These species occur on granite outcrops where they congregate under exfoliating pieces of granite. Synsphyronus francesae occurs near the south coast of Western Australia, while S. ellenae occurs in the central wheatbelt region. Synsphyronus ellenae is the fi rst species of the genus with an adult trichobothrial pattern of six trichobothria on the fi xed fi nger and two on the moveable fi nger (6/2), although some variation was observed with fi ve or seven trichobothria occasionally present. All other species of Synsphyronus have patterns of 8/3, 8/2, 8/1, 7/2 or 7/1. The only other species of Garypidae with a 6/2 pattern is Meiogarypus mirus Beier from Namibia, and the only species with lower trichobothrial numbers are Elattogarypus cruciatus Beier from South Africa, E. somalicus Mahnert from Somalia, E. cicatrosus Mahnert from the Yemeni island of Socotra, and Eremogarypus eximius Beier from Namibia, each with a 5/1 pattern. The conservation status of these species is examined. [ABSTRACT FROM AUTHOR]

List of endangered pseucoscorpion species of Germany (Red Data Book) (Arachnida: Pseudoscorpiones)

Amblyolpium goldastehae spec. nov., is described and illustrated on the basis of two males collected from western Iran. Its ability to live in a dry and xerotherme habitat is also discussed. [ABSTRACT FROM AUTHOR]

The karyotypes and course of meiosis of two pseudoscorpions, Semeiochernes armiger (Balzan 1892) and Cordylochernes scorpioides (Linnaeus 1758) (Pseudoscorpiones: Chernetidae), are described for the first time. The diploid chromosome number of the male is 69 in S. armiger and 47 in C. scorpioides. As in most pseudoscorpions studied to date, autosomes exhibit predominantly biarmed morphology. Both species possess an XO sex chromosome system. In most pseudoscorpions with XO system karyotyped so far, including European chernetids, the X chromosome exhibits metacentric morphology. In contrast, the X chromosome of both neotropical chernetids studied exhibits asymmetric, submetacentric morphology. [ABSTRACT FROM AUTHOR]

Wolbachia are maternally inherited, cellular endosymbionts that can enhance their fitness by biasing host sex ratio in favour of females. Male killing (MK) is an extreme form of sex-ratio manipulation that is selectively advantageous if the self-sacrifice of Wolbachia in males increases transmission through females. In live-bearing hosts, females typically produce more embryos than can be carried to term, and reproductive compensation through maternal resource reallocation from dead males to female embryos could increase the number of daughters born to infected females. Here, we report a new strain of MKWolbachia (wCsc2) in the pseudoscorpion, Cordylochernes scorpioides, and present the first empirical evidence that reproductive compensation favours the killing of males in a viviparous host. Females infected with the wCsc2 strain produced 26 per cent more and significantly larger daughters than tetracycline-cured females. In contrast to the previously described wCsc1 MK Wolbachia strain in C. scorpioides, wCsc2 infection was not accompanied by an increase in the rate of spontaneous brood abortion. Characterization of the wCsc1 and wCsc2 strains by multi-locus sequence typing and by Wolbachia surface protein (wsp) gene sequencing indicates that the marked divergence between these two MK strains in their impact on host reproductive success, and hence in their potential to spread, has occurred in association with homologous recombination in the wsp gene. [ABSTRACT FROM AUTHOR]

We sampled 505 specimens of 7 arachnid orders (313 Araneae, 65 Opiliones, 111 Pseudoscorpiones, 10 Ricinulei, 3 Schizomida, 1 Thelyphonida, 2 Scorpiones) in natural forest and agroforestry sites in central Amazonia analyze fresh and dry mass to body length relations. The low number of schizomids, scorpions, and thelyphonids did not allow statistical analyses, but the raw data are given, because these represent the first data published for these groups from Amazonia. For all other orders general mass-length relationships for ecological studies were determined. Non-linear regressions with a power model proved to describe the relations very well and are highly significant for all taxa and groups analyzed. The resulting equations can thus be used to estimate biomass of large samples of arachnids from Amazonia based on individual body length measurements. Linear regressions of mass to length with log-transformed data also described the relation adequately, but using the resulting equations to estimate biomass of the whole spider sample caused a higher bias. This is because small biases of mass-length relation of the largest spider individuals are exponentiated, However, linear regressions behaved better for spiders smaller than 8 mm. The ratio of dry to fresh mass was around 0.3 for spiders; 0.4 for pseudoscorpions, schizomids, and thelyphonids; 0.44 for opilionids; and 0.53 for Ricinulei. A second sample of 99 spiders from a South Brazilian Atlantic Forest revealed similar mass-length relations, but a different dry to fresh mass ratio. For spiders, the usefulness of general equations to determine the biomass of bulk samples from ecological studies with certain precision requirements was further explored by using the equations from the two datasets crosswise, regarding the resulting bias and by applying equations to a further dataset from an ecological investigation. In conclusion and accordance to former studies, general equations derived from mass-length regressions of bulk samples including many specimens different families and guilds are appropriate for an estimation of the biomass of bulk samples from ecological studies. Equations from mass-length regressions from the literature, resulting from spider samples in temperate regions, should not be used to estimate biomass of samples from neotropical spider assemblages, especially when absolute biomass is of interest and when precision is required. They underestimate biomass of tropical assemblages due to a strong bias in mass-length relation of tropical spiders larger than 10 mm. Depending on the distribution of large spiders in samples, considerable biases in single samples could affect ecological analyses. [ABSTRACT FROM AUTHOR]

Abstract: Sequence data from a segment of the mitochondrial cytochrome c oxidase subunit I (COI) gene were used to examine phylogenetic relationships, estimate gene flow and infer demographic history of the cactophilic chernetid pseudoscorpion, Dinocheirus arizonensis (Banks), from the Sonoran Desert. Phylogenetic trees resolved two clades of D. arizonensis, one from mainland Sonora, Mexico and southern Arizona (clade I) and the other from the Baja California peninsula and southern Arizona (clade II). The two clades were separated by a mean genetic distance (d) of ∼2.6%. Hierarchical analysis of molecular variance indicated highly significant population structuring in D. arizonensis (overall Φ ST =0.860; P <0.0001), with 80% of the genetic variation distributed among the two clades. Most pairwise comparisons of Φ ST among populations within each clade, however, were not significant. The results suggest that phoretic dispersal on vagile cactophilic insects such as the neriid cactus fly Odontoloxozus longicornis (Coquillett) provides sufficient gene flow to offset the accumulation of unique haplotypes within each clade of the non-vagile pseudoscorpion. Preliminary results on dispersal capability of O. longicornis were consistent with this conclusion. Tests designed to reconstruct demographic history from sequence data indicated that both clades of D. arizonensis, as well as O. longicornis, have experienced historical population expansions. Potential barriers to gene flow that may have led to genetic isolation and diversification in clades I and II of D. arizonensis are discussed. [Copyright &y& Elsevier]

The resurrected genus Cyphophthalmus is defined morphoanatomically and its relationship with the genus Siro, from which it has been separated, is discussed. The genus Tranteeva is synonymized with Cyphophthalmus. Twelve new species are here described: Cyphophthalmus paragamiani, Cyphophthalmus thracicus, Cyphophthalmus gordani, Cyphophthalmus neretvanus, Cyphophthalmus kratochvili, Cyphophthalmus conocephalus, Cyphophthalmus trebinjanus, Cyphophthalmus ognjenovici, Cyphophthalmus martensi, Cyphophthalmus rumijae, Cyphophthalmus zetae, Cyphophthalmus hlavaci, two re-described: Cyphophthalmus minutus and Cyphophthalmus corfuanus, and for C. corfuanus, Cyphophthalmus bithynicus, and Cyphophthalmus yalovensis a new status is given. Relevant taxonomic characters are reviewed to illustrate the diversity of Balkan sironids. Phyletic relationships amongst species are reviewed and discussed. The results provide the basis for discussion on the relevance of minute morphological differences in the taxonomy of Cyphophthalmi. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 156, 260–318. [ABSTRACT FROM AUTHOR]

Despite the great biodiversity in the Arachnida, some taxa are still now poorly known, mainly in terms of biology, ecology, and behavior. Pseudoscorpions are small arachnids (2–8 mm) that live in cryptic environments, being in general solitary predators of other invertebrates. The most studied Pseudoscorpion species are those from temperate areas, which revealed that Pseudoscorpiones present some level of sociality based on maternal care. Most developed sociality is seen in tropical species. Here, we reviewed this issue, presented examples of social behavior, and suggested the steps involved in the evolution of permanent sociality in the Neotropical Atemnidae genus, Paratemnoides. We discussed that the extended parental care, division of labor, cooperative breeding and feeding, and the tolerance among members dividing the same share could be considered enough to characterize a true social life, same in invertebrates. [ABSTRACT FROM AUTHOR]

Abstract: The phylogenetic relationships of the major lineages of the arachnid order Pseudoscorpiones are investigated for the first time using molecular sequence data from two nuclear ribosomal genes and one mitochondrial protein-encoding gene. The data were analyzed using a dynamic homology approach with the new program POY v.4 under parsimony as the optimality criterion. The data show monophyly of Pseudoscorpiones as well as many of its superfamilies (Feaelloidea, Chthonioidea, Cheiridioidea and Sternophoroidea), but not for Neobisiodea or Garypoidea. Cheliferoidea was not monophyletic either due to the position of Neochelanops, which grouped with some garypoids. In all the analyses, Feaelloidea constituted the sister group to all other pseudoscorpions; Chthonioidea is the sister group to the remaining families, which constitute the group Iocheirata sensu Harvey—a clade including pseudoscorpions with venom glands within the pedipalpal fingers. This phylogenetic pattern suggests that venom glands evolved just once within this order of arachnids. [Copyright &y& Elsevier]

The morphological features of the developmental stages of Neobisium erythrodactylum (Koch, 1873), a new record for the Turkish fauna, are given. [ABSTRACT FROM AUTHOR]

Determining whether reproductive isolation evolves through mate choice and/or gametic factors that prevent fertilization or through the post-zygotic mechanisms of hybrid sterility or inviability is fundamental to understanding speciation. Investigation of the pre- and post-zygotic components of reproductive isolation is facilitated in the pseudoscorpion, Cordylochernes scorpioides, by its indirect method of sperm transfer and viviparous embryonic development. Previous research on this species, in which mate discrimination was assessed in virgin females, suggested that female choice played only a minor role in reproductive isolation between populations from French Guiana and Panamá. Here, in a study of three allopatric populations of C. scorpioides from Panamá, we assessed mating-stage isolation in both virgin and once-mated females, and found that female discrimination depends critically on mating status. Virgin females were almost invariably receptive, showing no tendency to discriminate against males from allopatric populations. By contrast, non-virgin females were significantly more likely to reject foreign males than males from their own population. Male sexual motivation could not account for differences in either female sexual receptivity or male success in sperm transfer. Allopatric and sympatric males did not differ in number of spermatophores deposited as either a female’s first or second mate. Nonetheless, allopatric males achieved significantly lower sperm transfer success not only with choosy, non-virgin females but also with virgin females. Given the lack of behavioral discrimination by virgin females, female receptivity was not the only factor influencing differences in sperm transfer success. Multivariate analysis of spermatophore morphology suggests that the higher failure rate of matings between allopatric males and virgin females resulted from population differences in sperm packet architecture. Overall, our findings indicate that assessment of discrimination against allopatric males that is limited to virgin females may seriously underestimate the contribution of female mate choice to reproductive isolation between populations. [ABSTRACT FROM AUTHOR]

Dasychernes inquilinus Chamberlin 1929. the type species of the genus, was described from specimens taken from colonies of the stingless honey bee Melipona salti Schwarz 1932 (Hymenoptera, Apidae). For the first time since its description, we report D. inquilinus from a nest of M. compressipes (Fabricius 1804) and, to document intraspecific variation, we also provide descriptive notes on the female pedipalp and leg. We discuss the rareness of D. inquilinus and summarize published information on pseudoscorpion-bee relationships. We found a total of 15 pseudoscorpion species (six genera in three families) reported from colonies of three stingless bee species and two honey bee species. The role of pseudoscorpions within bee nests is still poorly known. Like our notes on D. inquilinus, most records of pseudoscorpion-bee relationships are sporadic observations, sparsely reported in the literature. [ABSTRACT FROM AUTHOR]

The neobisioid pseudoscorpion family Hyidae has a distribution spanning the margins of the Indian Ocean and its phylogenetic position has been suggested to lie midway between a clade containing the Bochidae and Ideoroncidae, and a clade containing the remaining neobisioid families, Gymnobisiidae, Neobisiidae, Parahyidae and Syarinidae. Their central position within the Neobisioidea, and their biogeographic patterns, have prompted the present study, which is designed to test the monophyly of the family, deduce the phylogeny of all known hyids and to describe several newly discovered species. The phylogenetic analysis of the 14 species of the pseudoscorpion family Hyidae along with 20 other species of Neobisioidea demonstrates the monophyly of the family and its distinctness from all other neobisioid families. Two genera, Hya Chamberlin and Indohya Beier, are recognised, even though the phylogenetic analysis did not consistently recover the monophyly of Indohya. The effect of outgroup selection was tested on the Hyidae and revealed markedly different tree topologies. Hyella Harvey, with the type species H. humphreysi Harvey, is newly synonymised with Indohya owing to similarities between the previously described species and some new troglobitic species. The Indohyinae Harvey is synonymised with Hyidae. Two new epigean species and three new troglobitic species of Indohya are described: I. damocles, sp. nov., I. gollum, sp. nov., I. haroldi, sp. nov. and I. napierensis, sp. nov. from northern Western Australia, and I. jacquelinae, sp. nov. from Madagascar. All species of Indohya are short-range endemics, having very small distributional ranges. New data are presented for Indohya humphreysi (Harvey), including the first description of the male. The first protonymphs of the family Hyidae are described, including those of Hya minuta (Tullgren) and Indohya gollum, sp. nov. [ABSTRACT FROM AUTHOR]

Aim To investigate molecular phylogenetic divergence and historical biogeography of the cave-dwelling pseudoscorpion genus Protochelifer. Location Caves and nearby epigean habitats in southern Australia were sampled from western Victoria, Naracoorte Caves, Flinders Ranges, Kangaroo Island, Nullarbor Plain and south-west Western Australia. Methods Allozyme electrophoresis (57 individuals) and a 569-base-pair section of the mtDNA COI gene (22 individuals) were used to reconstruct phylogenetic relationships among four cave species and three epigean species from 13 locations. Results Phylogenetic reconstruction using the allozyme and mtDNA sequence data revealed a similar topology, showing recent speciation of several Protochelifer populations in caves from Naracoorte to the Nullarbor Plain. Naracoorte Caves contained a single species, Protochelifer naracoortensis, found in four separate caves, while all other cave species appear to be restricted to single caves. Main conclusions At a local scale, as indicated by the four Naracoorte caves, dispersal is thought to occur via micro- and mesocaverns, and possibly by phoresy using insect or bat vectors. With current data we are unable to determine if cavernicolous species of Protochelifer have arisen from a single cave colonization event followed by phoretic dispersal on bats to other caves, or multiple cave-invasion events from independent epigean ancestors. Genetic heterogeneity among Protochelifer populations from Nullarbor caves suggest that P. cavernarum, the only species presently recorded from this region, is likely to constitute a species complex requiring further study to fully resolve its relationships. [ABSTRACT FROM AUTHOR]

1. In the size–grain hypothesis (a) long legs allow walking organisms to step over gaps and pores in substrate but prohibit them from entering those gaps; (b) the world is more rugose for small organisms; and (c) the relative cost of long legs increases as organisms grow smaller. The hypothesis predicts a positive allometry of leg length ( = mass b where b > 0.33 of isometry), a pattern that robustly holds for ants. 2. Toward testing for leg length allometries in other taxa, arthropods were extracted from the Panama leaf litter and measured. Three common taxa (spiders, diplopods, Coleoptera) yielded bs that exceeded 0.33 while three others (Acarina, Pseudoscorpiones, and Collembola) did not. The exponent b tended to increase ( P = 0.06, n= 7) with an arthropod taxon’s average body mass. 3. Since leg length in cursorial organisms tends toward isometry in very small and very large taxa (i.e. mammals) this suggests that the size–grain hypothesis may best apply at a transition zone of intermediate body mass: the macroarthropods. 4. Body length was a robust predictor of mass in all groups despite variation in shape. [ABSTRACT FROM AUTHOR]

The article presents the list of pseudoscorpions species or arachnids from Colombia. According to the authors, the known species in the country were recorded by foreign authors since 1800s, however, detailed information about each species were not recorded. In connection, researchers D. E. Florez and H. Sànchez published a preliminary list that established nine species distributed in nine genera and six families.

The morphological features of the developmental stages of Pselaphochernes scorpioides Hermann, 1804 are given. [ABSTRACT FROM AUTHOR]

The winter activity of spiders and pseudoscorpions, recorded during ten years (1994–2003) in the Dolomites and the Venetian Pre-Alps, is reported. The family Linyphiidae s.l. showed the highest number of active species, 69% of the total, and 88% of all the collected specimens. The spider Lepthyphantes cristatus was the most abundant species, including 42% of the individuals. Data on the families' abundance and phenology are compared with previous observations from Canada and Northern Europe. [ABSTRACT FROM AUTHOR]

This study, based on an analysis of some palaeo-Mediterranean pseudoscorpions (Ernstmayria venizelosi n. sp. and E. apostolostrichasi Curcic and Dimitrijevic from the family Neobisiidae) represents an outstanding improvement of our knowledge of the diversity of relict and distributionally limited false scorpions from the ancient (or proto-) Aegean area. Both E. venizelosi n. sp. and E. apostolostrichasi originated in the proto-Balkan region; their ancestors are to be sought among extinct forms. Since Ernstmayria species presently inhabit the 'peripheral' location of the ancient Aegeis, it is evident that their remote ancestor gave rise to a number of recent genera which presently constitute two generic groups inhabiting the Mediterranean region: Neobisium Chamberlin, Occitanobisium Heurtault, Roncobisium Vachon, Protoneobisium Curcic, and Pennobisium Curcic, on the one hand, and Acanthocreagris Mahnert, Balkanoroncus Curcic, Insulocreagris Curcic, and Roncocreagris Mahnert, on the other. [ABSTRACT FROM AUTHOR]

Five new pseudoscorpion species belonging to the genus Ideoblothrus are named and described from Western Australia and the Northern Territory: I. pisolitus from a single pisolitic mesa near Pannawonica, I. nesotymbus from limestone karst on Barrow Island, I. westi from limestone karst near the Fortescue River, I. descartes from a vine thicket on Descartes Island in the Kimberley, and I. milikapiti from rainforest on Melville Island. New specimens of I. papillon Harvey from Papillon Cave and I. woodi Harvey from Cave C-167, Western Australia are recorded. A further species is recognised but not named as adult specimens are not available: Ideoblothrus sp. 'Mesa A' occurs within a different pisolitic mesa than I. pisolitus. [ABSTRACT FROM AUTHOR]

The morphological features of species, and adult and developmental stages of Lamprochernes savignyi (Simon, 1881), newly recorded for the Turkish Pseudoscorpion fauna, are given. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Maternally inherited, cellular endosymbionts can enhance their fitness by biasing host sex ratio in favor of females. Male killing (MK), an extreme form of sex-ratio manipulation, is selectively advantageous, if the death of males results in increased microbe transmission through female siblings. In live-bearing hosts, females typically produce more embryos than are brought to term, and reproductive compensation through maternal resource reallocation from dead male embryos to female siblings provides a direct, physiological mechanism that could increase the number of daughters born to infected females, thereby promoting MK endosymbiont spread. In this study, a Wolbachia-infected line and an uninfected line of the viviparous pseudoscorpion, Cordylochernes scorpioides were genetically homogenized for nuclear DNA by repeated backcrossing of the infected line with the uninfected, laboratory population. Photomicroscopy of early-stage embryos demonstrated that female C. scorpioides invariably produced an excess of embryos, with Wolbachia-infected females producing as many early-stage embryos as uninfected female controls. However, Wolbachia-infected females that successfully carried broods to term gave birth to significantly fewer offspring, indicating that the extreme female bias characteristic of their broods results from the killing rather than the feminization of male embryos. Infected females that carried broods to term gave birth to significantly larger nymphs and did produce 10% more female offspring than uninfected females. However, the slight transmission advantage that the MK Wolbachia accrued from this reproductive compensation appears to be heavily outweighed by the high rate of spontaneous brood abortion suffered by infected females. [Copyright &y& Elsevier]

We recorded 153 specimens from eleven species of pseudoscorpions, collected in 32 nests of five species of packrat of the genus Neotoma on the Mexican Plateau. In the nests of N. albigula we found Tychochernes inflatus, Lustrochernes grossus, Serianus dolosus, and Juxtachelifer fructuosus; in the nests of N. goldmani was T. inflatus; in the nests of N. micropus were Pachychernes sp. and Chelifer cancroides; in the nests of N. mexicana were Paraliochthonius sp., Larca chamberlini, S. dolosus, Illinichernes distinctus, and T. inflatus; and in the nests of N. palatina there were Cheiridium insperatum and Dinocheirus sp. We consider to the species Tychochernes inflatus, Pachychernes sp., Larca chamberlini, Illinichernes distinctus and Cheiridium insperatum as permanent inhabitants of these microhabitats. The majority of specimens (41.2 %) were found in the nest proper. We collected all life stages, with adults (39.9 %) being the most abundant. A key for the identification of the pseudoscorpions found is given. [ABSTRACT FROM AUTHOR]

Bacterial endosymbionts that manipulate host reproduction are now known to be widespread in insects and other arthropods. Since they inhabit the cytoplasm and are maternally inherited, these microorganisms can enhance their fitness by biasing host sex ratio in favour of females. At its most extreme, sex ratio manipulation may be achieved by killing male embryos, as occurs in a number of insect species. Here, we provide evidence for the first case of male killing by a tetracycline-sensitive microbe in pseudoscorpions. Using a combination of inheritance studies, antibiotic treatment and molecular assays, we show that a new strain of Wolbachia is associated with extreme female bias in the pseudoscorpion, Cordylochernes scorpioides. In a highly female-biased line, sex ratio distortion was maternally inherited, and occurred in conjunction with a high rate of spontaneous abortion and low reproductive success. Antibiotic treatment cured females of the Wolbachia infection, restored offspring sex ratio to 1:1, and significantly enhanced female reproductive success. The discovery of apparent male-killing in C. scorpioides is of interest because pseudoscorpions are viviparous. Theory predicts that male killing should be favoured, if male death enhances the fitness of infected female siblings. In a live-bearing host, reallocation of maternal resources from dead male embryos to their sisters provides a direct, physiological mechanism through which fitness compensation could favour male killing by cellular endosymbionts. Our results suggest, however, that fitness compensation and the spread of male-killing endosymbionts may be undermined by a high rate of spontaneous abortion in infected females of this viviparous arthropod.Heredity (2005) 95, 41–49. doi:10.1038/sj.hdy.6800666 Published online 1 June 2005 [ABSTRACT FROM AUTHOR]

Summary: Many Collembola species are characterised by an aggregative behaviour, which is closely related to communication and co-ordination between individuals. In spite of a general heavy predation pressure, a large number of Collembola is found in soil suggesting that they have developed defence strategies against predators. This study investigates changes in spatial structure of gregarious Collembola species in presence of a predator. It is analysed if the gregarious lifestyle of Collembola populations functions as a defence strategy against predation. In presence of a predator distances between individuals in the Collembola species Folsomia candida and Heteromurus tetrophthalmus became closer, reducing the risk of individuals to be captured by predators. On the contrary, Onychiurus sinensis specimens, which were never caught probably because of the extrusion of repelling fluids by means of their pseudocelli, moved away from each another. Besides being a successful chemical defence against predation, repelling fluid secretion may effectively repel conspecifics, thereby keeping individuals at greater distance. [Copyright &y& Elsevier]

A total of 227 phoretic J3 dauer juveniles of the nematode Rhabditophanes schneideri (Bütschli) were observed attached to 63 out of 4845 specimens of three species of pseudoscorpion from Belgrade, Serbia and Montenegro. Analysis of the numbers of phoretic dauer larvae on different body regions revealed that the majority were attached to different pedipalpal and pedal segments. Only a few nematodes were carried on the prosoma and opisthosoma and none were observed on the chelicerae. [ABSTRACT FROM AUTHOR]

Following the first records of Chthonius (Ephippiochthonius) boldorii Beier, 1934 in central Europe, a species which was previously assumed to occur exclusively in Mediterranean caves, 116 series (595 specimens) of the cryptic taxa C. (E.) boldorii and C. (E.) fuscimanus Simon, 1900 (Syn. C. (E.) austriacus Beier, 1931) were re-examined. Although multivariate analyses suggest specific separation, there is only one unequivocal character for discrimination: the presence or absence of a single isolated tooth on the moveable finger of the chelicerae. The distributions were found to be largely allopatric, therefore it is concluded that the species rank of the two morphospecies is justified. North of the Alps, an almost vicariant pattern emerged: east of 14° E fuscimanus occurs, west of this line boldorii occurs. The results provide a basis for discussing the relevance of minute morphological differences in pseudoscorpion taxonomy. [ABSTRACT FROM AUTHOR]

Karyotypes of pseudoscorpions (Arachnida, Pseudoscorpiones) are largely unknown. Here we describe for the first time karyotypes of the suborder Epiocheirata, represented by 9 European species of two genera of Chthoniidae, Chthonius and Mundochthonius. Diploid chromosome numbers of males range from 21 to 37. Karyotypes of both genera differ substantially. Acrocentric chromosomes predominate in karyotypes of the genus Chthonius, whereas M. styriacus exhibits a predominance of metacentric chromosomes. These differences suggest that the two genera belong probably to distant branches of the family Chthoniidae. It is proposed that karyotype evolution of the genus Chthonius was characterised by a reduction of chromosome numbers by tandem and centric fusions as well as gradual conversion of acrocentric chromosomes to biarmed ones, mostly by pericentric inversions. A tendency towards reduced chromosome numbers is evident in the subgenus Ephippiochthonius. All species display X0 sex chromosome system that is probably ancestral in pseudoscorpions. The X chromosome exhibits conservative morphology. It is metacentric in all species examined, and in the majority of them, a subterminal secondary constriction was found at one of its arms. In contrast to chthoniids, secondary constriction was not reported on sex chromosomes of other pseudoscorpions. Analysis of prophase I chromosomes in males revealed an achiasmatic mode of meiosis. Findings of the achiasmatic meiosis in both genera, Chthonius and Mundochthonius, indicate that this mode of meiosis might be characteristic of the family Chthoniidae. Amongst arachnids, achiasmatic meiosis has only been described in some scorpions, acariform mites, and spiders. [ABSTRACT FROM AUTHOR]

The mating behavior of the cave pseudoscorpion Maxchernes iporangae Mahnert & Andrade, 1998 (Chernetidae), was studied under laboratory conditions. A total of 24 pairings was observed. Mating was divided into three phases: predeposition (dance), spermatophore deposition and transfer, and posttransfer phase. The mean mating duration was 67.3 min based on 10 observations. Spermatophore morphology is described and consists of a stalk, a drop of fluid, and an ∈-shaped sperm package. Males and females can mate several times in the same reproductive period. However, consecutive mating was not observed between a female and the same or another male. [ABSTRACT FROM AUTHOR]

We surveyed pseudoscorpion fauna in the soil organic layer in managed and abandoned secondary forests in Hiroshima Prefecture, Japan, and studied the effects of forest management on the pseudoscorpions. The vegetation structure was generally more developed in abandoned stands than in managed stands. The depth of the soil organic layer was not significantly different between the two stand types. We observed a total of seven pseudoscorpion species belonging to five genera. Pseudoscorpion species richness and densities were higher in abandoned stands than in managed stands. We did not find any pseudoscorpions in stands where the summed vegetation cover was less than 150%. [ABSTRACT FROM AUTHOR]

Examines the effects of spontaneous abortion on the sexual receptivity of female pseudoscorpions. Information on the trading-up hypothesis for polyandry; Factors influencing brood failure; Constraints on the ability of viviparous females to use polyandry for improving mating strategies.

Many beetles associated with old trees are on national red lists, but pseudoscorpions living in similar habitats have received little attention. This study reports the habitat and occurrence patterns of two species of pseudoscorpions living in hollow trees. Their occurrence has been assessed by sieving wood mould from 274 oaks in southeastern Sweden and from museum specimens collected in Sweden. Larca lata is confined to hollow oaks with a large girth and a plentiful supply of wood mould. Allochernes wideri is much less particular about wood mould volume, trunk diameter and tree species. Larca lata inhabits hollow trunks with characteristics that are typical of very old trees, whereas A. wideri predominantly occurs in trunks in an earlier stage of hollow formation. Larca lata was almost exclusively found in larger assemblages of hollow oaks, which suggests long-term survival may be difficult when the network of suitable hollow trees is too sparse. Larca lata is a rare species in Europe and probably vulnerable to extinction, since it is dependent on a habitat which has declined severely in the last few centuries. [ABSTRACT FROM AUTHOR]