Family Thomisidae Research Articles

Dominance structure and constancy of spiders in the Indian Thar desert

BackgroundThe knowledge about the species of a habitat (both resident and transient/dominant and rare) is a vital step to plan the conservation measures. Being generalist predators, spiders help controlling the population of their prey and maintain ecosystem stability. This makes spiders excellent bio-indicators for assessing the impact of anthropogenic disturbance factors on natural ecosystems (De, Siliwal, Uniyal and Hussain in Trop. Ecol. 63: 1–7, 2021). The aim of this study was to assess the dominance structure and constancy of spiders in three different habitats (Sand dunes, Riparian and Rocky) of the Thar desert. Study was conducted from March 2017 to February 2019 covering all seasons.ResultsThe eudominant species in sand dunes and rocky desert belonged to the family Thomisidae. These species were Tmarus sp. 1 and Tmarus kotigeharus Tikader, 1963, respectively. There were two eudominants in Riparian habitat (Oecobius putus O. Pickard-Cambridge, 1876 and Menemerus bivittatus (Dufour, 1831)). Through the analysis of constancy of all the species in the Thar desert, it was revealed that three species were constant in all the three habitats. The number of accessory and accidental species was far higher than constant species in all the habitats.ConclusionsThe number of accessory and accidental spider species in all habitats was far higher than constants due to the unstability of spider population. Therefore, this study highlights the necessity for conservation of these habitats of the Thar desert.

Faunistic and diagnostics of predaceous spiders in rice ecosystem under Terai region of West Bengal

Aim: Analyzing the community structure of predatory spider fauna in rice ecosystems to facilitate conservation biological control and sustainable pest management programmes. Methodology: The spiders were collected from rice field with cultivated variety (MTU-7029) during both Kharif and Rabi seasons at different rice growth stages. The spiders collected by various sampling methods such as direct catch in polythene carry bags, ground collection and foliage collection were kept in collection bottles and killed by inserting a strip of cotton dipped in chloroform and transferred separately on a white sheet of paper. Thereafter, using a stereo zoom microscope (ZEISS Stemi 508), the spiders were sorted, separated, counted, identified based on the available keys and literature described by Tikader (1987) and Barrion and Litsinger (1995). The unidentified samples were sent to the Zoological Survey of India, Kolkata for authorized identification. Results: In total, sixteen different species of predatory spiders belonging to six families of order Araneae and representing four functional/foraging guilds were identified in the rice ecosystem of Sub-Himalayan Terai region of West Bengal. These included Lycosa pseudoannulata Boesenberg & Strand and Arctosa tanakai Barrion & Litsinger; Oxyopes lineatipes C.L. Koch, Oxyopes javanus Thorell and Oxyopes salticus Hentz; Bianor sp. and Hasarius adansoni Audouin, while the family Thomisidae was represented by a single species Thomisius sp. All these eight species constituted the non web former group of spiders. The web weaving spiders recorded were Tetragnatha maxillosa Thorell, Tetragnatha mandibulata Walckenaer. Tetragnatha javana Thorell, Leucage decorate Walckenaer, Leucage celesbesiana Walckenaer and Neoscona theisi Walckenaer, Neoscona mukerjei Tikader, Araneus sp. Interpretation: The lynx spiders (Oxyopidae) were found to be the most dominant group by individual numbers, followed by the wolf spiders (Lycosidae), however, considering the species richness, the long jawed spiders (Tetragnathidae) were in large number with five different species. Good agricultural practices along with habitat diversification of landscapes are imperative for enhancing the predation by rice field spiders. Key words: Dominance, Foraging guilds, Predatory spiders, Rice, Species richness, Terai region

Check list of agrobiont spiders from citrus fields, Amravati region, MS, India

For one year, a research study was conducted in the citrus fields of Amravati region, MS, India, to examine the diversity of agrobiont spiders. A total of 56 species of agrobiont spiders were identified during the study, which belonged to 31 genera and 13 families. These spiders were found in various locations such as ground, litter, crevices, and on vegetation. Among the spider species identified, 21.42% were from the families Araneidae and Salticidae, respectively, 14.28% were from the family Lycocidae, 12.5% were from the family Oxyopidae, 7.14% were from the family Thomisidae, 5.35% were from the family Gnaphocidae, and 3.57% were from the families Clubionidae, Eradicate, and Philodromidae. Additionally, 1.78% of the spider species belonged to each of the following families: Mitergidae, Tetragnathidae, Theridadae, and Uloboridae. The spider population was abundant in the fields, and species richness and diversity were at their highest from August to October.

To the study of arachnids (Arachnida) – entomophages of lepidoptera pests of apple trees in the south-east of Kazakhstan

Nowadays, 81 species and 56 genera of arachnids belonging to 4 orders (Pseudoscorpionida, Trombidiformes, Opiliones and Aranei) and 19 families have been recorded in apple orchards of southeastern Kazakhstan. The order of spiders (Aranei) is dominant in diversity – 16 families, 54 genera and 73 species, the remaining orders include one family and 1-2 genera and species. According to the number of genera and species, the Araneidae family is dominant – 11 species and 9 genera. It is followed by the families Thomisidae (9 genera and 10 species), Salticidae (8 genera and 9 species), Lycosidae (5 genera and 9 species), Philodromidae (4 genera and 9 species), Theridiidae (3 genera and 5 species) and Gnaphosidae (4 genera and 4 species). Other families are represented by 1-2 genera and species. In general, the fauna of arachnid apple plantations, in which chemical pesticide treatments are used, is much more depleted (by 2 or more times) compared to gardens without such treatments and natural biotopes. Data on the consumption of pest caterpillars by different types of spiders in laboratory maintenance are given. Amaurobius erberi (Keyserling, 1863) ate up to 10 caterpillars of the codling moth Cydia pomonella (Linnaeus, 1758) or up to 5 caterpillars of the clouded drab Orthosia incerta (Hufnagel, 1766) per day. Steatoda paykulliana (Walckenaer, 1806) destroyed an average of 5 caterpillars of the codling moth or 3 caterpillars of the clouded drab per day. Smaller species, such as Diaea suspiciosa O.P.-Cambridge, 1885, Xysticus pseudocristatus Azarkina & Logunov, 2001 and Evarcha arcuata (Clerck, 1758), ate 2-3 caterpillars per day. For the first time in the apple orchard, the spider Olios sericeus (Kroneberg, 1875) was recorded, in Kazakhstan this species was previously noted as synanthropic.

Cytogenetics of entelegyne spiders (Arachnida, Araneae) from southern Africa.

Spiders represent one of the most studied arachnid orders. They are particularly intriguing from a cytogenetic point of view, due to their complex and dynamic sex chromosome determination systems. Despite intensive research on this group, cytogenetic data from African spiders are still mostly lacking. In this study, we describe the karyotypes of 38 species of spiders belonging to 16 entelegyne families from South Africa and Namibia. In the majority of analysed families, the observed chromosome numbers and morphology (mainly acrocentric) did not deviate from the family-level cytogenetic characteristics based on material from other continents: Tetragnathidae (2n♂ = 24), Ctenidae and Oxyopidae (2n♂ = 28), Sparassidae (2n♂ = 42), Gnaphosidae, Trachelidae and Trochanteriidae (2n♂ = 22), and Salticidae (2n♂ = 28). On the other hand, we identified interspecific variability within Hersiliidae (2n♂ = 33 and 35), Oecobiidae (2n♂ = 19 and 25), Selenopidae (2n♂ = 26 and 29) and Theridiidae (2n♂ = 21 and 22). We examined the karyotypes of Ammoxenidae and Gallieniellidae for the first time. Their diploid counts (2n♂ = 22) correspond to the superfamily Gnaphosoidea and support their placement in this lineage. On the other hand, the karyotypes of Prodidominae (2n♂ = 28 and 29) contrast with all other Gnaphosoidea. Similarly, the unusually high diploid number in Borboropactus sp. (2n♂ = 28) within the otherwise cytogenetically uniform family Thomisidae (mainly 2n♂ = 21–24) supports molecular data suggesting a basal position of the genus in the family. The implementation of FISH methods for visualisation of rDNA clusters facilitated the detection of complex dynamics of numbers of these loci. We identified up to five loci of the 18S rDNA clusters in our samples. Three different sex chromosome systems (X0, X1X20 and X1X2X30) were also detected among the studied taxa.

Description of female of Titidius urucu Esmerio Lise, 1996 (Araneae: Thomisidae).

The genus Titidius Simon, 1895 belongs to the family Thomisidae Sundevall, 1833 and can be easily identified from the related genera Tmarus Simon, 1875 and Acentroscelus Simon, 1886 by the high carapace, anterior eye row straight and posterior eye row recurve-;pd in dorsal view, carapace smooth with moderate setation, abdomen longer than wide, legs long, slender and setose and clypeus vertical (Esmerio Lise 1996). It is currently composed of 20 species, all occurring in Brazil with exception of Titidius ignestiiCaporiacco, 1947 from Guyana (World Spider Catalog 2017). Eight species are distributed in the Amazon region (Esmerio Lise 1996): T. caninde Esmerio Lise, 1996, T. gurupi Esmerio Lise, 1996, T. multifasciatus Mello-Leitão, 1929 and T. rubrosignatus (Keyserling, 1880) from Pará; T. galbanatus (Keyserling, 1880) from Amazonas and Pará; T. quinquenatus Mello-Leitão, 1929 and T. urucu from Amazonas; and T. rubescens Carporiacco, 1947 from Amazonas and Roraima.

Redescription of the poorly known crab spider Xysticus spasskyi(Araneae: Thomisidae).

With 372 species, Xysticus C.L. Koch, 1835 is the largest genus in the family Thomisidae (WSC 2016). As with other speciose genera, the genus has never been revised on a global scale and is only thoroughly known in a few parts of the Holarctic, namely Central and Northern Europe, North America, Israel and Japan. Over 200 species are known from one/two taxonomic references only, or from a single illustrated description/redescription (WSC 2016). The fact that 40% of species are known from only one sex (104 females and 54 males) or from juveniles (8 species) (WSC 2016) suggests that Xysticus requires revision. During a study of crab spiders of the Caucasus, we experienced difficulties in identifying Xysticus spasskyi Utochkin, 1968 due to the lack of detailed figures of the male palp and female epigyne. This species was based on the holotype female collected from an unspecified locality in the coastal part of modern Kransnodar Province (Utochkin 1968). The male of X. spasskyi was described as X. umbrinus Utochkin, 1968 from Kuban' Region (currently Krasnodar Province). The two species were synonymised by Ovtsharenko (1979). Besides Krasnodar Province, the species has been reported from North Ossetia (Ponomarev & Komarov 2013) and South Ossetia (Ponomarev & Komarov 2015), Georgia, Azerbaijan and the Crimea (Mikhailov 2013; Otto 2015). The illustrations in the descriptions of Utochkin (1968) and Ovtsharenko (1979), are either very small, schematic or provide no diagnostic details. The endogyne (=vulva) of this species has never been illustrated. Here we redescribe this species and compare distant populations.

Surrogates of spider diversity, leveraging the conservation of a poorly known group in the Savanna Biome of South Africa

The inclusion of spiders in conservation planning initiatives is confounded by several factors. Surrogates could facilitate their incorporation. In this paper we investigate the performance of a number of surrogate measures, such as higher taxa (genus, family), cross-taxon surrogates that are subsets of the spider assemblages (certain spider families) or non-overlapping groups (woody vegetation and birds), and the use of morphospecies. Birds and woody vegetation were included because they often form the focus of conservation planning initiatives. We assessed the surrogate measures based on their predictive power for species richness and extent to which conservation planning that maximizes representation of the surrogate is effective in representing spider diversity. A measure for the latter is the Species Accumulation Index (SAI). Generic richness as a higher taxon surrogate and the combined richness of the families Thomisidae and Salticidae were the best estimators of total species richness. Based on the surrogacy efficiency criterion, genera and the family Salticidae had species accumulation indices (SAIs) that were significantly larger than 95% confidence intervals of a random curve, while woody vegetation and birds turned out to be poor surrogates for spider diversity. The use of morphospecies as estimators is cautiously supported (adjusted R2=0.85, for species richness, SAI=0.73). The surrogates identified here provide a viable alternative to whole assemblage analysis but should be used with caution. The use of genera is confounded by unstable taxonomy and the difficulty of identifying specimens up to genus level. Geographic location and varying sampling effort between surveys did not have an effect on the surrogate performance of the two spider families, viz. Salticidae and Thomisidae. The former family has seen a flood of recent systematic work, whereas the latter’s taxonomy is fairly well developed. These two families comprise ca. 20% of spider species observed in the Savanna Biome of South Africa and could provide a viable handle on spider diversity in this region.

Three new spider species of the family Thomisidae from Hong Kong (Arachnida: Araneae)

Three new species of spiders from farmland and nearby non-crop fields at Tai Lung Experimental Station (TLES), Hong Kong, were discovered. All three new species occurred in the family Thomisidae, they are Diaea simplex Xu, Han & Li sp. n., Massuria bellula Xu, Han & Li sp. n. and Mastira tegularis Xu, Han & Li sp. n. Descriptions and illustrations of the new species are provided.

Redescription of Australian crab spider Diaea pulleinei Rainbow, 1915 (Araneae: Thomisidae)

Species richness of described crab spiders (Family Thomisidae) in Australia is low. Altogether 123 species of the family are known from this continent. One of the most abundantly represented genera of crab spiders in Australia is Diaea (31 recognized species). This paper revises knowledge of one species of this genus, Diaea pulleinei Rainbow, 1915, supplementing its description with the hitherto unknown female.

Crab spiders of the families Thomisidae and Philodromidae (Arachnida: Araneae) from Iran

Spiders of the families Thomisidae and Philodromidae (Arachnida, Araneae) mainly collected in the mountainous areas of Iran in 1978 are taxonomically studied and classified into 21 species of 10 genera. Most species are illustrated and described on the basis of the present specimens. Except for only two species, Xysticus kulczynskii Wierzbicki 1902 and Synaema globosum (Fabricius 1775), already known from this country, 19 species are new records to the Iranian fauna. Of these, 14 species, Tmarus stellio Simon 1875, Xysticus ninnii Thorell 1872 (subsp. fusciventris Crome 1965), X. cristatus (Clerck 1758), X. kochi Thorell 1872, X. gallicus Simon 1875, Oxyptila nigrita Thorell 1875, Heriaeus spinipalpus Loerbroks 1983, Misumena vatia (Clerck 1758), Pistius truncatus (Pallas 1772), Runcinia lateralis (C. L. Koch 1838), Thomisus hilarulus Simon 1875, Philodromus longipalpis Simon 1870, P. cespitum (Walckenaer 1802), and P. emarginatus (Schrank 1803), are previously known to science, while five species are regarded as new and described under the names Xysticus marusiki, X. logunovi, X. pieperi, Oxyptila makidica, and O. lutosa.

A new species of the genus Lysiteles (Araneae: Thomisidae) from Hainan Island, China

A new species of the spider family Thomisidae from Jianfeng National Nature Reserve, Ledong County, Hainan Province (Hainan Island), China, is described under the name of Lysiteles anchorus. The new species resembles Lysiteles ambrosii Ono 2001, from Bhutan and L. okumae Ono 1980 from Japan, but can be distinguished from these known species by having a pair of lateral pockets on epigynum and by the unique structure of male palp, especially the anchor-shaped embolus and the huge, retrolateral apophysis on tibia.

La comunidad de arañas del cultivo de soja en la provincia de Buenos Aires, Argentina

Las arañas son uno de los depredadores más numerosos y un importante factor de mortalidad de insectos plaga de cultivos. La comunidad de arañas se muestreó mediante embolsado de plantas, red de arrastre, trampas de caída y captura manual a lo largo de 2h, en cultivos de soja y en los bordes con vegetación natural. Los muestreos se realizaron durante el desarrollo del cultivo (Diciembre-mediados de Mayo) y el período de barbecho (mediados de Mayo-Noviembre), con el fin de conocer la composición específica, comparar la diversidad mediante el índice de Shannon, y analizar la colonización del cultivo. La riqueza específica total fue de 37 especies agrupadas en 13 familias y la dominante fue Misumenops pallidus (Keyserling) (Thomisidae). La mayor diversidad se detectó en la vegetación natural (H = 2,829 y 25 especies), luego en el estrato herbáceo del cultivo con el que mostró la mayor afinidad (H = 2,140 y 28 especies) y la menor diversidad se detectó durante el período de barbecho (H = 1,050, y 12 especies). Las primeras colonizadoras del cultivo (Diciembre) fueron Thomisidae, Anyphaenidae y Oxyopidae, luego Araneidae y Corinnidae y última Salticidae. Thomisidae fue siempre la más abundante con predominio desde Febrero a Abril. En Diciembre se encontró una muy baja densidad de arañas en el borde del cultivo, y desde Enero a Marzo la distribución del borde al centro no mostró gradiente alguno. La presencia de varias especies pertenecientes a diferentes gremios en todo el lote sugiere un importante efecto limitador de las arañas sobre las poblaciones de insectos, así como la importancia de las áreas naturales en técnicas de control biológico por conservación.

Spiders of the family Thomisidae from Sakhalin and the Kurile Islands.

Materials of the thomisid spiders collected in Sakhalin and the Kurile Islands are studied. They are classified into 19 species including a new one described under the name of Oxyptila sakhalinensis. Female and male sexual organs of most of the species are illustrated. Zoogeographical notes are given on the basis of the present materials.

Energy Content of Some Spiders and Insects on Branches of Spruce (Picea abies) in Winter; Prey of Certain Passerine Birds

Spiders and some insects were collected from branches of spruce, Picea abies, in September-October and February-March in southwest Sweden. At least 19 species of spiders were present. Spiders of family Thomisidae were most common with 37-45% by number, and the species-group Philodromus aureolus alone made up 35-39%. Family Linyphiidae came second with 27% and Araneidae third with 11-20%. The taxonomic composition is remarkably similar in September and March. This suggests that the birds, which severely reduce spider density over winter, prey on spiders with little or no selectivity as to taxonomy. A fitted power function of fresh body mass versus length has the exponent 2.39; this indicates that spiders of different size are geometrically dissimilar. In autumn the energy content per gram of dry mass is 24.0 kJ for spiders, 21.7 kJ for Psocoptera, and 22.0 kJ for Curculionidae. Average energy content per gram of dry mass of spiders decreased by 5.8% in four winter months. If this reduction is assumed to be caused by metabolism of stored fat only, the corresponding reduction of dry mass per spider would be 8.1% and the reduction of energy content per spider 13%. The energy cost of standard metabolism of spiders over winter was calculated to be a considerably larger proportion of the energy content of spiders in autumn.

Invertebrate Predators of the Jack-Pine Bud worm, Choristoneura pinus,1in Michigan2

Invertebrate predators of Choristoneura pinus Freeman (Lepidoptera: Tortricidae) were studied in the laboratory and observed under field conditions in an investigation of their feeding response and behavior. Observations were made on the biology of important predators in northern anil central Michigan. The distribution, number, and kinds of spiders associated with 6 jack pine trees were investigated in Baraga County. Eight species of insects were recorded preying on various stages of C. pinus. Anatis occllata (L.), Podisus sereventris Uhler, and Camponotus novchoracensis Fitch were the most abundant of this group. Field observations suggested that populations of P. serieventris exhibited a numerical response to increases in buclworm numbers. Fifty-one species of spiders were collected from jack pine trees. Three-quarters of them were hunting spiders that belonged to the families Thomisidae, Salticidae, and Oxyopidae. One species, Metaphidippus flavipedes Peckham, accounted for 48.0% of this group. Theridion murarium Emerton, Dictyna phylax Gertsch ' Ivie, and Grammonota pictilis O. P.-Cambridge were the most common web-spinners encountered. Observations suggested that defoliation and natural stand closure are factors that limit populations of spiders in jack pine stands. No crown level or type of stand could be characterized by specific groups or species.

Studies on some crab-spider (Family: Thomisidae) from Khasi and Jaintia Hills, Assam, India

Five new species of spiders are described in this paper. Most of the species were collected from Khasi and Jaintia Hills, Assam. The new species belong to four genera distributed in the family Thomisidae.

On some new species of spiders of the family thomisidae from India

Eleven new species of spiders are described in this paper. Most of the species were collected from Poona District, Maharashtra, and one species collected from Mussoorie, U.P., India. The new species belong to seven genera distributed in the family Thomisidae.

Studies on interesting South Indian crab-spiders (Family: Thomisidae)

Eleven new species of spiders are described in this paper. All were collected from Maharashtra and Mysore States, India. The new species belong to nine genera distributed in the family Thomisidae.

Studies on some Indian Spiders (Araneae: Arachnida)

Summary Twenty-six species of spiders are described in this paper. Of these, 12 are known and 14 are new to science. The new species belong to ten genera distributed in the families Thomisidae, Clubionidae, Agelenidae, Argiopidae.