Scorpion diversity in two different habitats in the Arid Chaco,Argentina

Scorpions are one of the most important taxa of predators in terms of density, biomass, and diversity in various areas of the world. In this study, we compared population- and community-level data between a mature and a secondary forest in the Chancaní Reserve (Córdoba, Argentina). Scorpions were collected using pitfall traps (54 nights per site), and their nocturnal activity was observed by means of UV light (26 nights per site) over 7 months. Seven species of scorpions (1964 individuals) were observed in the study area (Bothriuridae and Buthidae). Brachistosternus ferrugineus composed >74 % of all individuals and was numerically dominant in most months. It was the most common species sampled with UV light method in all months (85.73 % in mature and 81.80 % in secondary forest). Timogenes elegans was the most common species sampled with the pitfall traps method in secondary forest (48.58 %). General sex ratio (males:females) for B. ferrugineus was 1:1.24 and for T. elegans was 1:0.53. The Shannon index was not significantly different between sites. Species richness was similar, and the Jaccard index was Cs = 0.86, indicating that both sites share 86 % of the species. Tityus confluens was the only species not shared between sites. Our results indicate that species composition in regenerating forest resembles that of primary forest after c. 15 years, but the relative abundances of these species differ.     

Potential distribution patterns of scorpions in north‐eastern Brazil under scenarios of future climate change

Current predictions about the responses of species to climate change strongly rely on projecting altered environmental conditions on their distributions. In this study, we investigated the effects of future climate change scenarios on the potential distribution of 10 species of scorpions in north‐eastern Brazil in the context of their degree of specialisation to closed (Atlantic and Amazon Forests) and open (Caatinga and Cerrado) habitats. Scorpion species were classified as habitat specialists or generalists according to the IndVal index, and present and future species distribution models were prepared using minimum volume ellipsoids. According to IndVal, four species were classified as closed‐forest specialists (Ananteris mauryi, Tityus brazilae, Tityus pusillus and Tityus neglectus), four as open‐forest specialists (Jaguajir agamemnon, Jaguajir rochae, Physoctonus debilis and Bothriurus rochai), and two as generalists (Tityus stigmurus and Bothriurus asper). All species presented a drastic reduction in potential distribution, ranging from 44% to 72%, when compared with their current distribution. In addition, we found a reduction in scorpion species richness under future climate change scenarios. This finding has implications for scorpion conservation. Further, the results show that climate change may impact the composition of scorpion assemblages in north‐eastern Brazil, revealing important implications for human–scorpion interactions.     

Ecological modeling and distribution analysis of digger scorpions: Odontobuthus doriae,Odonthubutus bidentatus (Scorpiones: Buthidae) and Scorpio maurus (Scorpiones: Scorpionidae) in Iran using the maximum entropy method

Prediction models are essential for the potential geographic distribution of scorpions, prevention of scorpion stings and diverse applications in conservation biology. There is limited information about habitat suitability and the factors affecting the distribution of Iranian digger scorpions. This study was undertaken to model the distribution of three types of digger scorpion in Iran, Odontobuthus doriae Thorell, Odonthubutus bidentatus Lourenco (Scorpiones: Buthidae) and Scorpio maurus Pocockin (Scorpiones: Scorpionidae), and investigate the factors affecting its distribution using the maximum entropy method. A total of 20 environmental and climate variables were used for modeling and evaluation of the ecological niche. The similarities and differences between the ecological overlap of the digger scorpions were evaluated using comparative environmental niche model (ENM Tools software). The results showed that the main factors for habitat suitability of O. doriae were soil type, mean temperature of the wettest quarter and slope. The variables for S. maurus were soil type, precipitation of the coldest quarter and slope. Annual temperature range, mean temperature of the driest quarter and land use had the greatest influence on the distribution of O. bidentatus. The ecological niches for O. doriae and O. bidentatus overlapped. The niche of these species differed from the niche of S. maurus. This approach could be helpful for the prediction of the potential distribution of three digger scorpion species and this model can be an effective for the promotion of health.

     

Spatio-temporal microhabitat use by two co-occurring species of scorpions in Atlantic rainforest in Brazil

With the increasing devastation of the tropical rain forest, there is a critical need to understand how animal forest communities are structured and how habitat degradation will affect these communities. We conducted a field survey to investigate the microhabitat preferences of two co-occurring species of scorpions (Tityus pusillus and Ananteris mauryi) in a fragment of Atlantic rainforest, as well as their abundance and their ecological niche, during both the dry and rainy seasons. Behavioural aspects related to the use of the environment and the proportions of juveniles and adults are also described. The occurrence of intra- and interspecific coexistence was assessed by active search. In addition, pitfall catches were used to assess the structure of the population in the dry and rainy seasons. The differential patterns of spatial distribution in the litter layers provided evidence of partial niche partitioning between the two coexisting scorpion species depending on age and climatic conditions. Abundance, foraging behaviour and age structure (juveniles and adults) were seasonally influenced. We conclude that the diverse and subtle behaviours involved in interaction and habitat use may facilitate species coexistence. Resource partitioning and refuge sharing on a temporal and/or spatial scale, as well as predation pressure, may drive the dynamics and spatial distribution of scorpion species in the rain forest environment.     

Linking scorpion (Arachnida: Scorpiones) assemblage with fragment restoration in the Brazilian Atlantic Forest

Habitat loss due to forest degradation can induce changes in species richness due to variation in species susceptibility to environmental stress. This is particularly important for species with highly specific microhabitats, such as scorpions that inhabit forest habitats. In this study, the richness and abundance of these arachnids were compared between an old-growth (mature) and secondary (65 years under natural restoration) forests. Seasonal influence was also evaluated by comparing diversity between dry and wet seasons. The animals were collected through nocturnal active search using UV lamps and pitfall traps in both areas (old-growth and secondary). Both environments showed similar breast heights of trees, litter depth, litter dry mass, and understory density, indicating a high level of restoration. Scorpion diversity (characterized by Tityus pusillus, T. neglectus, T. brazilae, Bothriurus asper, and Ananteris mauryi) and abundance were not influenced by the different historical usage of both areas. In contrast, the abundance of these arachnids was highly affected by rain regimes, and increased during the dry season. These results suggest that 65 years was a sufficient time period for restoration, making it possible to maintain similar scorpion assemblages in both environments.     

Hemprich’s long-eared bat (<Emphasis Type="Italic">Otonycteris hemprichii</Emphasis>) as a predator of scorpions: whispering echolocation,passive gleaning and prey selection

Over 70% of the droppings of the gleaning bat Otonycteris hemprichii can contain scorpion fragments. Yet, some scorpions found in its desert habitat possess venom of the highest known toxicity, rendering them a very dangerous prey. In this study, we describe how O. hemprichii catches and handles scorpions, quantify its flight and echolocation behaviour in the field, investigate what sensory modality it uses to detect scorpions, and test whether it selects scorpions according to their size or toxicity. We confirmed that O. hemprichi is a whispering bat (approx. 80 dB peSPL) with short, multi-harmonic calls. In a flight room we also confirmed that O. hemprichii detects scorpions by their walking noises. Amplitudes of such noises were measured and they reach the flying bat at or below the level of echoes of the loess substrate. Bats dropped straight onto moving scorpions and were stung frequently even straight in their face. Stings did not change the bats’ behaviour and caused no signs of poisoning. Scorpions were eaten including poison gland and stinger. Bats showed no preference neither for any of the scorpion species nor their size suggesting they are generalist predators with regard to scorpions.     

The Life History of Chactas reticulatus Kraepelin, 1912 (Scorpiones, Chactidae), with a Comparative Analysis of the Reproductive Traits of Three Scorpion Lineages in Relation to Habitat

An account is given of the life history, growth, population densities, habitat, reproductive systems, courtship and mating, litter size and sex ratio, iteroparity, molting and development of the scorpion Chactas reticulatus Kraepelin. These same traits are compared in three distinct scorpion lineages, buthid, chactid and ischnurid in relation to habitat characteristics. Correlations are drawn between reproductive and adaptative strategies, and it is suggested that if non-buthid scorpions may present some homogeneity as equilibrium species, buthid scorpions are not necessarily opportunistic species. Many groups can be characterized within the buthids, and these different lineages show variable ecological requirements.     

Monitoring spatiotemporal variation in abundance and dispersal by a pheromone-kairomone system in the threatened saproxylic beetles <Emphasis Type="Italic">Osmoderma eremita</Emphasis> and <Emphasis Type="Italic">Elater ferrugineus</Emphasis>

Pheromone monitoring could provide unique spatial and temporal information about rare and threatened insect species for conservation purposes. Pheromone traps may be especially valuable in detecting fluctuations and declines in vulnerable species, if trap catch can be related to population density. We exploited the pheromone-kairomone system of the hermit beetle Osmoderma eremita and its predator, the red click beetle Elater ferrugineus, to monitor variation in their flight activity during 7 years (2001–2002, 2005–2009). Spatial and temporal flight activity of O. eremita and E. ferrugineus were highly correlated over individual trap replicates and trap days. Yearly flight activities of both species were correlated within two core sites included during all years of the study, and positively affected by temperature both within and between years. Flight activity could not be directly translated to variation in abundance in either species, however. Dispersal rate was likely the main factor explaining flight activity in O. eremita. Normalizing the flight activity of E. ferrugineus against that of O. eremita did not eliminate most of the variability, however, suggesting that flight activity of E. ferrugineus was governed both by dispersal rate and by population density. Higher fluctuations in population density of E. ferrugineus likely render it more vulnerable to local extinction, which may explain the greater rarity of this species. We suggest that preserving large assemblies of suitable hollow trees would be absolutely essential for buffering against stochastic population fluctuations and securing the long-term persistence of E. ferrugineus.     

Patterns of hemolymph osmoregulation in three desert arthropods

Summary Hemolymph osmoregulation was examined in three species of desert arthropods: a tenebrionid beetle,Eleodes hispilabris, a vejovid scorpion,Paruroctonus aquilonalis, and a spirostreptid millipede,Orthoporus ornatus. During desiccation, beetles regulated hemolymph osmolality and scorpions tolerated increasing osmolality. Millipedes displayed both osmotic regulation and tolerance patterns depending on sex and on duration of desiccation. Rehydration after desiccation depressed blood osmolality of male scorpions and beetles below levels found for freshly collected specimens. This was not the case in millipedes. Seasonal osmolality changes were studied and recorded among field-collected scorpions and beetles. Patterns of regulation and tolerance of hemolymph osmolality appear to vary among different kinds of desert arthropods.     

Diversity and seasonal composition of the scorpion fauna from a mountainous system on pampean grasslands in central Argentina

Scorpions are one of the most important taxa for ecological, conservation, and biogeographic studies. Biodiversity in the pampean grassland hilly environment is relevant because of the high number of native plant and animal taxa. We studied the diversity, abundance and phenology of a scorpion community in a natural reserve from central Argentina. Samples were taken monthly using 10 pitfall traps. Five species of scorpions (269 individuals) were observed in the study site (Bothriuridae). Bothriurus prospicuus was the most abundant species with 40.15% of the total individuals captured. The Shannon index was H´ = 0.69 and the evenness index was 0.83. Scorpion abundance was significantly different between months and was significantly correlated with monthly mean temperature. The knowledge on the scorpion fauna in “Ernesto Tornquist” Provincial Park could help in the preservation of natural grassland habitats.     

History of study,updated checklist,distribution and key of scorpions (Arachnida：Scorpiones) from China

This review describes the history of taxonomic research on scorpions and provides an updated checklist and key of the scorpions currently known in China. This checklist is based on a thorough review of the extant literatures on scorpion species whose presence has been confirmed in China through field expeditions and examination of scorpion collections, excepting a few members that have no clear distribution or are currently in doubt. Totally, the scorpion fauna of China consists of 53 species and subspecies belonging to 12 genera crossing five families, with 33 species (62.3%) and one genus being recorded as endemic. Additionally, identification key and the distribution of scorpions from China are provided.     

The effect of habitat fragmentation on the scorpion assemblage of a Brazilian Atlantic Forest

Habitat fragmentation is a topic widely studied in ecology; however, its effects on the assemblage of the order Scorpiones is less well understood. Aiming to fill this gap, this study assessed the effect of fragmentation on the assemblage of these arachnids in 12 Brazilian Atlantic forest fragments. Five environmental variables were measured (depth and dry mass of litter, understory density, canopy openness, and diameter at breast height of the trees), and the fragment area, vegetation cover, connectivity and elevation assessed. The animals were collected during the dry season and, identified at night with the use of ultraviolet light lamps. The analyzed scorpion assemblage in the landscape was characterized by the species Tityus pusillus, T. stigmurus, T. neglectus, T. brazilae, and Ananteris mauryi, with a maximum of three species co-occurring per fragment. Only the fragment size and the dry mass of litter showed a positive relationship with the composition of scorpions. These results suggest that the habitat of scorpions responds to environmental attributes and landscape metrics at both higher (fragment size) and lower (leaf litter) scales. Our study was able to expand our knowledge of how scorpions respond to habitat changes in the Atlantic Forest. We conclude that fragmentation and habitat quality are determining factors for the assemblage of these arachnids.     

Intra- and interspecific cohabitation of scorpions in the field and the effect of density, food, and shelter on their interactions

Scorpion cohabitation was studied qualitatively and quantitatively for several years in the field and in controlled experimental conditions in the laboratory. In the field, several cases were recorded of scorpions sharing the same shelter, either intra- or interspecifically. Intraspecific cohabitation was more prevalent than interspecific cohabitation. Among the five scorpion species studied here, Compsobuthus werneri judaicus shows the highest degree of sociality and aggregates both intra- and interspecifically. Leiurus quinquestriatus was never observed to cohabit interspecifically. Both Buthotus judaicus and C. werneri judaicus shared shelters with other scorpions more frequently during the wet season, whereas Nebo hierichonticus and Scorpio maurus fuscus cohabitated more often during the dry season. Under controlled laboratory conditions, density and availability of either food or shelter appear to be significant in facilitating cohabitation, even in the more aggressive species. Received: April 28, 1999 / Accepted: July 30, 1999     

Prey and feeding phenology of the desert sand scorpion Pamroctonus mesaensis (Scorpionidae: Vaejovidae)

The diet and feeding of the vaejovid scorpion Pamroctonus mesaensis Stahnke was investigated during a five-year study. Foraging and feeding behaviour are described. This scorpion is a "sit and wait" predator that eats a wide variety of cursorial, fossorial and aerial prey. Ninety-five prey species were recorded. Three year classes of scorpions exist. Each class captures a different proportion of major prey species and a significantly different average size of prey.
The proportion of each major taxon of prey in the diet is as follows: tenebrionid beetles (42%), Orthoptera (17%), other scorpions (16%) and Hymenoptera (12%). When analysed in relation to biomass, larger prey species assume more importance while smaller species are relatively less important. Although P. mesaensis ranks as the fourth most numerous prey species, they represent the most important diet item in terms of ingested biomass.
When observed, 3·75% of all scorpions were feeding. This percentage varied seasonally from a high in spring (7.0%) to a low in November and December (0.5 %). The proportions of major prey taxa in the diet also varied seasonally. Prey species were classified into three phenological categories: pulsed, seasonal and annual. Examples of each are given.     

Cryptic species and co‐diversification in sand scorpions from the Karakum and Kyzylkum deserts of Central Asia

Little is known about species diversification within the deserts of Central Asia. For example, the degree of lineage divergence and timing of population differentiation, as well as potential biogeographic barriers driving diversification, are nearly unknown. Here, we analysed a multi‐locus data set for a widespread sand scorpion (Mesobuthus gorelovi) to evaluate cryptic species diversity and phylogeographic patterns across the Karakum and Kyzylkum deserts. We also combined these data with previously published sequence data to test for a signal of co‐diversification. A consensus species delimitation approach indicated that the widespread M. gorelovi is likely composed of up to five distinct species that began to diversify at the Miocene–Pliocene boundary. We observed shared patterns of lineage divergence across the Amu Darya River region in three scorpion taxa and found support for a shared history of assemblage diversification across this biogeographic barrier. Thus, major river systems appear to facilitate diversification among desert scorpions.     

Some aspects of the biology of two common species of Nigerian scorpions

An account is given of the occurrence of Pandinus imperator imperator (C. L. Koch) and Buthus hottentotta hottentotta Fabricius which are two common species of scorpions in Nigeria. P. imperator is essentially a forest species commonly found in the lowland rain forest zone, while B. hottentotta typically lives in the savannah and has a much wider distribution stretching from the derived savannah to the Sudan zone. During aktograph experiments, P. imperator showed greater locomotory activity during the daytime than at night. In contrast, B. hottentotta was markedly nocturnal. The normal rhythm of locomotory activity of B. hottentotta was greatly affected by constant artificial illumination (20 foot candles) and constant darkness. The rate of water-loss of P. imperator in dry air was greater than that of B. hottentotta. The experimental results are discussed in relation to the behaviour of the scorpions in their natural habitats.     

Magellanic Woodpecker (Campephilus magellanicus) sap feeding and its role in the Tierra del Fuego forest bird assemblage

Several woodpecker species feed on phloem-sap flowing from pecked trees. We report sap consumption by the magellanic woodpecker (Campephilus magellanicus) inhabiting beech (Nothofagus) forests of Tierra del Fuego island (Chile). Magellanic woodpeckers drilled sap wells in N. betuloides trees close to their nests and also when they were moving in family groups. Three other bird species were observed foraging and competing for sap: the austral parakeet (Enicognathus ferrugineus) and two small passerines, the patagonian sierra-finch (Phrygilus patagonicus) and the white-crested elaenia (Elaenia albiceps). The abundance of these three bird species was greater in sites around sap wells than in other forest sites, suggesting that magellanic woodpecker is an important species in maintaining the Nothofagus forest bird assemblage.     

Singing in the rain. Rainfall and moonlight affect daily activity patterns of rodents in a Neotropical forest

Rainfall is often indirectly related to the availability of resources, which in turn regulates the abundance of rodents over time. However, the direct influence of rainfall on daily activity is poorly understood, despite the fact that it likely has a great effect on small animals. Furthermore, the influence of the moon on the movement of rodents has been the subject of debate but limited to studies conducted in open areas. Based on a study using pitfall traps in a subtropical region of southern Brazil, this study aimed to investigate the effects of rainfall and the phases of the moon on the daily movements of five species of sigmodontine rodents in a Neotropical forest. Activity patterns were assessed over 130 days, and the daily rainfall and moon phase were verified. Rainfall exhibited a significant positive effect on all studied species. This reflects an increase in the movement of rodents on rainy days, which should be primarily associated with the immediate harmful effects of rain, such as a wet coat and the destruction of shelters. The five species responded differently to moon phase, with a lack of effect for three of them and a positive effect of a full moon on the activity patterns of the other two species. This increase in activity rhythm due to a full moon may indicate a benefit of clear nights for foraging, in contrast to the most common outcome, which associates the brightness of the moon with increased predation risk.     

Molecular characterization of a new scorpion venom lipolysis activating peptide: Evidence for disulfide bridge-mediated functional switch of peptides

Venoms from scorpions contain extremely rich bioactive peptides that often carry diverse functions and are presumably needed to achieve synergistic effects for rapidly immobilizing prey and defending themselves. BotLVP1 is a unique heterodimer protein recently found in the scorpion Buthus occitanus tunetanus venom that is structurally related to scorpion toxins affecting sodium channels (NaScTxs) but exhibits adipocyte lipolysis activity. We have isolated and identified two cDNA clones encoding subunits and β of a BotLVP1-like peptide (named BmLVP1) from the Chinese scorpion Buthus martensii venom gland and determined the first complete gene structure of this subfamily. These results highlight a genetic link between these lipolysis activating peptides and NaScTxs. Comparison of cDNA and genomic sequences combined with protein structural and functional analysis provides evidence supporting the existence of RNA editing mechanism in scorpion venom glands, which could mediate functional switch of BmLVP1 gene, from adipocyte lipolysis to neurotoxicity, by altering the wrapper disulfide bridge (WDB) pattern of the peptides.     

Homology of the Lateral Eyes of Scorpiones: A Six-Ocellus Model

Scorpions possess two types of visual organs, the median and lateral eyes. Both eyes consist of simple ocelli with biconvex lenses that differ in structure and function. There is little variation in the number of median ocelli across the order. Except for a few troglomorphic species in which the median ocelli are absent, all scorpions possess a single pair. In contrast, the number of pairs of lateral ocelli varies from zero to five across Scorpiones and may vary within species. No attempt has been made to homologize lateral ocelli across the order, and their utility in scorpion systematics has been questioned, due to the variation in number. A recent study examined the number of lateral ocelli among various Asian Buthidae C.L. Koch, 1837 and proposed a “five-eye model” for the family. This model has not been examined more broadly within Buthidae, however, nor compared with the patterns of variation observed among other scorpion families. An eyespot, referred to as an accessory lateral eye, situated ventral or posteroventral to the lateral ocelli, has also been reported in some scorpions. Analysis of its structure suggests it serves a nonvisual function. We present the first comparative study of variation in the lateral ocelli across the order Scorpiones, based on examination of a broad range of exemplar species, representing all families, 160 genera (78%), 196 species (9%), and up to 12 individuals per species. We propose a six-ocellus model for Recent scorpions with four accessory ocelli observed in various taxa, homologize the individual ocelli, and correct erroneous counts in the recent literature. We also investigate the presence of the eyespot across scorpions and discover that it is more widespread than previously recognized. Future work should investigate the genetic and developmental mechanisms underlying the formation of the lateral ocelli to test the hypotheses proposed here.