Abstract Background: Scorpions can use their pincers and/or stingers to subdue and immobilize their prey. A scorpion can thus choose between strategies involving force or venom, or both, depending on what is required to subdue its prey. Scorpions vary greatly in the size and strength of their pincers, and in the efficacy of their venom. Whether this variability is driven by their defensive or prey incapacitation functionis unknown. In this study, we test if scorpion species with different pincer morphologies and venom efficacies use these weapons differently during prey subjugation. To that end, we observed Opisthacanthus elatus and Chactas sp. with large pincers and Centruroides edwardsii and Tityus sp. with slender pincers. Methods: The scorpion pinch force was measured, and behavioral experiments were performed with hard and soft prey (Blaptica dubia and Acheta domesticus). Stinger use, sting frequency and immobilization time were measured. Results: We found that scorpions with large pincers such as O. elatus produce more force and use the stinger less, mostly subjugating prey by crushing them with the pincers. In C. edwardsii and Tityus sp. we found they use their slender and relatively weak pincers for holding the prey, but seem to predominantly use the stinger to subjugate them. On the other hand, Chactas sp. uses both strategies although it has a high pinch force. Conclusions: Our results show that scorpionspecies with massive pincers and high pinch force as O. elatus use the stinger less for prey subjugation than scorpionspecies with slenderpincers.

Abstract Background: Scorpions are widely known for the neurotoxic effects of their venoms, which contain peptides affecting ionic channels. Although Colombia is recognized for its scorpion diversity, only a few studies are available describing the venom content. Methods: In this descriptive study, we analyzed the MS/MS sequence, electrophoretic and chromatographic profile linked to a bioinformatics analysis of the scorpions Chactas reticulatus (Chactidae), Opisthacanthus elatus (Hormuridae), Centruroides edwardsii (Buthidae) and Tityus asthenes (Buthidae) from Colombia. Results: Each scorpion showed a specific electrophoretic and chromatographic profile. The electrophoretic profiles indicate the presence of high molecular mass compounds in all venoms, with a predominance of low molecular mass compounds in the Buthidae species. Chromatographic profiles showed a similar pattern as the electrophoretic profiles. From the MS/MS analysis of the chromatographic collected fractions, we obtained internal peptide sequences corresponding to proteins reported in scorpions from the respective family of the analyzed samples. Some of these proteins correspond to neurotoxins affecting ionic channels, antimicrobial peptides and metalloproteinase-like fragments. In the venom of Tityus asthenes, the MSn analysis allowed the detection of two toxins affecting sodium channels covering 50% and 84% of the sequence respectively, showing 100% sequence similarity. Two sequences from Tityus asthenes showed sequence similarity with a phospholipase from Opisthacanthus cayaporum indicating the presence of this type of toxin in this species for the first time. One sequence matching a hypothetical secreted protein from Hottentotta judaicus was found in three of the studied venoms. We found that this protein is common in the Buthidae family whereas it has been reported in other families - such as Scorpionidae - and may be part of the evolutionary puzzle of venoms in these arachnids. Conclusion: Buthidae venoms from Colombia can be considered an important source of peptides similar to toxins affecting ionic channels. An interesting predicted antimicrobial peptide was detected in three of the analyzed venoms.

Abstract Scorpion species often occur in sympatry, especially in tropical forests. Here, we analyse aspects of the intraguild interactions occurring between Centruroides limbatus (Pocock, 1898) and Tityus ocelote Francke & Stockwell, 1987 (Buthidae) in a tropical forest of Costa Rica. We divided the study in 2 areas: north and south. Results show differences in abundance and distribution of C. limbatus (north = 16, south = 8) and T. ocelote (north = 2, south = 37); a major frequency of females for both species (74% ♀ and 26% ♂ in C. limbatus, 78% ♀ and 22% ♂ in T. ocelote; 55 sexed scorpions); similar microhabitat preferences (trees with vines, palms) and significant differences (p = 0.037) in the height at which both species were located above ground in each zone. Significant differences in height between zones showed disparity in habitat selection (north and south), whereas non-significant differences in height between species indicated niche overlap in those areas where they coexist, confirmed by the Morisita index for niche overlap in the southern zone (M-NO = 0.686). Cannibalism was reported in C. limbatus. These intraguild interactions indicate the existence of some level of competition between these scorpions.

Resumen Las especies de escorpión coexisten en simpatría, especialmente en bosques tropicales. Aquí analizamos algunos aspectos de las interacciones intragremio entre Centruroides limbatus (Pocock, 1898) y Tityus ocelote Francke y Stockwell, 1987 (Buthidae) en un bosque tropical de Costa Rica. Dividimos el estudio en 2 áreas: norte y sur. Los resultados mostraron diferencias en abundancia y distribución de C. limbatus (norte = 16, sur = 8) y T. ocelote (norte = 2, sur = 37); mayor frecuencia de hembras en ambas especies (74% ♀ y 26% ♂ en C. limbatus, 78% ♀ y 22% ♂ en T. ocelote; 55 escorpiones sexados); preferencias de microhábitat similares (árboles con lianas, palmeras) y diferencias significativas (p = 0.0037) en la altura a la que ambas especies se encontraban en cada zona. Las diferencias significativas en la altura entre zonas mostraron disparidad en selección de hábitat (norte y sur), mientras que las diferencias no significativas en la altura entre especies mostraron solapamiento de nicho en áreas dónde coexistían, confirmado por el índice de Morisita para solapamiento de nicho en la zona sur (M-NO = 0.686). Se reportó canibalismo en C. limbatus. Estas interacciones intragremio manifiestan la existencia de cierto nivel de competencia entre estos escorpiones.

Abstract Introduction: Scorpion stings represent a public health problem in Latin America and North America. The aim of this study was to identify species of medical importance, as well as to estimate the frequency of scorpion sting and the associated risk and protective factors in schoolchildren. Methods: Cross-sectional study in two rural communities in the Mexican state of Guerrero, in two phases: an entomological study that estimated the scorpion density and overcrowding index; a survey to document housing characteristics, poultry ownership, and history of scorpion sting in schoolchildren. Adjusted odds ratio (ORa) was used as a measure of association with scorpion sting in a multivariate analysis. Results: The species of medical importance were Centruroides limpidus and Centruroides balsasensis. Twelve percent (171/1,437) of school children reported scorpion sting in the last six months, of whom seven out of ten required medical care. Four factors were associated with the report of scorpion sting: having ducks in the dwelling (ORa: 1.98; CI 95%: 1.2-4.29), lack of cleanliness in the dwelling (ORa: 1.84; CI 95%: 1.02-4.16), farming as an occupation (ORa: 1.53; CI 95%: 1.13-2.46) and dwelling with uncovered infrastructure of the roof, those made of wood/iron sheet or cardboard (ORa: 1.42; CI 95%: 1.04-2.18). Conclusions: The most relevant species was Centruroides limpidus. Two factors might be particularly relevant to prevention: improvement of household roofing material and attention to housekeeping.

Resumen Introducción: La intoxicación por picadura de alacrán es un problema de salud pública en las regiones de América Latina y América del Norte. El objetivo de este estudio fue identificar especies de alacrán de importancia médica, estimar la ocurrencia de accidentes por picadura de alacrán y factores asociados en la población de edad escolar. Métodos: Estudio transversal en dos comunidades rurales de Guerrero, México, en dos fases: el estudio entomológico para estimar índices escorpionológicos y la encuesta a escolares que incluyó las características de sus viviendas, la tenencia de aves, los antecedentes de picadura de alacrán y variables relevantes. Se estimó la razón de momios ajustada (RMa) como medida de asociación al accidente por picadura de alacrán en los escolares mediante análisis multivariado. Resultados: Las especies de importancia médica fueron Centruroides limpidus y Centruroides balsasensis. El reporte de accidente por picadura de alacrán en los últimos 6 meses en escolares fue del 12 % (171/1,437). Siete de cada diez escolares requirió de atención médica. Fueron identificados cuatro factores asociados con el reporte de accidente por picadura de alacrán: tener patos en la vivienda (razón de momios ajustada [RMa]: 1.98; intervalo de confianza [IC] 95 %: 1.2-4.29), falta de aseo en la vivienda (RMa: 1.84; IC 95 %: 1.02-4.16), ayudar en la labor del campo (RMa: 1.53; IC 95 %: 1.13-2.46) y viviendas con material del techo no permanente (RMa: 1.42; IC 95 %: 1.04-2.18). Conclusiones: Centruroides limpidus fue la especie de importancia médica más relevante. Fueron identificados dos factores asociados que son potencialmente modificables: mejorar el material del techo de la vivienda y asear la vivienda.

Abstract Centruroides lauriadnae sp. n. is described from Sonora State, Mexico. This species belongs to the so called “striped” group in the genus (sensuHoffmann, 1932). It is compared with the 2 other species recorded for Sonora: C. pallidiceps Pocock and C. sculpturatus Ewing, as well as compared with C. suffusus (Pocock) of northern México.

Resumen Se describe Centruroides lauriadnae sp. n. del estado de Sonora, México, perteneciente al grupo de los llamados alacranes “rayados” dentro del género (sensuHoffmann, 1932). Se compara con las 2 especies del género registradas para Sonora: C. pallidiceps Pocock y C. sculpturatus Ewing, así como con C. suffusus (Pocock) del norte de México.

Abstract I present a photographic sequence of how the snake Stenorrhina degenhardtii captures and eats the scorpion Centruroides bicolor.

Resumen Presento una secuencia fotográfica de cómo la serpiente Stenorrhina degenhardtii captura y come al escorpión Centruroides bicolor.

Abstract Background Centruroides hirsutipalpus, of the family Buthidae, is a scorpion endemic to the Western Pacific region of Mexico. Although medically important, its venom has not yet been studied. Therefore, this communication aims to identify their venom components and possible functions. Methods Fingerprinting mass analysis of the soluble venom from this scorpion was achieved by high-performance liquid chromatography and electrospray mass spectrometry. Furthermore, the soluble venom and its toxic effects were evaluated extensively via electrophysiological assays in HEK cells expressing human voltage-gated Na+ channels (hNav 1.1 to Nav1.6), CHO cells expressing hNav 1.7, potassium channel hERG 1 (Ether-à-go-go-related-gene) and the human K+-channel hKv1.1. Results The separation of soluble venom produced 60 fractions from which 83 distinct components were identified. The molecular mass distribution of these components varies from 340 to 21,120 Da. Most of the peptides have a molecular weight between 7001 and 8000 Da (46% components), a range that usually corresponds to peptides known to affect Na+ channels. Peptides with molecular masses from 3000 to 5000 Da (28% of the components) were identified within the range corresponding to K+-channel blocking toxins. Two peptides were obtained in pure format and completely sequenced: one with 29 amino acids, showing sequence similarity to an "orphan peptide" of C. limpidus, and the other with 65 amino acid residues shown to be an arthropod toxin (lethal to crustaceans and toxic to crickets). The electrophysiological results of the whole soluble venom show a beta type modification of the currents of channels Nav1.1, Nav1.2 and Nav1.6. The main effect observed in channels hERG and hKv 1.1 was a reduction of the currents. Conclusion The venom contains more than 83 distinct components, among which are peptides that affect the function of human Na+-channels and K+-channels. Two new complete amino acid sequences were determined: one an arthropod toxin, the other a peptide of unknown function.

ResumenExisten alrededor de 2 000 especies de escorpiones en el mundo y a pesar de que muy pocas de ellas son consideradas peligrosas para el ser humano se presentan muchos casos de escorpionismo alrededor del mundo. La elaboración de suero antiescorpiónico requiere en primera instancia del establecimiento de una colección en cautiverio para la extracción del veneno, razón por la cual el Instituto Clodomiro Picado (ICP), con una amplia trayectoria en la elaboración de suero antiofídico, inicia en el 2005 una colección para dicho fin. En total 2 043 escorpiones clasificados en 11 especies fueron recolectados en un periodo de siete años mediante búsqueda intensiva con luz ultravioleta en varias localidades de la vertiente Pacífica, así como la vertiente Atlántica de Costa Rica. Las extracciones de veneno se realizaron con electro-estimulación, y el veneno recolectado fue caracterizado por el contenido total de proteínas, además se realizaron pruebas de letalidad, siendo Centruroides bicolor el más letal y el que presento los valores más altos en cantidad de veneno y proteínas totales lo cual es consecuente con su masa corporal. Las técnicas empleadas en el mantenimiento en cautiverio de los escorpiones permitieron que los escorpiones vivieran varios años, en un análisis de la longevidad se obtuvieron diferencias significativas entre los géneros (H = 353.80; g.l = 3; P < 0.0001), siendo el género Didymocentrus el más longevo con un promedio de 4.46 años, un factor importante de su longevidad es el hecho de no haber formado parte del proceso de extracción. También se pudo evidenciar una alta supervivencia de crías nacidas en cautiverio de la especie Tityus pachyurus con respecto a las otras especies del mismo género (H = 94.32; g.l = 3; P < 0.0001), resultado que puede ser tomado en cuenta para reproducir esta especie en cautiverio. El mantenimiento de la colección de escorpiones fue eficiente para el proceso de extracción de veneno y para una supervivencia prolongada de los animales. Existen muy pocas publicaciones en lo que se refiere al mantenimiento de escorpiones en cautiverio para la extracción de veneno por lo que se requiere de una investigación más profunda en aspectos como la reproducción, las causas de muerte y la alimentación.

Abstract:Approximately 2 000 scorpion species can be found around the world; although few species are considered “harmful” to human beings, a high number of scorpionism cases are reported all over the world. The elaboration of anti-scorpion sera requires the establishment of an animal collection maintained in captivity for venom extraction purposes. The Clodomiro Picado Institute (ICP, for its acronym in Spanish), poses a vast trajectory in manufacturing snakebite antivenoms, and starts a scorpion collection in 2005 for this purpose. In total, 2 043 scorpions were classified in 11 species and collected during a seven-year period using a black-light flashlight and an intensive seeking methodology. The scorpions were collected from several localities of the Pacific and the Caribbean versants of Costa Rica. The venom extraction was performed by applying electrostimulation; the collected venom was characterized by total protein content in addition to median lethal doses. Centruroidesbicolor showed higher amounts of venom yield, total protein content and more lethal dose, all of which were correlated with its body mass. The techniques used to keep scorpions in captivity allowed the animals to live several years. Longevity analysis showed significant differences among scorpion genera (H= 353.80; df= 3; P < 0.0001); moreover, the genus Didymocentrus lived longer with an average of 4.46 years. One key factor of its longevity was that it did not go through venom extraction processes. Additionally, a high survival rate of Tityuspachyurus born in captivity, compared to other species within the same genus, was observed (H= 94.32; df= 3; P < 0.0001). This characteristic should be taken into consideration, when programs of reproduction in captivity are designed. In conclusion, the maintenance of a scorpion collection was efficient for venom extraction purposes and a longer life expectancy of the animals. Moreover, there is a scarcity on publications regarding scorpion maintenance in captivity for venom extraction purposes; therefore, a deeper research in aspects such as reproduction, death causes and feeding behaviors is required. Rev. Biol. Trop. 64 (3): 1019-1027. Epub 2016 September 01.

Centruroides ruana sp. nov. is described from Felipe Carrillo Puerto, from the Buenavista Municipality in the state of Michoacán, Mexico. The new species was compared with C. balsasensisPonce-Saavedra & Francke, 2004, C. infamatus Koch, 1844, and C. limpidus (Karsch, 1879), which are both morphologically its closest relatives and geographically proximate. The description includes the male holotype, with 7 male and 8 female paratypes. A supplementary morphometric analysis is also presented allowing to distinguish the 4 species.

Se describe Centruroides ruana sp. nov. de Felipe Carrillo Puerto, municipio de Buenavista en el estado de Michoacán, México. Se hace una comparación con las especies morfológica y geográficamente más cercanas: C. balsasensisPonce-Saavedra y Francke, 2004, C. infamatus Koch, 1844 y C. limpidus (Karsch, 1879). La descripción incluye el macho holotipo, 7 machos y 8 hembras paratipos. Se presenta un análisis morfométrico que también permitió diferenciar las 4 especies.

AbstractCentruroides margaritatus is one of the most common scorpions in Costa Rica, however almost null ecological or population-based studies have been conducted. Therefore, the objective of the present study was to characterize the habitat use and surface activity of this species in Palo Verde National Park, Costa Rica. Scorpions were searched intensively along transects at three sites: road, camp and forest. The microhabitat in each capture was characterized and the surface activity of the scorpions was recorded at the time of capture. C. margaritatus was found in different microhabitats: soil, leaf litter, herbaceous plants, shrubs, trees, and under rocks and fallen logs, with a preference to use vegetation to heights less than 50 cm. The scorpions were in an ambush behavior most of the times and were observed mostly in the vegetation, while they were in a resting behavior mainly under fallen trunks and rocks. The use of vegetation can represent a strategy to obtain food and also be in a safe place against predators. Nevertheless, the species adaptability provides the ease of using many microhabitats in sites where vegetation is scarce. While the study period was short, this research provides the first observations about the habitat use of this species in Costa Rica, which serves as a basis for future investigation.

Resumen Centrutoides margaritatus es uno de los escorpiones más comunes en Costa Rica, pese a esto en este país no se han realizado estudios ecológicos ni poblacionales. Por lo tanto, se pretendió caracterizar el uso del hábitat y actividad superficial de esta especie en el Parque Nacional Palo Verde. El muestreo de los escorpiones se realizó mediante búsqueda intensiva a lo largo de transectos en tres sitios: carretera, campamento y bosque. Se caracterizó el microhábitat en el cual se encontraba cada individuo y se observó la actividad superficial que estaban realizando los escorpiones en el momento de la captura. C. margaritatus se encontró en diferentes microhábitats: suelo, hojarasca, herbáceas, arbustos, árboles, y debajo de rocas y troncos caídos, con una preferencia a utilizar la vegetación a alturas menores a 50 cm. El acecho fue el comportamiento más frecuente y fue observado mayormente en la vegetación, mientras que el descanso se encontró principalmente en troncos y rocas caídas. El uso de la vegetación puede representar una estrategia para obtener alimento y asimismo estar en un sitio seguro contra depredadores. A pesar de esto, la adaptabilidad que presenta la especie le provee la facilidad de usar muchos microhábitats en sitios donde la vegetación es escaza. Aunque el periodo de estudio fue corto, este estudio arroja las primeras observaciones acerca del uso del hábitat de esta especie en Costa Rica, información base para futuras investigaciones.

Se reporta la distribución de Centruroides edwardsii (Gervais, 1843) para el departamento de Antioquia, y el área urbana de su capital político-administrativa, la ciudad de Medellín, Colombia, con base a material depositado en la colección del Serpentario de la Universidad de Antioquia (SUA). Se estableció dimorfismo sexual en C. edwardsii, mediante análisis de escalamiento multidimensional y el modelo ANOSIM, encontrando que los machos son más grandes que las hembras. Se reporta para el área zona centro y nor-oriental de Medellín una importante colonia de este escorpión, hecho de gran relevancia debido a la importancia clínica de este escorpión. Se amplía además el rango de distribución desde el nivel del mar hasta los 2200 m s.n.m.

We report the distribution of the Centruroides edwardsii (Gervais, 1843) in the Antioquia province, and the urban area of the capital, Medellín, Colombia, based in the material examined in the collection of the Universidad de Antioquia Serpentarium (SUA). A sexual dimporphism were established in C. edwardsii when a multidimensional analysis and using for the statistical significance the ANOSIM model were performed founding higher sizes in males. An important colony of this scorpion is reported in the central and nor-oriental zone of Medellín, aspect that is very relevant since this scorpion is considered clinically relevante. The species distribution rank is also expanded from the sea level, up to 2200 m a.s.l.

In the present contribution, we redescribe the scorpion species Centruroides noxiusHoffmann, 1932, highly toxic and endemic to western Mexico (state of Nayarit). Its diagnosis is updated according to the modern standards for the genus, and enhanced with a photographic complement that depicts its main diagnostic characters. A new closely related species is also described from the same state, and some comments on the taxonomy and distribution of both taxa are given.

En la presente contribución, se redescribe Centruroides noxiusHoffmann, 1932, especie de alacrán altamente tóxica y endémica de México occidental (estado de Nayarit). Se actualiza su diagnóstico de acuerdo con los estándares actuales para el género y se mejora con un exhaustivo complemento fotográfico que permite apreciar sus principales caracteres diagnósticos. También se describe una especie nueva estrechamente relacionada que habita en este mismo estado y se hacen algunos comentarios sobre la taxonomía y distribución de ambas especies.

Ecuador harbors one of the most diverse Neotropical scorpion faunas, hereby updated to 47 species contained within eight genera and five families, which inhabits the “Costa” (n= 17), “Sierra” (n= 34), “Oriente” (n= 16) and “Insular” (n= 2) biogeographical regions, corresponding to the western coastal, Andean, Amazonian, and the Galápagos archipelago regions, respectively. The genusTityus Koch, in the family Buthidae, responsible for severe/fatal accidents elsewhere in northern South America and the Amazonia, is represented in Ecuador by 16 species, including T. asthenes, which has caused fatalities in Colombia and Panama, and now in the Ecuadorian provinces of Morona Santiago and Sucumbíos. Underestimation of the medical significance of scorpion envenoming in Ecuador arises from the fact thatCentruroides margaritatus (Gervais) (family Buthidae) andTeuthraustes atramentarius Simon (family Chactidae), whose venoms show low toxicity towards vertebrates, frequently envenom humans in the highly populated Guayas and Pichincha provinces. This work also updates the local scorpion faunal endemicity (74.5 %) and its geographical distribution, and reviews available medical/biochemical information on each species in the light of the increasing problem of scorpionism in the country. A proposal is hereby put forward to classify the Ecuadorian scorpions based on their potential medical importance.

Centruroides villegasi sp. nov. from the municipality of Chilapa de Álvarez, Guerrero, Mexico is described. It is the nineth species of Centruroides reported for this state. The new species is compared with C. limpidus (Karsch, 1879) which is morphologically similar and inhabits the same geographic zone. The species C. balsasensis Ponce and Francke, 2004, C. meisei Hoffmann, 1938, and C. tecomanus Hoffmann, 1932 are also compared because they are found in Guerrero and belong to the "striped scorpions" group (sensu Hoffmann, 1932), and therefore they are morphologically similar to the new species. It is a species of medical importance that had not been collected or recognized previously. A list of species of scorpions recorded for the state of Guerrero is included after the revision and correction of historical records.

Se describe Centruroides villegasi sp. nov. del municipio de Chilapa de Álvarez, Guerrero, que es la novena especie de Centruroides registrada para el estado. Se compara con C. limpidus (Karsch, 1879) por su parecido morfológico y por habitar la misma zona geográfica. Se compara también con C. balsasensis Ponce y Francke, 2004, C. meisei Hoffmann, 1938 y C. tecomanus Hoffmann, 1932, por pertenecer al grupo "alacranes rayados" (sensu Hoffmann, 1932), por su parecido morfológico y por su registro en Guerrero. Es una especie de importancia médica que no se había recolectado o reconocido previamente. Se incluye una lista de las especies de alacranes reconocidas para Guerrero, después de actualizar datos y hacer las correcciones necesarias a los registros históricos para el estado.