Influence of seasonality on habitat use and spatial distribution patterns of the buthid Physoctonus debilis in Brazil

 

The chose of habitat is important for scorpions for protection against predators and climate variations and for optimal access to prey. In some areas, climate seasonality has a strong effect on vegetation, and this may have an impact on the habitats chosen by scorpions.

André O. Silva-Júnior and co-workers have recently published a study on habitat use and spatial distribution patterns in a population of the tree-dwelling scorpion Physoctonus debilis (C. L. Koch, 1840) (Buthidae) across different seasonal periods in a Caatinga environment in Brazil.

The study demonstrates that the spatial distribution and habitat use of the tree-dwelling scorpion P. debilis are significantly influenced by seasonal changes, with variations observed among different sexes and developmental stages.

Abstract:
Habitat selection plays a crucial role in the survival of various animals, primarily due to their ability to identify suitable sites for development. In Caatinga regions, climate seasonality has a strong effect on vegetation, consequently influencing the occurrence and spatial distribution of diverse plant-associated organisms. The aim of this study was to analyse habitat use and spatial distribution patterns in a population of the tree-dwelling scorpion Physoctonus debilis (C. L. Koch, 1840) across different seasonal
periods in a Caatinga environment. Sampling was conducted during both dry and rainy seasons, each lasting 3 months, in northeastern Brazil. During each expedition, six plots measuring 30m× 30m and spaced 20m apart were sampled. In addition, the geographic coordinates of each specimen were recorded, and environmental metrics related to tree connectivity and isolation were measured. The results indicate that the population of P. debilis showed a higher occurrence during the dry season (158 individuals) than during the rainy season (105 individuals), with variations according to sex and developmental stage. Female occurrence was more frequently during the dry season, whereas immatures showed a higher occurrence during the rainy season. Our results also revealed spatial aggregation at short distances, with the intensity of aggregation varying among sexes, developmental stages, tree connectivity and climatic seasons. Overall, these results indicate that the spatial distribution of P. debilis is distance-dependent, with stronger spatial aggregation occurring at shorter distances.

Reference:
Silva-Júnior AO, Celante GL, Foerster SÍA, Feitosa MLB, Moura GJB, Lira AFA. Influence of Seasonality on Habitat use and Spatial Distribution Patterns of Tree-Dwelling Scorpion (Physoctonus debilis) in Brazilian Caatinga. New Zealand J Zool. 2026;53(3). [Open Access]

New locality records and potential distribution in the future of Sassanidotus gracilis in the Iran–Afghanistan–Pakistan arid belt

 

 Ersen Yagmur and co-workers have recently published an article with new new locality records for Sassanidotus gracilis (Birula, 1900) (Buthidae) in Iran. There is very little information about the potential distribution of this species in Iran and neighboring countries. The author present a potential distribution of this species in the Iran–Afghanistan–Pakistan arid belt based on analysis of the future habitat suitability for this species.

Abstract:
This study reports new locality records from Iran and a climate-based habitat suitability assessment for Sassanidotus gracilis (Birula, 1900) (Scorpiones: Buthidae) in the Iran–Afghanistan–Pakistan arid belt. We document new specimens from Sistan and Baluchestan Province, Iran, with an updated distribution map and illustrations, and we model the species’ potential distribution across south-eastern Iran and adjacent parts of Afghanistan and Pakistan.

Habitat suitability was associated mainly with precipitation seasonality, precipitation of the wettest month, precipitation of the driest month, and slope. In an arid setting these rainfall variables are unlikely to indicate a need for moist habitat; they more plausibly track seasonal productivity and the terrain features that provide shelter. Present-day suitable areas were concentrated in south-eastern Iran, particularly Sistan and Baluchestan, and extended into south-western Afghanistan and western Pakistan.
Projections under SSP1-2.6, SSP3-7.0 and SSP5-8.5 indicated that suitable habitat persists across most core areas but is redistributed over time. Net change was small and negative under every scenario, from about −0.4% to −7.0% of the present suitable area, with the largest reduction under SSP5-8.5 for 2071–2100. These net values were accompanied by high spatial turnover: even in the near-future period about 44% of the present suitable area was reclassified as unsuitable while a comparable area became newly suitable. Disagreement among climate models was large and grew with time and emission level (mean coefficient of variation 28–75%), so the net changes are of similar or smaller magnitude than the projection uncertainty and should be read as evidence of spatial reorganization rather than precise area loss.

The species therefore seems likely to keep much of its suitable habitat, although the high-emission scenario points to more fragmentation late in the century. Because a dispersal-limited scorpion may have limited ability to rapidly reach newly suitable areas, the predicted areas are best treated as hypotheses for survey rather than forecasts of occupancy. They identify priority targets in poorly sampled parts of south-eastern Iran, western Pakistan and adjacent Afghanistan.

Reference:
Yağmur EA, Çiçek K, Barati H, Moradi M. New locality records and future habitat suitability of Sassanidotus gracilis (Birula, 1900)(Scorpiones: Buthidae) in the Iran–Afghanistan–Pakistan arid belt. Euscorpius. 2026(440):1–19. [Open Access]

Trends in species richness and abundance in Central Algerian Sahara during a 10 year period

 

Getting data on changes in biodiversity of scorpions and other arthropods in a region over time is important. These data can be related to factors like climate and human impact. Salah Eddine Sadine and co-workers have recently published a study of the trends in scorpion richness, abundance and community structure in Central Algerian Sahara during 10 years.

Interestingly, the scorpion richness increased significantly during the observation period. The authors do not believe that this is a result of increased biodiversity, but rather reflects the increased and improved taxonomical research in the last decades that has revealed several new, but already existing taxa. 

Total abundance showed strong variability between the years in the study period, but without a clear temporal trend. The authors concludes that this may indicate  indicating a decoupling between richness and overall population size. See abstract and article for more information and details.

Abstract:
Understanding long-term temporal dynamics of desert arthropod communities is essential for evaluating ecosystem responses to environmental variability. This study investigates decadal changes (2014–2024) in species richness, abundance, diversity, and assemblage composition of scorpions in the central Algerian Sahara. Annual species abundance data were analyzed using diversity indices and multivariate approaches. Temporal turnover in species composition was assessed using Bray–Curtis dissimilarity, linear regression, and SIMPER analysis to identify species contributing to assemblage change. Species richness increased substantially over the study period, rising from four species in 2014 to eleven species in 2024, but this rise likely reflects improved taxonomic knowledge and more complete inventories rather than a recent ecological colonization. In contrast, total abundance showed strong interannual variability without a clear temporal trend, indicating a decoupling between richness and overall population size. Diversity indices increased progressively, with higher Shannon and Simpson values in later years, reflecting reduced dominance and greater evenness, although both indices reached minimum values in 2019. Temporal β-diversity revealed moderate interannual turnover (mean dissimilarity = 0.22) and a non-significant decline through time, suggesting gradual assemblage reorganization. SIMPER analysis indicated that temporal change was mainly driven by shifts in dominance, particularly the decline of Androctonus amoreuxi and changes in secondary species such as Buthacus samiae and Lissothus chaambi. Overall, scorpion assemblages exhibited increasing richness and diversity with moderate turnover, driven primarily by changes in species dominance rather than widespread species replacement.

Reference:
Sadine SE, Zebsa R, Bensakhri Z, Souilem Z, Rouari L, Houhamdi M, et al. A Decade of Change: Trends in Scorpion Richness, Abundance, and Community Structure in Central Algerian Sahara. Diversity. 2026;18(7). [Open Access]

Thanks to André for informing me about their study.  

A study of the defensive behaviour of the buthid scorpion Buthus atlantis

 

The scorpions' sting and venom use is important in both prey capture and defense. Several studies have previously investigated sting use in defense and also the use of venom (dry versus wet stings and the discovery of prevenom). 

Youssef El Joud and co-workers have recently published a study analyzing how various factors such as temperature, prey type, and threatening conditions influence stinging behaviour, venom usage and regeneration in the scorpion Buthus atlantis Pocock, 1889 (Buthidae) from Morocco.

Their study shows that the scorpions are more ready to sting in defense in higher temperatures and that venom expenditure in B. atlantis is regulated by both temperature and threatening conditions.

Abstract:
Understanding animal’s behaviour and adaptation in the face of threats and predators under different biotic and abiotic conditions is fundamental in ecology. In this study we examined defensive behaviour of Buthus atlantis scorpion in order to assess how various factors such as temperature, prey type, and threatening conditions influence stinging behaviour, venom usage and regeneration. Our study had revealed that stings frequency was significantly lower in cooler temperature compared to the medium and warm temperature. Threatening condition had no significant effect in medium and warmer temperature, the difference between the two conditions was only significant in the cooler temperature. Conversely, we had shown that venom expenditure in B. atlantis is regulated by both temperature and threatening conditions. Our results show that scorpions maintained in higher temperatures yielded the greatest amount of venom compared to those in lower temperatures. Analyses of proteins concentration according to temperature and diet variation had revealed that scorpions placed in intermediate (25 ◦C) and warmer temperature (40 ◦C) had a significantly higher venom proteins concentration when compared to the cooler temperature (10 ◦C). Results also showed that scorpions adjust their venom usage based on their perception of danger, which can be influenced by temperature.

Reference:
El Joud Y, El Bouazzaoui A, El-Ghali S, Laghzaoui EM, Toulon O, Ait Larradia M, et al. Assessing the effects of temperature, diet and threat conditions on defensive behaviour and venom regeneration in scorpion (Buthus atlantis). J Therm Biol. 2024;124:103966. [Subscription required for full text]

The diversity patterns of Egyptian scorpions in relation to climatic and spatial predictors

 

Understanding the biological diversity of scorpions in different habitats is important. Andre Lira and co-workers have recently published an article trying to evaluate the diversity patterns of Egyptian scorpions in relation to climatic and spatial predictors. See abstract below to learn more about the study and its results.

Abstract:
Drylands correspond to ca. 40% of the world’s land surface. Because of their ecological importance, these areas are regularly considered for agricultural purposes. Scorpion assemblages often exhibit higher levels of species diversity in dry habitats and are beneficial indicators in ecological studies in such environments. In this study, we investigated the effects of climatic and spatial predictors on beta diversity patterns among scorpion assemblages distributed in the drylands of Egypt. Scorpion occurrences were compiled from the scientific literature. For each location, we created a set of climatic variables related to precipitation, temperature, and solar irradiation, as well as spatial predictors. A total of 134 scorpion occurrences were obtained, comprising 21 species grouped into three families. Climatic and spatial variables together influenced the patterns of scorpion diversity in Egyptian landscapes. Species replacement accounted for 69% of the total beta diversity. In addition, species replacement was positively affected by climatic and spatial variables. Our results suggest a reciprocal link between the region’s ecological history and the patterns of beta diversity observed in scorpion assemblages from Egyptian drylands.

Reference:
Lira AF, Foerster SÍ, Badry A. Living in a desert: examining scorpion beta diversity in Egyptian drylands from a macroecological perspective. African Zoology. 2023:1-11. [Subscription required for full text]

Thanks to Andre for sending me their article!

Paruroctonus marksi is most active when it is warm and humid

 

Scorpion surface activity is influenced by several factors, both biotic (e.g. prey or mate availability or predator risk) and abiotic (e.g. weather or illumation). Zia Nisani and co--workers have recently published a study on seasonal variations of Paruroctonus marksi Haradon, 1984 (Vaejovidae) activity in the Mojave Desert in California, US.

Their main finding was that the scorpions were mostly active in warm and humid nights, but that soil temperature also seemed to have a small impact on the activity.

Abstract:
Many environmental factors may influence the activity pattern of scorpions in arid ecosystems. We investigated the seasonal variations of Paruroctonus marksi scorpion activity in the Mojave Desert (California, USA). Black light surveys were carried out within two 100 ×100 m plots from August 2017 to September 2018. The majority (85%) of scorpions were found in open areas compared with being in vegetation. The presence of P. marksi was positively correlated with both water vapor pressure and soil temperature, while moon illumination had no significant effect on P. marksi foraging behavior. Scorpions might be using humidity as an indicator of prey abundance and since they are not visual hunters, and moonlight does not affect their surface activity possibly due to lack of visual hunters in the study site.

Reference:
Nisani Z, Frederick D, Garcia-Plascencia A, Lopez D, Miller R, Trinh-Nguyen L. Influence of environmental factors on surface activity of Paruroctonus marksi (Scorpiones: Vaejovidae) in the Mojave Desert. Euscorpius. 2022(364):1-5. [Open Access]

Relationship between scorpion sting events and environmental conditions in mainland France

 

Jules-Antoine Vaucel and co-workers have published a thorough study of scorpion stings in mainland France. This is interesting in itself and I find it especially interesting that they report of one event of scorpion sting involving the enigmatic B. xambeui Simon, 1879 (Belisaiidae). Unfortunately, they present no details on this incident, but I guess it caused no serious morbidity. Other species represented in the study were Buthus occitanus (Amoreux, 1789) (Buthidae) and Euscorpius concinnus (Koch, 1837), Euscorpius italicus (Herbst, 1800), Euscorpius tergestinus (Koch, 1837), and Tetratrichobothrius flavicaudis (De Geer, 1778) (all in the family Euscorpiidae).

As the title indicate, the authors have tried to find a relationship relationship between scorpion sting events and environmental conditions like level of sunshine, temperature etc. The authors conclude that climatic variations could well predict encounters between humans and scorpions in France. 

Abstract:
In the world, the impact of environmental conditions on the number of scorpion events was evaluated in North Africa,Middle East, and the Amazonian region but not in Europe. In mainland France, scorpion species described are Buthus occitanus (Amoreux, 1789), Belisarius xambeui (Simon, 1879) and 4 Euscorpiidae: Euscorpius concinnus (Koch, 1837), Euscorpius italicus (Herbst, 1800), Euscorpius tergestinus (Koch, 1837), and Tetratrichobothrius flavicaudis (De Geer, 1778). We aimed to describe the impact of environmental conduction on the number of scorpion events. For this, a retrospective multi-center study was conducted with data from the French poison control centers files about scorpion events between 1 January 2011 and 31 December 2020. During the study period, 975 incoming calls for scorpion events were recorded and 574 were related to scorpions native to mainland France and Corsica: B. occitanus (n = 86), Euscorpiidae species (n = 222), B. xambeui (n = 1), and undetermined species (n = 265). Cases were mostly reported along the Mediterranean coast, along rivers, and in cities with a trading port. The number of scorpion events was linked to the rivers' water level, rivers' flow, temperature, sunshine, and pluviometry (P < 0.05 for all variables). B. occitanus need warmest and driest environment than Euscorpiidae spp. A link between the severity of the envenoming and climatic condition or seasonality was not demonstrated.

Reference:
Vaucel JA, Larreche S, Paradis C, Labadie M, Courtois A, Grenet G, et al. Relationship Between Scorpion Stings Events and Environmental Conditions in Mainland France. J Med Entomol. 2021. [Subscription required for full text]

Does climate have an impact on body size in scorpions?

 

Scorpions vary in size, both within and between species. This variation may have different causes. Some studies have shown that body size may have been affected by a range of climatic conditions along species ranges, especially when they are distributed across climatic gradients

Andre Lira and co-workers have studied the responses of scorpion body size at different organizational
levels (inter and intraspecific) along a dry-wet climatic gradient in Brazilian forests. Their study provides the first ecological assessment in South America, devoted to the understanding of how body size in scorpions can be modulated by climatic features at both inter- and intraspecific levels. I refer to the abstract or the article for more details on the results.

Abstract:
Body size is believed to be one of the most fundamental functional traits in animals and is evolutionarily conserved in order to guarantee the survival of the species. Besides the phylogenetic backgrounds, body size patterns might be a product of environmental filters, especially within fine taxonomic levels (i.e., within species or geographical lineages). Here, we evaluated the responses of scorpion body size at different organizational levels (inter and intraspecific) along a dry-wet climatic gradient in Brazilian forests. Scorpions were collected from 20 localities in northeastern Brazil, covering 12 sites of dry forests and eight sites in rainforest environments. As a proxy for body size, we measured the carapace length of 368 adult scorpions belonging to 11 species and applied linear mixed-effects models to investigate the potential effects of climatic features and geographical tendencies in this trait at inter- and intraspecific levels. Our findings suggest the existence of a longitudinal pattern of body size in scorpions with species becoming larger in an east-west direction (i.e., towards the continent); such geographical tendency was also detected for one of the three species analyzed at the population level. In addition, the warmer temperature had a negative effect on body size in scorpions at inter- and intraspecific levels. Based on these findings, we assert that body size in scorpions is not affected solely by their phylogenetic history, but also by the physiological constraints imposed by the environment, which becomes more evident across climatic gradients.

Reference:
Lira AFA, Foerster SIA, Albuquerque CMR, Moura GJB. Contrasting patterns at interspecific and intraspecific levels in scorpion body size across a climatic gradient from rainforest to dryland vegetation. Zoology (Jena). 2021;146:125908. [Subscription required for full text]

Thanks to Andre and Stenio for sending me their articles!

Distribution and habitat characteristics of two scorpion species in Miyako Islands, Japan

 

 Kawai Kazusa has recently published the results of a scorpion survey conducted in five Japanese islands. Two species, Liocheles australasiae (Fabricius, 1775) (Hormuridae) and Isometrus maculatus (DeGeer, 1778) (Buthidae) were found. Data on distribution, habitat and climate are presented. 

Abstract:
Scorpion surveys were conducted in the five islands: Miyakojima, Ikemajima, Kurimajima, Irabujima, and Shimojishima (Miyako Islands, part of Nansei/Ryukyu Islands of Japan). Eight individuals of Liocheles australasiae (Hormuridae) and 16 individuals of Isometrus maculatus (Buthidae) were observed in a total of 10 points on four islands, except Ikemajima. The localities of both species are recorded in this survey, focusing on altitude, distance from the nearest coast, and sunlight. The lowest temperatures in the habitat are also examined, and the cold tolerance of the species is discussed.

References:
Kawai K. Habitat characteristics of two scorpion species, Liocheles australasiae (Fabricius, 1775) and Isometrus maculatus (De Geer, 1778) in Miyako Islands, Japan. Euscorpius. 2021(331):1-17. [Open Access]

Thanks to Kawai for informing me about his article!

How will climate changes impact the diverse scorpion fauna of Mexico?

Scorpions are infamous among many peoples and many will not focus on the conservation of this "dangerous" animal group when the global climate changes. But it is important to remember that scorpion diversity is an indicator of the health of the fauna in an area or its ecosystem and knowledge about the impact of climate changes on the scorpion fauna is important for more than scorpions alone.

Carolina Ureta and co-workers have recently published a study evaluating the vulnerability of scorpions in Mexico to climate change and if Mexican protective measures are sufficient to protect this animal group under future climate models. The short answer is that the scorpion fauna of Mexico is vulnerable under both current and under future climatic conditions.

Abstract:
Scorpions have high levels of endemism and their distributions are typically narrow, making them particularly vulnerable to changes in their environment. Unfortunately, little is known about the status ofscorpion conservation worldwide. Here, we compiled information on scorpion diversity across the world and highlighted Mexican scorpion diversity. We created and overlapped scorpions’ hotspots with the Mexican system of protected areas. We also modeled the potential distribution area of 24 wide distributed scorpion species under current and future scenarios to evaluate their vulnerability to climate change considering full and null dispersal models, and calculated the percentage of their distribution that will be protected by the natural protected areas in the future. Our results indicate that while Mexico has the greatest diversity of scorpion species compared to any other country in the world, these animals are not sufficiently protected by the system of natural protected areas under neither current nor under future climatic conditions. In terms of climate change vulnerability, we assessed the impact to these species if their migration to future more climatically suitable areas is not feasible. However, if full migration is feasible for species with broad ecological habitats, nine species might have a more widespread distribution,including three species with medical importance (Centruroides spp.).

Reference:
Ureta C, González EJ, Ramírez-Barrón M, Contreras-Félix GA, Santibáñez-López CE. Climate change will have an important impact on scorpion’s fauna in its most diverse country, Mexico. Perspectives in Ecology and Conservation. 2020;18(2):116-23. [Open Access]

Thanks to Matt Simon for informing me about this article!

 

The potential impact of climate change on the future distribution of scorpion species in two different ecosystems in Brazil

Climate changes and subsequent habitat changes or destruction is high on the agenda these days. But how will climate change impact on scorpions? Andre Lira and co-workers published a study in December trying to answer this question.

And not surprisingly their study showed that all 10 species in the study presented a drastic reduction in potential distribution du to expected climate changes, ranging from 44% to 72%, when compared with their current distribution. Interestingly, this applied both to generalist and specialist species. It was expected that latter was more vulnerable to changes than the former.

Abstract:
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.

Reference:
Lira AFDA, Badillo-Montaño R, Lira-Noriega A, de Albuquerque CMR. Potential distribution patterns of scorpions in north-eastern Brazil under scenarios of future climate change. Austral Ecol. 2019. [Subscription required for full text]

Thanks to Andre Lira for sending me their article!

Scorpions as environmental indicators

Andre Lira and co-workers have recently publised a study looking into how scorpion diversity, species richness, and species composition respond to bioclimatic changes (like forests with different gradients of humidity).

The study indicated that much of the scorpion composition and diversity in the study area were explained by a longitudinal bioclimatic gradient (wet-dry forest) and that species richness increased with increasingly dry conditions along the longitudinal gradient. Based on the results presented in this study, the authors belive that scorpions can be used as environmental indicators due to the high detectability, sensitivity to environmental attributes, and well known and stable taxonomy.

Abstract:
Understanding large-scale patterns of biological diversity is one of the most important issues in ecology. Parameters of scorpion assemblages may serve as a proxy to understand how arthropods respond to bioclimatic changes by adjusting their spatially structured distribution. We analysed how scorpion species richness, abundance, and composition respond to climatic variations found along a longitudinal gradient between wet (Atlantic Forest) and dry (Caatinga hypo and hyperxerophilic) forests in Brazil. A total of 20 sites were sampled four times along a 712 km longitudinal wet-dry bioclimatic gradient in north-eastern Brazil. We recorded 2653 scorpions from 12 species, belonging to five genera and two families. Environmental variables associated with precipitation and temperature had a strong effect on scorpion distribution, resulting in a distinct faunal composition at both extremes of the gradient. Species composition presented a turnover along the bioclimatic gradient, with beta diversity increasing towards the drier sites. The increase of dryness coincide with increases in temperature, moisture reduction, and a general environmental harshness. Our study, therefore, indicates that species sensitivity to climatic variation determines scorpion distribution in Neotropical forests.

Reference:
Lira AFA, Salomão RP, Albuquerque CMR. Pattern of scorpion diversity across a bioclimatic dry-wet gradient in Neotropical forests. Acta Oecologica. 2019;96:10-7. [Subscription required for full text]

Thanks to Andre Lira for sending me their study!