Bothrops Atrox Research Articles

Sexual dimorphism and ontogenetic variation in the head shape of two neighbouring populations of the common lancehead Bothrops jararaca (Serpentes: Viperidae)

Abstract The head is the most important element in trophic ecology among snakes. Head shape is affected by several factors, both intrinsic, such as size and sex, and extrinsic, such as geographical variation. Often, different populations are subject to different environmental conditions that are reflected in different phenotypes adapted to local conditions. Here, we investigate sexual dimorphism, ontogenetic allometry and environmental effects on head shape in two populations of Bothrops jararaca. We have found a significant effect of sex and population, with females from the highland population having a large braincase region and a more arrow-shaped head. Size increase accounted for a considerable amount of variation in shape, but the coefficient of correlation diverged between populations. Sexual dimorphism in head shape was not found in juveniles, but the ontogenetic trajectory was non-parallel between populations. Rainfall was most associated with a larger snout and reduced braincase. In the genus Bothrops, except in early stages, females often grow faster and attain larger sizes than males, which might affect head shape. Also, possible differences in diet, behaviour and ontogenetic variations between populations might be a reasonable cause of specific allometric trajectories.

Bothrops atrox venom: Biochemical properties and cellular phenotypes of three highly toxic classes of toxins

Snake venoms have a complex mixture of compounds that are conserved across species and act synergistically, triggering severe local and systemic effects. Identification of the toxin classes that are most damaging to cell homeostasis would be a powerful approach to focus on the main activities that underpin envenomation. Here, we focus on the venom of Bothrops atrox, snake responsible for most of the accidents in Amazon region of South America. We identified the key cytotoxic toxin fractions from B. atrox venom and mapped their biochemical properties, protein composition and cell damage. Five fractions were obtained by mass exclusion chromatography and contained either a single class of enzymatic activity (i.e., L-amino acid oxidases or Hyaluronidases) or different activities co-distributed in two or more protein fractions (e.g., Metalloproteinases, Serine Proteases, or Phospholipases A2). Only three protein fractions reduced cell viability of primary human cells. Strikingly, such activity is accompanied by disruption of cell attachment to substratum and to neighbouring cells. Such strong perturbation of morphological cell features indicates likely defects in tissue integrity in vivo. Mass spectrometry identified the main classes of toxins that contribute to these phenotypes. We provide here a strategy for the selection of key cytotoxic proteins for targeted investigation of their mechanism of action and potential synergism during snakebite envenomation. Our data highlights putative toxins (or combinations of) that may be the focus of future therapeutic interference.

The Potential of Snake Venoms as Coagulation Agent for Hemorrhagic Trauma: A Review

Snake venom contains a variety of proteins and enzymes that can affect blood coagulation and have been investigated for their potential use as hemostatic agents to stop hemorrhage. Hemorrhage can be caused by a variety of factors, including injury, surgery, and certain medical conditions, and can be life-threatening if not controlled. Several components of snake venom have been identified as potential hemostatic agents. One such component is Batroxobin, a metalloproteinase found in the venom of the Bothrops atrox snake. Batroxobin has been shown to activate prothrombin to thrombin, which promotes clot formation and can be used to stop bleeding. Ancrod is a serine protease that can cleave fibrinogen, reducing the concentration of fibrinogen in the blood and preventing clot formation. Ancrod has been used as a hemostatic agent in the past, but its use has been limited due to concerns about its safety and efficacy. Other components of snake venom, such as those found in the venom of Russell's viper and the saw-scaled viper, have been found to have potential as hemostatic agents. These components have been shown to activate factor X and have been investigated as potential treatments for hemorrhage. The use of snake venom as a hemostatic agent is not without its challenges. One of the main concerns is the potential for adverse reactions, including allergic reactions, and the risk of complications such as thrombosis. Additionally, the availability of snake venom is limited, and the production of synthetic versions of these compounds can be challenging. Despite these challenges, the potential of snake venom as a hemostatic agent is promising, particularly in the development of new, more targeted treatments for hemorrhage. Further research is needed to fully understand the mechanisms of action of snake venom-derived hemostatic agents and to develop safe and effective therapeutic agents. In conclusion, snake venom contains a variety of components that have the potential as hemostatic agents to stop hemorrhage. While the use of snake venom-derived hemostatic agents is not without its challenges, these agents have promising potential in the treatment of a range of medical conditions. Keywords: Snake venom, coagulation agent, hemorrhagic trauma

Antibiotic susceptibility of cultivable microbiota from the oral cavity of captive Bothrops atrox and Bothrops lanceolatus: Implications for the treatment of snakebite-associated infections in the French departments of America

IntroductionSecondary infection is a frequent complication after bites by Bothrops atroxin French Guiana or B. lanceolatus in Martinique. Knowledge of the bacteria present in snake mouths is a valuable aid for determining probabilistic antibiotherapy after Bothrops bite. The objectives of this study were to describe the cultivable bacteria of the oral microbiota of the specimens of B. atrox and B. lanceolatus kept in captivity, and to study their susceptibility to antibiotics. MethodsFifteen B. atrox and 15 B. lanceolatus were sampled. Bacterial cultures were performed and each morphotype on plates was identified using MALDI-TOF mass spectrometry. Antibiotic susceptibility was studied using the agar disk diffusion method, with possible determination of the MICs. ResultsOne hundred and twenty-two isolates were identified: 52 isolates and 13 species in B. atrox, 70 isolates and 23 species in B. lanceolatus. The main species were Providencia rettgeri, Morganella morganii, Pseudomonas aeruginosa, Staphylococcus xylosus, and Paeniclostridium sordellii (only in B. lanceolatus mouths). For B. atrox, 96% of isolates were susceptible to piperacillin/tazobactam, cefepime, imipenem and meropenem, 94% to ciprofloxacin and 76% to cefotaxime and ceftriaxone. For B. lanceolatus, 97% of isolates were susceptible to meropenem, 96% to cefepime, 93% to imipenem and piperacillin/tazobactam, 80% to ciprofloxacin, and 75% to cefotaxime and ceftriaxone. Many isolates were resistant towards amoxicillin/clavulanate. ConclusionAmong currently recommended antibiotics, cefepime and piperacillin/tazobactam seem more suitable than cefotaxime or ceftriaxone in the event of a Bothrops bite. Ciprofloxacin may also be considered for B. atrox.

Efficacy of low-level laser therapy in reducing local manifestations of bothrops atrox envenomations: a randomized clinical trial

Efficacy of low-level laser therapy in reducing local manifestations of bothrops atrox envenomations: a randomized clinical trial

Individual variation in venom from the left and right glands of snakes of the species Bothrops atrox

Individual variation in venom from the left and right glands of snakes of the species Bothrops atrox

Exploring the Profile of Cell Populations and Soluble Immunological Mediators in Bothrops atrox Envenomations.

Bothrops atrox envenomations are common in the Brazilian Amazon. The venom of B. atrox is highly inflammatory, which results in severe local complications, including the formation of blisters. Moreover, there is little information on the immune mechanisms associated with this condition. Thus, a longitudinal study was carried out to characterize the profile of the cell populations and soluble immunological mediators in the peripheral blood and blisters in B. atrox patients s according to their clinical manifestations (mild and severe). A similar response in both B. atrox patient groups (MILD and SEV) was observed, with an increase in inflammatory monocytes, NKT, and T and B cells, as well as CCL2, CCL5, CXCL9, CXCL10, IL-1β and IL-10, when compared with the group of healthy blood donors. After the administration of antivenom, the participation of patrolling monocytes and IL-10 in the MILD group was observed. In the SEV group, the participation of B cells was observed, with high levels of CCL2 and IL-6. In the blister exudate, a hyperinflammatory profile was observed. In conclusion, we revealed the involvement of cell populations and soluble mediators in the immune response to B. atrox envenomation at the local and peripheral level, which is related to the onset and extent of the inflammation/clinical manifestation.

Bothrops (Fer-de-lance) snakebites in the French departments of the Americas (Martinique and Guyana): Clinical and experimental studies and treatment by immunotherapy.

Snakebite envenomation is a relevant medical hazard in French Guiana and Martinique, two French territories in the Americas. All snakebite envenomations in Martinique are inflicted by the endemic viperid species Bothrops lanceolatus, whereas Bothrops atrox is responsible for the majority of snakebites in French Guiana, although other venomous snake species also occur in this South American territory. This review summarizes some of the key aspects of the natural history of these species, as well as of their venom composition, the main clinical manifestations of envenomations, and their treatment by antivenoms. B. atrox venom induces the typical set of clinical manifestations characteristic of Bothrops sp. venoms, i.e., local tissue damage and systemic alterations associated with coagulopathies, hemorrhage, hemodynamic alterations, and acute kidney injury. In the case of B. lanceolatus venom, in addition to some typical features of bothropic envenomation, a unique and severe thrombotic effect occurs in some patients. The pathogenesis of this effect remains unknown but may be related to the action of venom components and inflammatory mediators on endothelial cells in the vasculature. A monospecific antivenom has been successfully used in Martinique to treat envenomations by B. lanceolatus. In the case of French Guiana, a polyvalent antivenom has been used for some years, but it is necessary to assess the preclinical and clinical efficacy against viperid venoms in this country of other antivenoms manufactured in the Americas.

Isolation and characterization of the first phosphodiesterase (Bj-PDE) from the venom of Bothrops jararacussu snake

Phosphodiesterases are exonucleases that sequentially hydrolyse phosphodiester bonds of polynucleotides from the 3′-end and release 5-mononucleotides. After more than one decade without any advance in the study of Bothropic phosphodiesterases, we described here the isolation of the first phosphodiesterase from Bothrops jararacussu, which we named Bj-PDE. A five-step column chromatography procedure (size exclusion, hydrophobic interaction, cation exchange, lentil lectin affinity, and blue sepharose affinity) enabled isolation of Bj-PDE with preserved and stable enzymatic activity (bis(p-nitrophenyl) phosphate substrate), Km = 6.9 mM (± 0.7 mM), kcat/Km = 1.7 × 104 M−1 s−1 (± 0.2 × 104 M−1 s−1), MW = 116 kDa (SDS-PAGE), optimum activity around 45 °C at pH 8.0, and stability for 81 days at different storage temperatures (8, −20, and − 80 °C). Ca2+ and Mg2+ ions positively influenced Bj-PDE activity, while EDTA had the opposite action. Zn2+ restored >50 % of enzyme activity after its inhibition by EDTA. The Bj-PDE partial sequence identified by mass spectrometry was very similar to the sequence of BATXPDE1 from Bothrops atrox, which was evolutionarily close to this new PDE. Therefore, our study represents an important progress on the isolation of this minor toxin and sheds new lights on the properties and bioprospection of bothropic phosphodiesterases.

Batroxin I: A Novel Bradykinin-Potentiating Peptide with Cytotoxic Activity Isolated from Bothrops atrox Snake Venom

Venom peptides are interesting molecular models for the development of biotechnological strategies applicable in generating therapeutic agents and/or experimental tools for basic and applied research. The present study aimed to search for peptides from Bothrops atrox snake venom with anticancer potential activity against HepG2 liver tumor cell line, determine their cytotoxic action, and analyze the structure–function relationship. The novel peptide Batroxin I (M.W. 1.38 kDa) was isolated by molecular exclusion and reversed phase chromatography methods. The Batroxin I presented a selective cytotoxicity towards tumor cells, reducing the viability of HepG2 cells by 94.6% with IC50 of 0.72 μg/mL, and showing a low toxicity against peripheral blood mononuclear cells. Analysis of the apoptotic and necrotic peptide effects revealed that it induced apoptosis by intrinsic pathway activation. The amino acid sequence of Batroxin I was determined by de novo sequencing as < EKWPRPDAPIPP (where < E = pyroglutamic acid); hence, it is an unpublished peptide that belongs to the class of bradykinin-enhancing peptides and cell penetration peptide. This is one of the first reports on the cytotoxic antitumor activity of a bradykinin-enhancing peptide. Our results indicate that this peptide could serve not only as a template for the development of new drugs, but also as an adjuvant to less effective marketed drugs to treat cancer and other diseases.

Bothrops atrox mice experimental envenoming treatment using light-emitting diode (led) as an adjunct therapy to conventional serum therapy.

The use of anti-venom is one of the main control measures for snakebite envenoming when applied immediately after the snakebite. Systemic effects of the envenoming are usually reversed; however, neutralization of local effects is hardly achieved. The need for adjuvant therapies associated with serum therapy can improve the treatment for local effects of envenoming, with greater effectiveness in preventing or delaying the progression of damage, reducing the clinical signs and symptoms of victims of snakebites. The purpose of the study was to evaluate the photobiomodulation therapy using LED and/or dexamethasone associated with conventional serum therapy for the treatment of local damage caused by Bothrops atrox envenomation in a murine model. For this, experimental envenoming was carried out in the gastrocnemius muscle of male Swiss mice weighing 18 to 22g divided into 8 groups of animals, distributed in groups non-treat, treated with anti-bothropic serum, dexamethasone, and LED, or the associated treatments, by intramuscular inoculation of 50µg of venom or sterile PBS (control). After 30min, the proposed treatments were administered alone or in combination. After 3h, blood and muscle samples were collected for myotoxicity, cytotoxicity, histological analysis, and IL-1β assays. The evaluation of the treatment alone showed that serum therapy is not effective for the treatment of local damage and photobiomodulation demonstrated to be an effective therapy to reduce leukocyte infiltration, hemorrhage, and myotoxicity in experimental envenoming; dexamethasone proved to be a good resource for the treatment of the inflammatory process reducing the leukocyte infiltration. The association of serum therapy, LED, and dexamethasone was the best treatment to reduce the local effects caused by Bothrops atrox venom. All in all, the association of photobiomodulation therapy using LED with conventional serum therapy and the anti-inflammatory drug is the best treatment for reducing the undesirable local effects caused by snakebite accidents involving B. atrox species.

Simultaneous identification of three clinically relevant peruvian pit vipers by multiplex loop-mediated isothermal amplification (mLAMP)

Previous knowledge about the taxonomic distribution of venomous snake species is very useful for epidemiological aspects of ophidism. Here, we sought to develop an assay for the differential identification of clinically relevant snakes in Peru: Bothrops atrox, Lachesis muta, and Crotalus durissus using a multiplex loop-mediated isothermal amplification (mLAMP) assay. For this, DNA was extracted from the shed snake skins and the mitochondrial genes Cytb, COI, and 12S rRNA were amplified and further sequenced, for the design of mLAMP reaction primers. For each snake species the forward and reverse primers, internal forward and reverse primers, and the loop primers were obtained, bearing the latter different fluorophores for product identification. Finally, the reaction was standardized in the presence of all primer sets, and an optimal amount of low molecular weight polyethyleneimine. The precipitated products were observed in a UV light transilluminator, finding a differential fluorescence according to the DNA used, with a detection limit to the naked eye in the range of 0.2–25 ng of DNA, within 30 min. This study is the first report on the use of mLAMP technology for the identification of venomous snakes.

Composition and natural history of snakes from Zona da Mata in Rondonia, southwestern brazilian Amazon

This study presents an account on the snake assemblage and its natural history in the state of Rondônia. Data collection was carried out between January and December 2018. The surveys were done through time constrained searches, pitfall traps, and occasional encounters. A total of 155 snakes corresponding to 60 species were recorded, of which 12 species were registered for the first time in the Zona da Mata region, including new records for the state of Rondônia (Lygophis meridionalis and Atractus pantostictus). The most abundant species was the Common Lancehead (Bothrops atrox). Active snakes were most frequently observed on the ground (63.22%). Lizards were the nost frequent prey consumed by snakes (45% of species). Snake richness can still be considered underestimated, highlighting the need of new studies.

Hematologic parameters of captive Bothrops atrox (Squamata: viperidae)

The breeding of venomous snakes in captivity for research purposes and mainly as a source of pharmaceutical products highlights the need to determine hematological parameters for monitoring and ensuring a healthy breeding populationThe complete blood count is used to help diagnose alterations such as anemia, inflammatory diseases, parasitemia, hematopoietic disorders, hemostatic and toxicological changes, as well as bacterial and viral inclusions. Thus, the objective of this study was to define reference parameters for complete blood count in Bothrops atrox snakes. Blood samples were collected from 20 specimens of B. atrox from the Pentapharm do Brasil commercial breeding facility for laboratory examination. Mean values and standard deviation were: hematocrit 33.6 ± 5.47%, hemoglobin 10.81 ± 2.07g/dL, total number of erythrocytes 0.59 ± 0.1 x 106/mm3, leukocytes 11387.5 ± 3279.2/mm3 and thrombocytes 28175 ± 6320/mm3. No significant difference was observed between males and females and heterophils were the predominant leukocyte cell type.

Two-Dimensional Blue Native/SDS Polyacrylamide Gel Electrophoresis for Analysis of Brazilian Bothrops Snake Venoms.

Viperidae snakes are the most important agents of snakebites in Brazil. The protein composition of snake venoms has been frequently analyzed by means of electrophoretic techniques, but the interaction of proteins in venoms has barely been addressed. An electrophoretic technique that has gained prominence to study this type of interaction is blue native polyacrylamide gel electrophoresis (BN-PAGE), which allows for the high-resolution separation of proteins in their native form. These protein complexes can be further discriminated by a second-dimension gel electrophoresis (SDS-PAGE) from lanes cut from BN-PAGE. Once there is no study on the use of bidimensional BN/SDS-PAGE with snake venoms, this study initially standardized the BN/SDS-PAGE technique in order to evaluate protein interactions in Bothrops atrox, Bothrops erythromelas, and Bothrops jararaca snake venoms. Results of BN/SDS-PAGE showed that native protein complexes were present, and that snake venom metalloproteinases and venom serine proteinases maintained their enzymatic activity after BN/SDS-PAGE. C-type lectin-like proteins were identified by Western blotting. Therefore, bidimensional BN/SDS-PAGE proved to be an easy, practical, and efficient method for separating functional venom proteins according to their assemblage in complexes, as well as to analyze their biological activities in further details.

Morphological variation in the common lancehead populations: Sexual dimorphism and ontogenetic patterns

AbstractThe common lancehead Bothrops jararaca is widespread in the Atlantic Forest in Brazil. The species is known to show a marked sexual dimorphism pattern, with the female being larger than the male. However, most efforts in clarifying morphological variation between the sexes are often focused on a single population. In this paper, we investigate how sexual dimorphism and ontogenetic trajectories vary among populations as well as the ontogenetic trajectories of B. jararaca. We analyzed 211 specimens from a coastal and a highland population and measured 17 morphological traits, including linear and meristic characteristics, and the analysis revealed a clear but variable effect of sex and population. Females were larger than males in all evaluated populations. Furthermore, females in the coastal population were generally smaller than in the highland population but had significantly more scales. Widespread species often experience differential environmental pressures even in terms of biotic and abiotic factors. We attribute the results found herein to specificities in prey availability and climatic conditions which affect the ontogenetic pattern between the sexes and the populations, resulting in specific sexual dimorphism patterns.

The severity of acute kidney injury correlates with plasma venom levels in Bothrops atrox envenomings

The Brazilian Amazon has high rates of snakebite envenomings (SBEs), with ∼90% caused by Bothrops atrox. Envenomings by this species can trigger local and systemic effects, such as acute kidney injury (AKI). Our aim was to identify predictors of AKI in Bothrops SBEs in patients from Manaus, Western Brazilian Amazon. A total of 127 patients were enrolled, with a predominance of men between 16 and 45 years old from rural areas. Of the 127 patients, 38.6% developed AKI, with 61.2% presenting stage I, 34.7% presenting stage II and 4.1% presenting stage III severity. The age groups 0–10 years and ≥60 years presented a significantly higher frequency of AKI compared to the 11–40 years group. Moderate/severe edema in the affeccted limb was significantly associated with lower risk of AKI [p = 0.01; OR = 0.11 (95%CI 0.02–0.53)]. Nausea [p = 0.01; OR = 54.44 (95%CI = 3.26–909.27)] and high blood urea levels [p = 0.01; OR = 5.38 (95%CI = 2.12–13.66)] were risk factors for AKI. There was a significant positive correlation between circulating venom levels and the highest creatinine serum values during the hospital stay (p = 0.03) and with the difference between the maximum creatinine levels and the creatinine levels on admission (p = 0.02). A positive correlation between serum venom concentrations and creatinine levels suggests a direct or indirect dose-dependent participation of the venom toxins in the pathogenesis of AKI.

CCL-2 and CXCL-8: Potential Prognostic Biomarkers of Acute Kidney Injury after a Bothrops atrox Snakebite.

In the Brazilian Amazon, the snake Bothrops atrox is the primary cause of snakebites. B. atrox (BaV) venom can cause systemic pathophysiological changes such as acute kidney injury (AKI), which leads to the production of chemokines and cytokines in response to the envenomation. These soluble immunological molecules act by modulating the inflammatory response; however, the mechanisms associated with the development of AKI are still poorly understood. Here, we characterize the profile of these soluble immunological molecules as possible predictive biomarkers of the development of AKI. The study involved 34 patients who had been victims of snakebites by Bothrops sp. These were categorized into two groups according to the development of AKI (AKI(-)/AKI(+)), using healthy donors as the control (HD). Peripheral blood samples were collected at three-time points: before antivenom administration (T0) and at 24 and 48 hours after antivenom (T1 and T2, respectively). The soluble immunological molecules (CXCL-8, CCL-5, CXCL-9, CCL-2, CXCL-10, IL-6, TNF, IL-2, IL-10, IFN-γ, IL-4, and IL-17A) were quantified using cytometric bead array. Our results demonstrated an increase in CXCL-9, CXCL-10, IL-6, IL-2, IL-10, and IL-17A molecules in the groups of patients who suffered Bothrops snakebites (AKI(-) and AKI(+)) before antivenom administration, when compared to HD. In the AKI(+) group, levels of CXCL-8 and CCL-2 molecules were elevated on admission and progressively decreased during the clinical evolution of patients after antivenom administration. In addition, in the signature analysis, these were produced exclusively by the group AKI(+) at T0. Thus, these chemokines may be related to the initiation and extension of AKI after envenomation by Bothrops and present themselves as two potential biomarkers of AKI at T0.

Determination of the species origin and thrombin-like enzyme content of Bothrops atrox venom by ultra-high performance liquid chromatography-tandem mass spectrometry based on marker peptide

蛇毒血凝酶类药物是以蝮蛇蛇毒为原料制备的止血药,主要活性成分为蛇毒类凝血酶(svTLEs)。不同蛇种来源的svTLEs结构不同,止血机制不同,药理作用也存在差异,因此准确鉴别蛇毒种属来源和svTLEs含量对于保障该类产品的质量至关重要。研究基于蛋白质组学技术,筛选出了具有种属特异性的矛头蝮蛇svTLE特征肽,并建立了基于特征肽的超高效液相色谱-串联质谱(UHPLC-MS/MS)检测矛头蝮蛇蛇毒种属来源及类凝血酶含量的方法。采用胰蛋白酶对纯化的矛头蝮蛇svTLE进行酶解,利用纳升液相色谱-四极杆/静电场轨道阱高分辨质谱(Nano LC-Q-Exactive-MS)和Proteome Discoverer 2.2软件分别进行多肽的检测和鉴定,通过BLAST搜索与Uniprot数据库对比分析,筛选出具有种属特异性的矛头蝮蛇svTLEs特征肽“EAYNGLPAK”。针对该特征肽对酶解温度、酶解时间和酶用量等样品前处理方法进行了优化,利用超高效液相色谱-串联质谱,以m/z 481.9>315.2和481.9>485.2作为检测离子对,采用ESI+模式进行了多反应监测(MRM)定性定量分析。结果显示,特征肽在2.5~30 ng/mL范围内线性关系良好,相关系数(r)大于0.9996,多水平加标回收率范围为95.5%~101.9%,各水平平行测定结果的相对标准偏差(RSD)为1.1%~3.2%,完全能够满足实际样品检测需求。方法简便快捷,灵敏度高,专属性强,可用于矛头蝮蛇蛇毒种属鉴别及svTLE含量测定,从源头保证血凝酶类产品的质量,并可为其他蛇毒类产品的质量控制提供参考。

04. Segmental muscle twitching behaviour in the flanks of lancehead vipers Bothrops spp in response to human approach

ABSTRACT - Bothrops species are known to have a wide range of defensive behaviours against potential threats. Herein we show a frequently observed, but to date undocumented, behaviour in male and female Bothrops spp of varying sizes in newly arrived specimens from the wild, short-or long-term captives as well as in captive born individuals. The behaviour consists of irregular, synchronous or asynchronous muscular twitches in segments of the body flanks in otherwise motionless snakes. We named this ‘Segmental Muscle Twitching Behaviour’ (SMTB). We observed fifteen Bothrops spp from six species groups for incidence of this behaviour and made videos of snakes during the ‘alertness’ and ‘threatening’ phases of response to human approach. We found the behaviour in only five species, these belong to the monophyletic Bothrops jararacussu and Bothrops atrox species groups, suggesting a single evolutionary origin of this behaviour. Macroscopically, SMTB varied in the number of segments involved and the twitches had uneven intensities. Although recurrent and often replicable in similar situations during human approach, the behaviour was not displayed consistently. In addition, SMTB can be interrupted, stay inactive for quite some time and then restart. Hypotheses to explain this behaviour are suggested.