Insight into the adaptive role of arachnid genome-wide duplication through chromosome-level genome assembly of the Western black widow spider.

Although spiders are one of the most diverse groups of arthropods, the genetic architecture of their evolutionary adaptations is largely unknown. Specifically, ancient genome-wide duplication occurring during arachnid evolution ~450 mya resulted in a vast assembly of gene families, yet the extent to which selection has shaped this variation is understudied. To aid in comparative genome sequence analyses, we provide a chromosome-level genome of the Western black widow spider (Latrodectus hesperus)-a focus due to its silk properties, venom applications, and as a model for urban adaptation. We used long-read and Hi-C sequencing data, combined with transcriptomes, to assemble 14 chromosomes in a 1.46 Gb genome, with 38,393 genes annotated, and a BUSCO score of 95.3%. Our analyses identified high repetitive gene content and heterozygosity, consistent with other spider genomes, which has led to challenges in genome characterization. Our comparative evolutionary analyses of eight genomes available for species within the Araneoidea group (orb weavers and their descendants) identified 1,827 single-copy orthologs. Of these, 155 exhibit significant positive selection primarily associated with developmental genes, and with traits linked to sensory perception. These results support the hypothesis that several traits unique to spiders emerged from the adaptive evolution of ohnologs-or retained ancestrally duplicated genes-from ancient genome-wide duplication. These comparative spider genome analyses can serve as a model to understand how positive selection continually shapes ancestral duplications in generating novel traits today within and between diverse taxonomic groups.

The functional microclimate of an urban arthropod pest: Urban heat island temperatures in webs of the western black widow spider.

Urbanization alters natural landscapes and creates unique challenges for urban wildlife. Similarly, the Urban Heat Island (UHI) effect can produce significantly elevated temperatures in urban areas, and we have a relatively poor understanding of how this will impact urban biodiversity. In particular, most studies quantify the UHI using broad-scale climate data rather than assessing microclimate temperatures actually experienced by organisms. In addition, studies often fail to address spatial and temporal complexities of the UHI. Here we examine the thermal microclimate and UHI experienced in the web of Western black widow spiders (Latrodectus hesperus), a medically-important, superabundant urban pest species found in cities across the Western region of North America. We do this using replicate urban and desert populations across an entire year to account for seasonal variation in the UHI, both within and between habitats. Our findings reveal a strong nighttime, but no daytime, UHI effect, with urban spider webs being 2-5 °C warmer than desert webs at night. This UHI effect is most prominent during the spring and least prominent in winter, suggesting that the UHI need not be most pronounced when temperatures are most elevated. Urban web temperatures varied among urban sites in the daytime, whereas desert web temperatures varied among desert sites in the nighttime. Finally, web temperature was significantly positively correlated with a spider's boldness, but showed no relationship with voracity towards prey, web size, or body condition. Understanding the complexities of each organism's thermal challenges, the "functional microclimate", is crucial for predicting the impacts of urbanization and climate change on urban biodiversity and ecosystem functioning.

Proline-Tyrosine Ring Interactions in Black Widow Dragline Silk Revealed by Solid-State Nuclear Magnetic Resonance and Molecular Dynamics Simulations.

Selective one-dimensional 13C-13C spin-diffusion solid-state nuclear magnetic resonance (SSNMR) provides evidence for CH/π ring packing interactions between Pro and Tyr residues in 13C-enriched Latrodectus hesperus dragline silk. The secondary structure of Pro-containing motifs in dragline spider silks consistently points to an elastin-like type II ß-turn conformation based on 13C chemical shift analysis. 13C-13C spin diffusion measurements as a function of mixing times allow for the measurement of spatial proximity between the Pro and Tyr rings to be ∼0.5-1 nm, supporting strong Pro-Tyr ring interactions that likely occur through a CH/π mechanism. These results are supported by molecular dynamics (MD) simulations and analysis and reveals new insights into the secondary structure and Pro-Tyr ring stacking interactions for one of nature's toughest biomaterials.

Research on improved black widow algorithm for medical image denoising.

Improving the quality of medical images is crucial for accurate clinical diagnosis; however, medical images are often disrupted by various types of noise, posing challenges to the reliability and diagnostic accuracy of the images. This study aims to enhance the Black Widow optimization algorithm and apply it to the task of denoising medical images to improve both the quality of medical images and the accuracy of diagnostic results. By introducing Tent mapping, we refined the Black Widow optimization algorithm to better adapt to the complex features of medical images. The algorithm's denoising capabilities for various types of noise were enhanced through the combination of multiple filters, all without the need for training each time to achieve preset goals. Simulation results, based on processing a dataset containing 1588 images with Gaussian, salt-and-pepper, Poisson, and speckle noise, demonstrated a reduction in Mean Squared Error (MSE) by 0.439, an increase in Peak Signal-to-Noise Ratio (PSNR) by 4.315, an improvement in Structural Similarity Index (SSIM) by 0.132, an enhancement in Edge-to-Noise Ratio (ENL) by 0.402, and an increase in Edge Preservation Index (EPI) by 0.614. Simulation experiments verified that the proposed algorithm has a certain advantage in terms of computational efficiency. The improvement, incorporating Tent mapping and a combination of multiple filters, successfully elevated the performance of the Black Widow algorithm in medical image denoising, providing an effective solution for enhancing medical image quality and diagnostic accuracy.

Aranhas de interesse médico no Brasil / Spiders of medical interest in Brazil

O documento apresenta informações sobre aranhas de importância médica no Brasil. Descreve a estrutura externa das aranhas e destaca três gêneros de importância em saúde pública: aranha-marrom (Loxosceles), aranha-armadeira ou macaca (Phoneutria) e viúva-negra (Latrodectus). Traz imagens dessas espécies e lista sinais, sintomas e tratamento para acidentes com elas. Apresenta dados de série histórica de acidentes por aranhas no Brasil e Tocantins entre 2000-2022. Por fim, traz recomendações sobre prevenção e primeiro atendimento para acidentes com aranhas.

The document provides information on medically significant spiders in Brazil. It describes the external structure of spiders and highlights three genera of public health importance: brown recluse spider (Loxosceles), wandering spider or macaque spider (Phoneutria), and black widow spider (Latrodectus). It includes images of these species and lists signs, symptoms, and treatment for accidents involving them. It presents historical data on spider-related accidents in Brazil and Tocantins between 2000-2022. Finally, it provides recommendations for prevention and initial first aid for spider bites.

El documento proporciona información sobre arañas de importancia médica en Brasil. Describe la estructura externa de las arañas y destaca tres géneros de importancia para la salud pública: la araña de rincón (Loxosceles), la araña errante o araña mono (Phoneutria) y la viuda negra (Latrodectus). Incluye imágenes de estas especies y enumera los signos, síntomas y tratamiento para accidentes con ellas. Presenta datos históricos sobre accidentes relacionados con arañas en Brasil y Tocantins entre 2000 y 2022. Por último, proporciona recomendaciones para la prevención y la atención de primeros auxilios en caso de picaduras de araña.

Reversible Myocarditis Following Black Widow Spider (Latrodectus spp.) Bite in Egypt: A case report.

Black widow spiders (BWSs) are poisonous spiders of the Arthropoda phylum that live in the Mediterranean region. The effects of BWS bites ranges from local damage to systemic manifestations including paresthesia, stiffness, abdominal cramps, nausea, vomiting, headache, anxiety, hypertension and tachycardia. However, cardiac involvement following a BWS bite is uncommon. We report a 35-year-old male patient who presented to a tertiary hospital in Menoufia, Egypt, in 2019 and developed acute pulmonary oedema with electrocardiogram (ECG) changes that showed ST elevation in leads I and aVL with reciprocal ST segment depression in infero-lateral leads with elevated cardiac biomarkers. Echocardiography showed regional wall motion abnormalities with an impaired ejection fraction of 42%. The condition was reversible after one week of supportive treatment and the patient was discharged from the hospital with normal electrocardiogram, ejection fraction and negative cardiac markers. A routine cardiac evaluation, serial ECG, serial cardiac markers and echocardiography should be considered for any patient exposed to a BWS bite for detection of any potentially fatal cardiac abnormalities.

Web Vibrations in Intraspecific Contests of Female Black Widow Spiders, Latrodectus hesperus.

Female black widow spiders, Latrodectus hesperus Chamberlin and Ivie (Araneae: Theridiidae), are solitary predators of arthropods with no tolerance for intruders on the webs. In California, L. hesperus are found in urban and agricultural settings and can be a phytosanitary pest in fresh produce. Spatial separation of L. hesperus webs could be determined by seasonal population densities, with territorial competition expected under high densities in the environment. However, little is known about female-female communication behaviors in this species. In 1-hr laboratory observations, displays of female-female rivalry included production of vibrational signals in a majority (20 of 30) of trials. The number of signals produced by both females was highest during the initial 10 min of trials, with signaling rate (time interval between signals) peaking during the 40-50 min observation period. The overall ratio of signals produced by the resident female and the introduced female was about 5:1, with the number of signals produced by the resident female higher than the number of signals produced by the introduced female. Analysis of rivalry signals showed a peak in magnitude (about 0.4 m/s) ranging from 6 to 23 Hz and smaller peaks at about 29, 38, and 47 Hz. Collectively, these results demonstrate that female L. hesperus exhibit territorial rivalry and that female-female rivalry is mediated by emission of vibrational signals through the web. Understanding the mechanisms of intraspecific competition in L. hesperus is required for elucidating interspecific interactions in the environment and may lead to development of novel methods to prevent spiders from colonizing crops.

Injected serotonin decreases foraging aggression in black widow spiders (Latrodectus hesperus), but dopamine has no effect.

A fundamental goal of animal behavior research is to discover the proximate mechanisms driving individual behavioral differences. Biogenic amines are known to mediate various aspects of behavior across many species, including aggression, one of the most commonly measured behavioral traits in animals. Arthropods provide an excellent system to manipulate biogenic amines and quantify subsequent behavioral changes. Here, we investigated the role of dopamine (DA) and serotonin (5-HT) on foraging aggression in western black widow spiders (Latrodectus hesperus), as measured by the number of attacks on a simulated prey animal in the web. We injected spiders with DA or 5-HT and then quantified subsequent changes in behavior over 48 h. Based on previous work on insects and spiders, we hypothesized that increasing DA levels would increase aggression, while increasing 5-HT would decrease aggression. We found that injection of 5-HT did decrease black widow foraging aggression, but DA had no effect. This could indicate that the relationship between DA and aggression is complex, or that DA may not play as important a role in driving aggressive behavior as previously thought, at least in black widow spiders. Aggressive behavior is likely also influenced by other factors, such as inter-individual differences in genetics, metabolic rates, environment, and other neurohormonal controls.

Case Report: Soldier With Latrodectism After Black Widow Spider Bite During a Field Training Exercise.

Latrodectism from black widow spider (BWS) bites is rare in the United States. Latrodectism is a severe systemic manifestation of the envenomation that includes severe abdominal pain mimicking acute surgical abdomen and, in rare cases, could lead to acute myocarditis and rhabdomyolysis. The BWS typically inhabits dark, low-lying areas such as woodpiles, tree stumps, outdoor storage, outdoor furniture, outdoor toilets, and rock piles and is most active during warm weather months. Military service members often participate in field training exercises during warm weather in wooded areas littered with woodpiles and tree stumps; therefore, they are at an increased risk for bites by arachnids. We report the case of a 26-year-old active duty male soldier evacuated from field training with latrodectism and possible envenomation-induced myocarditis after a suspected BWS bite.

Neutralization of black widow spider (Latrodectus mactans) venom with rabbit polyclonal serum hyperimmunized with recombinant alpha-latrotoxin fragments.

Alpha-latrotoxin (ɑLTx) is the component responsible for causing the pathophysiology in patients bitten by spiders from the genus Latrodectus, commonly known as black widow spiders. The current antivenom used to treat these envenomations in Mexico is produced using the venom of thousands of spiders, obtained through electrical stimulation. This work aimed to produce this protein as well as two of its fragments in a bacterial model, to evaluate their use as immunogens to produce neutralizing hyperimmune sera, in rabbits. ɑLTx is a 130 kDa protein which has not yet been obtained in a soluble active form using bacterial models. In the present work, ɑLTx and two of its fragments, ankyrin domain and amino terminal domain (LTxAnk and LTxNT) were produced in bacteria and solubilized from inclusion bodies using N-lauroyl sarcosine. These three proteins were used for hyperimmunization in order to evaluate their potential as immunogens for the production of neutralizing hyperimmune sera against the complete venom of Latrodectus mactans. The hyperimmune sera obtained using the complete ɑLTx as well as the LTxNT, was capable of preventing death of mice envenomated with 3 LD50s of venom, both in preincubation and rescue experiments. Conversely, the serum obtained using the LTxAnk fragment, generated only partial protection and a delay in the time of death, even with a maximum dose of 450 µL. We therefore conclude that the produced proteins show great potential for their use as immunogens and should be further tested in large animals, such as horses.

Chromosome-level genome assembly of the black widow spider Latrodectus elegans illuminates composition and evolution of venom and silk proteins.

BACKGROUND: The black widow spider has both extraordinarily neurotoxic venom and three-dimensional cobwebs composed of diverse types of silk. However, a high-quality reference genome for the black widow spider was still unavailable, which hindered deep understanding and application of the valuable biomass. FINDINGS: We assembled the Latrodectus elegans genome, including a genome size of 1.57 Gb with contig N50 of 4.34 Mb and scaffold N50 of 114.31 Mb. Hi-C scaffolding assigned 98.08% of the genome to 14 pseudo-chromosomes, and with BUSCO, completeness analysis revealed that 98.4% of the core eukaryotic genes were completely present in this genome. Annotation of this genome identified that repetitive sequences account for 506.09 Mb (32.30%) and 20,167 protein-coding genes, and specifically, we identified 55 toxin genes and 26 spidroins and provide preliminary analysis of their composition and evolution. CONCLUSIONS: We present the first chromosome-level genome assembly of a black widow spider and provide substantial toxin and spidroin gene resources. These high-qualified genomic data add valuable resources from a representative spider group and contribute to deep exploration of spider genome evolution, especially in terms of the important issues on the diversification of venom and web-weaving pattern. The sequence data are also firsthand templates for further application of the spider biomass.

Coexistence of Rhabdomyolysis, Myocarditis and Arrhythmia after Spider Bite: A Case Report.

BACKGROUND: Rhabdomyolysis after spider bite has been reported in a small number of patients, and myocarditis in even fewer. However, arrhythmia associated with latrodectism in children has not been described in the literature to date. CASE SUMMARY: A girl presented approximately 4.5 h after being bitten on the left ankle by a black spider. Two unifocal premature ventricular contractions (PVCs) were observed on the electrocardiogram. In laboratory tests, creatine kinase was elevated. On day 2, levels of troponin, pro-brain and natriuretic peptide were elevated. Electrocardiogram revealed inverted and biphasic T waves. Echocardiography revealed mild left ventricular dilation, mitral and aortic valve regurgitation. Holter electrocardiogram showed PVCs. Her laboratory and echocardiography findings completely normalized after discharge, and no arrhythmia was observed on the Holter electrocardiogram during outpatient follow-up. CONCLUSION: Although spider bites are uncommon, they can cause serious systemic effects. These patients should be evaluated for arrhythmia, rhabdomyolysis and myocarditis.

Rarely, spider bites can cause serious systemic effects, severe morbidity and death. In a small number of patients, spider envenomation causes rhabdomyolysis and myocarditis. In the present case, the elevated troponin and pro-brain natriuretic peptide levels and electrocardiogram/echocardiography findings were consistent with myocarditis, and an increase in creatinine kinase level indicated rhabdomyolysis. In addition, the electrocardiogram and Holter electrocardiogram revealed unifocal premature ventricular contraction. To our knowledge, arrhythmia due to Latrodectus spider bite has not been described in children to date. In addition, this case demonstrates the coexistence of two serious systemic effects, rhabdomyolysis and myocarditis, with full recovery after appropriate treatment.

Ecdysteroid responses to urban heat island conditions during development of the western black widow spider (Latrodectus hesperus).

The steroid hormone 20-hydroxyecdysone (20E) controls molting in arthropods. The timing of 20E production, and subsequent developmental transitions, is influenced by a variety of environmental factors including nutrition, photoperiod, and temperature, which is particularly relevant in the face of climate change. Environmental changes, combined with rapid urbanization, and the increasing prevalence of urban heat islands (UHI) have contributed to an overall decrease in biodiversity making it critical to understand how organisms respond to elevating global temperatures. Some arthropods, such as the Western black widow spider, Latrodectus hesperus, appear to thrive under UHI conditions, but the physiological mechanism underlying their success has not been explored. Here we examine the relationship between hemolymph 20E titers and spiderling development under non-urban desert (27°C), intermediate (30°C), and urban (33°C) temperatures. We found that a presumptive molt-inducing 20E peak observed in spiders at non-urban desert temperatures was reduced and delayed at higher temperatures. Intermolt 20E titers were also significantly altered in spiders reared under UHI temperatures. Despite the apparent success of black widows in urban environments, we noted that, coincident with the effects on 20E, there were numerous negative effects of elevated temperatures on spiderling development. The differential effects of temperature on pre-molt and intermolt 20E titers suggest distinct hormonal mechanisms underlying the physiological, developmental, and behavioral response to heat, allowing spiders to better cope with urban environments.

First Record of Black Widow Spider Bite Latrodectus cinctus (Araneae: Theridiidae) From Iran.

The genus Latrodectus contains the most medically important spiders around the world. This study describes the first case of Latrodectus cinctus Blackwall, 1865 bite and clinical treatment from Iran. Also, it is the first collection report from the southeast of the country that can enhance prior knowledge on the geographical distribution of this species. We describe a 42-year-old female patient with neurological pain caused by the spider bite. Also, a summary of the entomological survey and morphological identification of the collected species from the patient's house is presented.

Expression of Brown and Southern Black Widow Spider (Araneae: Theridiidae) Latrotoxins Is Tissue- and Life Stage-Specific for α-Latroinsectotoxins and δ-Latroinsectotoxins and Is Ubiquitous for α-Latrotoxins.

Widow spiders are widely known for their potent venom toxins that make them among the few spiders of medical concern. The latrotoxins are the most well-studied widow toxins and include both the vertebrate-specific latrotoxins and the insect-specific latroinsectotoxins (LITs). Previous studies have shown that toxins are not limited to expression in the venom glands of adult spiders; however, gaps exist in latrotoxin screening across all life stages for brown widows, Latrodectus geometricus and southern black widows, Latrodectus mactans. In this study, we screened male and female venom gland, cephalothorax, and abdomen tissues, spiderling cephalothorax and abdomen tissues, and eggs of both L. geometricus and L. mactans, for the presence of three latrotoxins: α-latrotoxin (α-LTX), and α- and δ-latroinsectotoxins (α/δ-LITs). Widows were locally collected. Extracted RNA was used to prepare cDNA that was analyzed by PCR for the presence or absence of latrotoxin expression. Results show that expression profiles between the two species are very similar but not identical. Expression of α-LTX was found in all life stages in all tissues examined for both species. For both species, no LIT expression was detected in eggs and variable patterns of α-LIT expression were detected in spiderlings and adults. Notably, δ-LIT could only be detected in females for both species. Our results show that latrotoxin expression profiles differ within and between widow species. Data on their expression distribution provide further insight into the specific latrotoxins that contribute to toxicity profiles for each life stage in each species and their specific role in widow biology.

Bites by the noble false widow spider Steatoda nobilis can induce Latrodectus-like symptoms and vector-borne bacterial infections with implications for public health: a case series.

CONTEXT: In recent years, the Noble false widow spider Steatoda nobilis (Thorell, 1875) has expanded its range globally and may represent a potential threat to native ecosystems and public health. Increasing numbers in synanthropic habitats have led to more human encounters and envenomations. Steatoda nobilis bites were previously classed as medically significant with similarities to bites from true black widows of the genus Latrodectus but deemed milder in onset, with symptoms generally ranging from mild to moderate. CASE DETAILS: In this manuscript we present 16 new cases of S. nobilis envenomations bringing the total number of confirmed cases reported in the literature to 24. We report new symptoms and provide discussion on the contributing factors to pathology following bites by S. nobilis. DISCUSSION: We report a range of pathologies including necrosis, Latrodectus-like envenomation symptoms that include debilitating pain, tremors, fatigue, nausea, hypotension, and vectored bacterial infections including cellulitis and dermatitis. Symptoms ranged from mild to severe, requiring hospitalisation in some cases.

Molecular architecture of black widow spider neurotoxins.

Latrotoxins (LaTXs) are presynaptic pore-forming neurotoxins found in the venom of Latrodectus spiders. The venom contains a toxic cocktail of seven LaTXs, with one of them targeting vertebrates (α-latrotoxin (α-LTX)), five specialized on insects (α, ß, γ, δ, ε- latroinsectotoxins (LITs), and one on crustaceans (α-latrocrustatoxin (α-LCT)). LaTXs bind to specific receptors on the surface of neuronal cells, inducing the release of neurotransmitters either by directly stimulating exocytosis or by forming Ca2+-conductive tetrameric pores in the membrane. Despite extensive studies in the past decades, a high-resolution structure of a LaTX is not yet available and the precise mechanism of LaTX action remains unclear. Here, we report cryoEM structures of the α-LCT monomer and the δ-LIT dimer. The structures reveal that LaTXs are organized in four domains. A C-terminal domain of ankyrin-like repeats shields a central membrane insertion domain of six parallel α-helices. Both domains are flexibly linked via an N-terminal α-helical domain and a small ß-sheet domain. A comparison between the structures suggests that oligomerization involves major conformational changes in LaTXs with longer C-terminal domains. Based on our data we propose a cyclic mechanism of oligomerization, taking place prior membrane insertion. Both recombinant α-LCT and δ-LIT form channels in artificial membrane bilayers, that are stabilized by Ca2+ ions and allow calcium flux at negative membrane potentials. Our comparative analysis between α-LCT and δ-LIT provides first crucial insights towards understanding the molecular mechanism of the LaTX family.

Egg Case Protein 3: A Constituent of Black Widow Spider Tubuliform Silk.

Spider silk has outstanding mechanical properties, rivaling some of the best materials on the planet. Biochemical analyses of tubuliform silk have led to the identification of TuSp1, egg case protein 1, and egg case protein 2. TuSp1 belongs to the spidroin superfamily, containing a non-repetitive N- and C-terminal domain and internal block repeats. ECP1 and ECP2, which lack internal block repeats and sequence similarities to the highly conserved N- and C-terminal domains of spidroins, have cysteine-rich N-terminal domains. In this study, we performed an in-depth proteomic analysis of tubuliform glands, spinning dope, and egg sacs, which led to the identification of a novel molecular constituent of black widow tubuliform silk, referred to as egg case protein 3 or ECP3. Analysis of the translated ECP3 cDNA predicts a low molecular weight protein of 11.8 kDa. Real-time reverse transcription-quantitative PCR analysis performed with different silk-producing glands revealed ECP3 mRNA is predominantly expressed within tubuliform glands of spiders. Taken together, these findings reveal a novel protein that is secreted into black widow spider tubuliform silk.

Investigating the Atomic and Mesoscale Interactions that Facilitate Spider Silk Protein Pre-Assembly.

Black widow spider dragline silk is one of nature's high-performance biological polymers, exceeding the strength and toughness of most man-made materials including high tensile steel and Kevlar. Major ampullate (Ma), or dragline silk, is primarily comprised of two spidroin proteins (Sp) stored within the Ma gland. In the native gland environment, the MaSp1 and MaSp2 proteins self-associate to form hierarchical 200-300 nm superstructures despite being intrinsically disordered proteins (IDPs). Here, dynamic light scattering (DLS), three-dimensional (3D) triple resonance solution NMR, and diffusion NMR is utilized to probe the MaSp size, molecular structure, and dynamics of these protein pre-assemblies diluted in 4 M urea and identify specific regions of the proteins important for silk protein pre-assembly. 3D NMR indicates that the Gly-Ala-Ala and Ala-Ala-Gly motifs flanking the poly(Ala) runs, which comprise the ß-sheet forming domains in fibers, are perturbed by urea, suggesting that these regions may be important for silk protein pre-assembly stabilization.

Silently Suffering: A Pediatric Black Widow Spider Envenomation.

BACKGROUND: Black widow spiders are distributed worldwide and, although rarely fatal, account for significant morbidity. Diagnosis can be challenging, and children are at risk of increased morbidity due to their small size. CASE REPORT: We present a case of a 3-year-old boy who was brought to our emergency department because of sudden ear pain followed by labored breathing, abdominal pain, refusal or inability to speak, and grunting respirations. A black widow spider bite was suspected based on additional history obtained, and the spider was found in his helmet, confirming the diagnosis. The patient had progressive respiratory distress and somnolence and was intubated and transferred to a local pediatric intensive care unit. Antivenom was not initially available and eventually declined by the family. The child received supportive care and recovered after several days. Why Should an Emergency Physician Be Aware of This? This case illustrates the potentially deadly effects a black widow envenomation could cause in a child, and that bite location can affect the constellation of symptoms. It is a reminder that toxins, including that of the black widow spider, should be on the differential for acute abdominal pain, especially with autonomic features.