Venomous Loxosceles Species (Araneae, Haplogynae, Sicariidae) from Brazil: 2n♂ = 23 and X1X2Y Sex Chromosome System as Shared Characteristics.

The family Sicariidae comprises the genera Hexophthalma, Sicarius and Loxosceles. This latter is subdivided in eight monophyletic groups based on genitalia morphology and molecular analyses: amazonica, gaucho, laeta, and spadicea (South America); reclusa (North America); rufescens (Mediterranean); spinulosa and vonwredei (Africa). In Brazil, the genus Loxosceles is represented by 50 species. The mitotic and meiotic characteristics of eight Loxosceles species were analyzed in order to discuss the chromosome evolution, as well as the correspondence between cytogenetic data and morphological/molecular data for the delimitation of the South American groups of species belonging to this genus. All species studied in this work showed 2n♂ = 23, including a X1X2Y sex chromosome system (SCS). Despite the similarity of diploid number and SCS, the species studied here differed regarding the chromosome morphology of some autosomal pairs, presence of secondary constrictions, size of X chromosomes and localization of Ag-NOR/rDNA sites. Based on all these chromosomal data, we verified a close relationship between Loxosceles species belonging to the amazonica and gaucho groups. Transmission electron microscopy (TEM) analysis of spread pachytene cells of L. gaucho showed regular synapsis between homologous autosomal chromosomes, but asynaptic behavior of the sex chromosomes. The axial elements of the sex chromosomes undergo conspicuous morphological modifications resulting in shortening of their length.

Peripheral mechanisms involved in Tityus bahiensis venom-induced pain.

Scorpionism is a public health burden in Brazil. Tityus bahiensis is responsible for most accidents in the Southeastern region of Brazil. Here, the hyperalgesic mechanisms of Tityus bahiensis venom were investigated, focusing on the role of pro-inflammatory cytokines (tumor necrosis factor alpha [TNF-α] and interleukin 1 beta [IL-1ß]) and activation of the transcription factor NFκB. Intraplantar (i.pl.) administration of Tityus bahiensis venom (0.2, 0.6, 1.2 and 2.4 µg/20 µL i.pl.) induced mechanical hyperalgesia and thermal hyperalgesia. The 2.4 µg dose of Tityus bahiensis venom induced overt pain-like behavior and increased myeloperoxidase (MPO) and N-acetyl-beta-D-glucosaminidase (NAG) activities, TNF-α and IL-1ß levels in the paw tissue. Systemic pre-treatment with etanercept (soluble TNF-α receptor; 10 mg/kg), IL-1ra (IL-1 receptor antagonist; 30 mg/kg) and pyrrolidine dithiocarbamate (PDTC, nuclear factor kappa B [NFκB] inhibitor; 100 mg/kg) inhibited Tityus bahiensis venom-induced mechanical and thermal hyperalgesia, MPO and NAG activity and overt pain-like behavior. These data demonstrate the involvement of TNF-α and IL-1ß signaling as well as NFκB activation in Tityus bahiensis venom-induced mechanical and thermal hyperalgesia, overt pain-like behavior, and MPO activity and NAG activity, indicating thus, that targeting these mechanisms might contribute to reducing the pain in this scorpionism.

Comparative morphological study of the venom glands of the centipede Cryptops iheringi, Otostigmus pradoi and Scolopendra viridicornis.

Centipedes are widely distributed over all the continents. As they are well adapted to urban areas they can often cause accidents to humans by injecting venom produced in the glands located inside their maxillipeds. The fine morphology of the centipede venom glands is practically unknown. This present study is the first comparative report on the histology, histochemistry and ultrastructure of the venom glands of the centipede species responsible for the majority of accidents to humans in Brazil: Scolopendra viridicornis, Cryptops iheringi and Otostigmus pradoi. In all species the glands are basically composed of columnar secretory cells radially disposed side by side, individually opening through pores in a central chitinous duct. Each secretory cell is covered by striated muscular fibres. The secretion has the form of small PAS positive granules and large hyaline secretory bromophenol blue positive vacuoles, indicating the presence of neutral polysaccharides and protein. The secretion is conducted through the secretory cell necks to the pores, which open into the central chitinous duct. The results indicate a great similarity both in morphology and primary chemical composition of the venom among the studied species, except for the size of the glands, which is proportional to the body dimensions of each species.

Toxic activities of Brazilian centipede venoms.

Centipedes have a venom gland connected to a pair of forceps, which are used to arrest preys. Human victims bitten by centipedes usually manifest burning pain, paresthesia and edema, which may develop into superficial necrosis. The aim of this work was to characterize and compare toxic activities found in venoms of three species of Brazilian centipedes-Otostigmus pradoi, Cryptops iheringi and Scolopendra viridicornis. By SDS-PAGE (4-20%), important differences were noticed among venoms (between 7 and 205kDa). Few bands showed feeble caseinolytic, fibrinogenolytic and gelatinolytic activities by zymography, but strong hyaluronidase activity was observed in S. viridicornis and O. pradoi venoms. In addition, such activities could be inhibited by o-phenanthroline, indicating that these enzymes are metalloproteinases. All venoms induced nociception, edema and myotoxicity in mice, but only S. viridicornis induced mild hemorrhagic activity. No coagulant activity was detected in centipede venoms. Low phospholipase A(2) activity was observed exclusively in S. viridicornis and O. pradoi venoms, but these venoms had intense direct hemolytic activity on human erythrocytes. Cross-reactivity among venoms was observed using species-specific sera raised in rabbits. Differences were noticed among centipede venoms, but S. viridicornis is indeed the most toxic venom and thereby it could induce a more severe envenomation.

A comparative study of pathophysiological alterations in scorpionism induced by Tityus serrulatus and Tityus bahiensis venoms.

Scorpionism is a relevant public health problem in several countries in tropical and subtropical regions. In Brazil, Tityus serrulatus sting can induce acute lung injury in part as a consequence of inflammation. Despite the occurrence of other scorpions of Tityus genus in Brazilian scorpiofauna, the knowledge regarding pulmonary alterations is related to T. serrulatus venom (Tsv). Here we studied, comparatively, the pathophysiological changes in the rat airways envenomed by Tsv or T. bahiensis venom (Tbv), since both scorpions are involved in human accidents but with severe envenomations occurring when victims are stung by T. serrulatus. After intravenous injection of the venoms (200 µg/kg), both were able to induce Evans blue extravasation (in 30 min) into airways and increased protein extravasation into lungs at 4 and 24 h, but the magnitude of such events was higher in Tsv group. Hemorrhage (in 60 min) in the lungs was higher in Tbv group, while IL-1ß (at 1 h) and IL-6 (at 1 and 4 h) in lung homogenates were detected only in Tsv group. Four and 24 h after envenomation, myeloperoxidase activity in lung was equally augmented in the envenomed groups, as well as an increased in polymorphonuclear cell numbers in bronchoalveolar lavage fluid. At 4 h blood leukogram showed increased leukocyte values with the highest neutrophilia in Tsv group. The numbers of leukocytes and neutrophils remained higher than control at 24 h in Tsv and Tbv groups, and it was accompanied by lympho (envenomed groups) and monocytosis (Tsv group). In conclusion, although Tbv was capable of inducing acute lung injury and blood leukocyte mobilization, most of the evaluated parameters were more affected by the Tsv. These results could help to explain the pathophysiology of the scorpionism and the clinical data arguing toward the greatest severity associated with T. serrulatus stings.

Venomous Loxosceles Species (Araneae, Haplogynae, Sicariidae) from Brazil: 2nmarte= 23 and X1X2Y sex chromosome system as shared characteristics

The family Sicariidae comprises the genera Hexophthalma, Sicarius and Loxosceles. This latter is subdivided in eight monophyletic groups based on genitalia morphology and molecular analyses: amazonica, gaucho, laeta, and spadicea (South America); reclusa (North America); rufescens (Mediterranean); spinulosa and vonwredei (Africa). In Brazil, the genus Loxosceles is represented by 50 species. The mitotic and meiotic characteristics of eight Loxosceles species were analyzed in order to discuss the chromosome evolution, as well as the correspondence between cytogenetic data and morphological/molecular data for the delimitation of the South American groups of species belonging to this genus. All species studied in this work showed 2nmarte = 23, including a X1X2Y sex chromosome system (SCS). Despite the similarity of diploid number and SCS, the species studied here differed regarding the chromosome morphology of some autosomal pairs, presence of secondary constrictions, size of X chromosomes and localization of Ag-NOR/rDNA sites. Based on all these chromosomal data, we verified a close relationship between Loxosceles species belonging to the amazonica and gaucho groups. Transmission electron microscopy (TEM) analysis of spread pachytene cells of L. gaucho showed regular synapsis between homologous autosomal chromosomes, but asynaptic behavior of the sex chromosomes. The axial elements of the sex chromosomes undergo conspicuous morphological modifications resulting in shortening of their length.

Peripheral mechanisms involved in Tityus bahiensis venom-induced pain

Scorpionism is a public health burden in Brazil. Tityus bahiensis is responsible for most accidents in the Southeastern region of Brazil. Here, the hyperalgesic mechanisms of Tityus bahiensis venom were investigated, focusing on the role of pro-inflammatory cytokines (tumor necrosis factor alpha [TNF-α] and interleukin 1 beta [IL-1β]) and activation of the transcription factor NFκB. Intraplantar (i.pl.) administration of Tityus bahiensis venom (0.2, 0.6, 1.2 and 2.4 μg/20 μL i.pl.) induced mechanical hyperalgesia and thermal hyperalgesia. The 2.4 μg dose of Tityus bahiensis venom induced overt pain-like behavior and increased myeloperoxidase (MPO) and N-acetyl-beta-D-glucosaminidase (NAG) activities, TNF-α and IL-1β levels in the paw tissue. Systemic pre-treatment with etanercept (soluble TNF-α receptor; 10 mg/kg), IL-1ra (IL-1 receptor antagonist; 30 mg/kg) and pyrrolidine dithiocarbamate (PDTC, nuclear factor kappa B [NFκB] inhibitor; 100 mg/kg) inhibited Tityus bahiensis venom-induced mechanical and thermal hyperalgesia, MPO and NAG activity and overt pain-like behavior. These data demonstrate the involvement of TNF-α and IL-1β signaling as well as NFκB activation in Tityus bahiensis venom-induced mechanical and thermal hyperalgesia, overt pain-like behavior, and MPO activity and NAG activity, indicating thus, that targeting these mechanisms might contribute to reducing the pain in this scorpionism.

Enzymatic characterization, antigenic cross-reactivity and neutralization of dermonecrotic activity of five Loxosceles spider venoms of medical importance in the Americas.

Loxosceles spiders have a wide distribution in the temperate and tropical regions of the world. Loxoscelism is characterized by necrotic skin ulceration at the bite site and, less commonly, a systemic illness that may be fatal. The purpose of this study was to characterize and compare aspects of the major medically important Loxosceles spider venoms in a standardized manner, particularly considering their neutralization by two Brazilian antivenoms. By SDS-PAGE (12% acrylamide), Loxosceles deserta, Loxosceles gaucho, Loxosceles intermedia, Loxosceles laeta and Loxosceles reclusa venoms had similar electrophoretic profiles, with the major protein bands of 32-35 kDa. All venoms exhibited gelatinolytic, caseinolytic and fibrinogenolytic activities in vitro with a large array of proteases, mainly between 18.1 and 31.8 kDa. Most of these enzymes were metalloproteases as this activity was abolished by 1,10-phenanthroline. Hyaluronidase activity was detected in a protein band of approximately 44 kDa in all venoms. Sphingomyelinase activity was demonstrated in all five venoms. Antigenic cross-reactivity, by Western blotting, was also observed among all venoms studied using commercial equine antivenoms produced in Brazil (Institute Butantan and CPPI). These antivenoms recognized mainly components between 25 and 40 kDa in all venoms with several minor components of >89 kDa. Strong cross-reactivity was also seen among all venoms through the ELISA technique (titre range: 64,000-512,000). All venoms (5 microg doses) induced a similar local reaction when injected intradermally into the flank of rabbits, demonstrating dermonecrosis, hemorrhage, vasoconstriction, edema, and erythema. However, no reaction was observed when each venom was pre-incubated (1 h, 37 degrees C) with Brazilian commercial sera prior to injection. The antivenoms also abolished the sphingomyelinase activity in vitro, suggesting the venoms of the major medically important Loxosceles spider species have generally similar toxic and enzymatic characteristics. Thus, as Brazilian commercial antivenoms are able to neutralize the dermonecrosis induced by Loxosceles venoms of diverse geographical origin, clinical studies should be undertaken on the potential for a single global Loxosceles antivenom.

Venomous Loxosceles Species (Araneae, Haplogynae, Sicariidae) from Brazil: 2nmarte= 23 and X1X2Y sex chromosome system as shared characteristics

The family Sicariidae comprises the genera Hexophthalma, Sicarius and Loxosceles. This latter is subdivided in eight monophyletic groups based on genitalia morphology and molecular analyses: amazonica, gaucho, laeta, and spadicea (South America); reclusa (North America); rufescens (Mediterranean); spinulosa and vonwredei (Africa). In Brazil, the genus Loxosceles is represented by 50 species. The mitotic and meiotic characteristics of eight Loxosceles species were analyzed in order to discuss the chromosome evolution, as well as the correspondence between cytogenetic data and morphological/molecular data for the delimitation of the South American groups of species belonging to this genus. All species studied in this work showed 2nmarte = 23, including a X1X2Y sex chromosome system (SCS). Despite the similarity of diploid number and SCS, the species studied here differed regarding the chromosome morphology of some autosomal pairs, presence of secondary constrictions, size of X chromosomes and localization of Ag-NOR/rDNA sites. Based on all these chromosomal data, we verified a close relationship between Loxosceles species belonging to the amazonica and gaucho groups. Transmission electron microscopy (TEM) analysis of spread pachytene cells of L. gaucho showed regular synapsis between homologous autosomal chromosomes, but asynaptic behavior of the sex chromosomes. The axial elements of the sex chromosomes undergo conspicuous morphological modifications resulting in shortening of their length.

A comparative study of pathophysiological alterations in scorpionism induced by Tityus serrulatus and Tityus bahiensis venoms

Scorpionism is a relevant public health problem in several countries in tropical and subtropical regions. In Brazil, Tityus serrulatus sting can induce acute lung injury in part as a consequence of inflammation. Despite the occurrence of other scorpions of Tityus genus in Brazilian scorpiofauna, the knowledge regarding pulmonary alterations is related to T. serrulatus venom (Tsv). Here we studied, comparatively, the pathophysiological changes in the rat airways envenomed by Tsv or T. bahiensis venom (Tbv), since both scorpions are involved in human accidents but with severe envenomations occurring when victims are stung by T. serrulatus. After intravenous injection of the venoms (200 mu g/kg), both were able to induce Evans blue extravasation (in 30 min) into airways and increased protein extravasation into lungs at 4 and 24 h, but the magnitude of such events was higher in Tsv group. Hemorrhage (in 60 min) in the lungs was higher in Tbv group, while IL-1 beta (at 1 h) and IL-6 (at 1 and 4 h) in lung homogenates were detected only in Tsv group. Four and 24 h after envenomation, myeloperoxidase activity in lung was equally augmented in the envenomed groups, as well as an increased in polymorphonuclear cell numbers in bronchoalveolar lavage fluid. At 4 h blood leukogram showed increased leukocyte values with the highest neutrophilia in Tsv group. The numbers of leukocytes and neutrophils remained higher than control at 24 h in Tsv and Tbv groups, and it was accompanied by lympho (envenomed groups) and monocytosis (Tsv group). In conclusion, although Tbv was capable of inducing acute lung injury and blood leukocyte mobilization, most of the evaluated parameters were more affected by the Tsv. These results could help to explain the pathophysiology of the scorpionism and the clinical data arguing toward the greatest severity associated with T. serrulatus stings.

Local inflammatory reaction induced by Scolopendra viridicornis centipede venom in mice.

Centipede envenomation is generally mild, and human victims usually manifest burning pain, erythema and edema. Despite the abundance and ubiquity of these animals, centipede venom has been poorly characterized in literature. For this reason, the aim of this work was to investigate local inflammatory features induced by Scolopendra viridicornis centipede envenomation in mice, evaluating edema formation, leukocyte infiltration, production of inflammatory mediators, and also performing histological analysis. The highest edematogenic activity induced by the venom, determined by plethysmometry, was noticed 0.5 h after injection in mice footpad. At 24 h, edema was still detected in animals that received 15 and 60 µg of venom, and at 48 h, only in animals injected with 60 µg of venom. In relation to leukocyte count, S. viridicornis venom induced cell recruitment, mainly neutrophils and monocytes/macrophages, in all doses and time periods analyzed in comparison with PBS-injected mice. An increase in lymphocytes was detected especially between 1 and 24 h at 60 µg dose. Besides, eosinophil recruitment was observed mainly for 15 and 60 µg doses in early time periods. Edema formation and cell recruitment were also confirmed by histological analysis. Moreover, S. viridicornis venom stimulated the release of IL-6, MCP-1, KC, and IL-1ß. Conversely, S. viridicornis venom did not induce the release of detectable levels of TNF-α. We demonstrated that the edematogenic activity induced by S. viridicornis venom was of rapid onset, and the venom stimulated secretion of pro-inflammatory mediators which contribute to the inflammatory reaction induced by S. viridicornis venom in an experimental model.

A comparative study of pathophysiological alterations in scorpionism induced by Tityus serrulatus and Tityus bahiensis venoms

Scorpionism is a relevant public health problem in several countries in tropical and subtropical regions. In Brazil, Tityus serrulatus sting can induce acute lung injury in part as a consequence of inflammation. Despite the occurrence of other scorpions of Tityus genus in Brazilian scorpiofauna, the knowledge regarding pulmonary alterations is related to T. serrulatus venom (Tsv). Here we studied, comparatively, the pathophysiological changes in the rat airways envenomed by Tsv or T. bahiensis venom (Tbv), since both scorpions are involved in human accidents but with severe envenomations occurring when victims are stung by T. serrulatus. After intravenous injection of the venoms (200 mu g/kg), both were able to induce Evans blue extravasation (in 30 min) into airways and increased protein extravasation into lungs at 4 and 24 h, but the magnitude of such events was higher in Tsv group. Hemorrhage (in 60 min) in the lungs was higher in Tbv group, while IL-1 beta (at 1 h) and IL-6 (at 1 and 4 h) in lung homogenates were detected only in Tsv group. Four and 24 h after envenomation, myeloperoxidase activity in lung was equally augmented in the envenomed groups, as well as an increased in polymorphonuclear cell numbers in bronchoalveolar lavage fluid. At 4 h blood leukogram showed increased leukocyte values with the highest neutrophilia in Tsv group. The numbers of leukocytes and neutrophils remained higher than control at 24 h in Tsv and Tbv groups, and it was accompanied by lympho (envenomed groups) and monocytosis (Tsv group). In conclusion, although Tbv was capable of inducing acute lung injury and blood leukocyte mobilization, most of the evaluated parameters were more affected by the Tsv. These results could help to explain the pathophysiology of the scorpionism and the clinical data arguing toward the greatest severity associated with T. serrulatus stings.

Predatory behavior of three centipede species of the order Scolopendromorpha (Arthropoda: Myriapoda: Chilopoda)

Studies related to centipede feeding and predatory behavior are rare in the literature, and are limited to observations made during fieldwork. Furthermore, they lack descriptions of prey capture. We conducted a laboratory experiment using South American specimens of Scolopendra viridicornis Newport, 1844 (n = 5), Otostigmus tibialis Brõlemann, 1902 (n = 5), and Cryptops iheringi Brõlemann, 1902 (n = 5), as well as 13 different kinds of prey, to map and describe their predatory behavior. The analysis of video images (65 hours of recordings) resulted in 15 behavioral categories that describe foraging, prey capture, feeding, and cleaning habits. Almost all observations (95%) concluded with the centipede killing the prey. Although we witnessed that a stimulus triggered the movement of the centipede toward the prey in all observation events (suggesting a sit-and-wait strategy), our experiments also showed that these arthropods actively forage to seek food. Field observations during the experiment allowed us to document that scolopendromorphs feed on plants when animal prey items are not available. Moreover, we observed that the size and aggressiveness of the prey determined the centipede capture process. Our results revealed that two behavioral categories were performed only by S. viridicornis , and thus might be genus or species-specific. These are: raising the first third of the body while the rest of the body remains adjacent to the substrate; and restraining the prey along the ventral region of the first third of the body with the aid of locomotory legs. We also observed some peculiar behaviors performed only by O. tibialis . Our results confirm that S. viridicornis , O. tibialis and C. iheringi hold prey between their ultimate pair of legs.

Predatory behavior of three centipede species of the order Scolopendromorpha (Arthropoda: Myriapoda: Chilopoda)

Studies related to centipede feeding and predatory behavior are rare in the literature, and are limited to observations made during fieldwork. Furthermore, they lack descriptions of prey capture. We conducted a laboratory experiment using South American specimens of Scolopendra viridicornis Newport, 1844 (n = 5), Otostigmus tibialis Brõlemann, 1902 (n = 5), and Cryptops iheringi Brõlemann, 1902 (n = 5), as well as 13 different kinds of prey, to map and describe their predatory behavior. The analysis of video images (65 hours of recordings) resulted in 15 behavioral categories that describe foraging, prey capture, feeding, and cleaning habits. Almost all observations (95%) concluded with the centipede killing the prey. Although we witnessed that a stimulus triggered the movement of the centipede toward the prey in all observation events (suggesting a sit-and-wait strategy), our experiments also showed that these arthropods actively forage to seek food. Field observations during the experiment allowed us to document that scolopendromorphs feed on plants when animal prey items are not available. Moreover, we observed that the size and aggressiveness of the prey determined the centipede capture process. Our results revealed that two behavioral categories were performed only by S. viridicornis , and thus might be genus or species-specific. These are: raising the first third of the body while the rest of the body remains adjacent to the substrate; and restraining the prey along the ventral region of the first third of the body with the aid of locomotory legs. We also observed some peculiar behaviors performed only by O. tibialis . Our results confirm that S. viridicornis , O. tibialis and C. iheringi hold prey between their ultimate pair of legs.(AU)

Trap and soil monolith sampled edaphic spiders (arachnida: araneae) in Araucaria angustifolia forest

Forests with Araucaria angustifolia (Bert.) O. Kuntze trees are endangered in Brazil, and information on the diversity of soil spider families associated to these environments is practically inexistent. The present study was set up to evaluate the abundance and diversity of soil spider families in natural and reforested Araucaria forests, impacted or not by fire, and to identify the most efficient method to collect these organisms. The study was conducted in four areas: native forest with predominance of Araucaria (NF); Araucaria reforestation (R); Araucaria reforestation submitted to an accidental fire (RF); and native grass pasture with native Araucaria and submitted to an intense accidental fire (NPF). Considering both sampling methods (Monolith and Pitfall traps), 20 spider families were identified. The pitfall trap method was more effective as it captured 19 out of the 20 recorded families, while the Monolith method extracted only ten spider families. Spider family abundance and Shannon's diversity index (H) were affected by the employed collection method; the values for these attributes were always higher for the NF and lower for the NPF. Correspondence analysis (CA) showed a spatial separation among spider familiy assemblages from the different studied areas. It is suggested that changes in the abundance of soil spider families in Araucaria forests are mainly caused by recurrent human intervention over the last few years.

As florestas com Araucaria angustifolia (Bert.) O. Kuntze estão ameaçadas de extinção no Brasil, e são praticamente inexistentes as informações sobre a diversidade de famílias de aranhas de solo associadas nestes ambientes. O estudo teve o objetivo de avaliar, em florestas com araucária naturais e reflorestadas, impactadas ou não pela queima acidental, a abundância e diversidade de famílias de aranhas, além de identificar o método mais eficiente para coletar estes organismos. O estudo foi conduzido em quatro áreas: floresta nativa com predominância de araucária (NF); reflorestamento de araucária (R); reflorestamento de araucária submetido a incêndio acidental (RF); e pastagem natural com araucárias nativas e ocorrência de incêndio acidental (NPF). Considerando os dois métodos de amostragem (Monólito e armadilhas de solo), foram identificadas 20 famílias de aranhas associadas às áreas. O método das armadilhas de solo foi mais eficiente, capturando 19 das 20 famílias registradas, enquanto o do Monólito extraiu apenas dez destas famílias de aranhas. A abundância de famílias de aranhas e o índice de diversidade de Shannon (H) foram afetados pelo método de coleta utilizado, sendo os valores destes atributos sempre superiores na NF e inferiores na NPF. A análise de correspondência (AC) demonstrou que existe separação espacial entre as áreas estudadas. Sugere-se que as modificações na abundância de famílias de aranhas de solo sejam provocadas principalmente pelas intervenções antrópicas que as florestas de araucária vêm sofrendo nos últimos anos.

Trap and soil monolith sampled edaphic spiders (arachnida: araneae) in Araucaria angustifolia forest

Forests with Araucaria angustifolia (Bert.) O. Kuntze trees are endangered in Brazil, and information on the diversity of soil spider families associated to these environments is practically inexistent. The present study was set up to evaluate the abundance and diversity of soil spider families in natural and reforested Araucaria forests, impacted or not by fire, and to identify the most efficient method to collect these organisms. The study was conducted in four areas: native forest with predominance of Araucaria (NF); Araucaria reforestation (R); Araucaria reforestation submitted to an accidental fire (RF); and native grass pasture with native Araucaria and submitted to an intense accidental fire (NPF). Considering both sampling methods (Monolith and Pitfall traps), 20 spider families were identified. The pitfall trap method was more effective as it captured 19 out of the 20 recorded families, while the Monolith method extracted only ten spider families. Spider family abundance and Shannon's diversity index (H) were affected by the employed collection method; the values for these attributes were always higher for the NF and lower for the NPF. Correspondence analysis (CA) showed a spatial separation among spider familiy assemblages from the different studied areas. It is suggested that changes in the abundance of soil spider families in Araucaria forests are mainly caused by recurrent human intervention over the last few years.

As florestas com Araucaria angustifolia (Bert.) O. Kuntze estão ameaçadas de extinção no Brasil, e são praticamente inexistentes as informações sobre a diversidade de famílias de aranhas de solo associadas nestes ambientes. O estudo teve o objetivo de avaliar, em florestas com araucária naturais e reflorestadas, impactadas ou não pela queima acidental, a abundância e diversidade de famílias de aranhas, além de identificar o método mais eficiente para coletar estes organismos. O estudo foi conduzido em quatro áreas: floresta nativa com predominância de araucária (NF); reflorestamento de araucária (R); reflorestamento de araucária submetido a incêndio acidental (RF); e pastagem natural com araucárias nativas e ocorrência de incêndio acidental (NPF). Considerando os dois métodos de amostragem (Monólito e armadilhas de solo), foram identificadas 20 famílias de aranhas associadas às áreas. O método das armadilhas de solo foi mais eficiente, capturando 19 das 20 famílias registradas, enquanto o do Monólito extraiu apenas dez destas famílias de aranhas. A abundância de famílias de aranhas e o índice de diversidade de Shannon (H) foram afetados pelo método de coleta utilizado, sendo os valores destes atributos sempre superiores na NF e inferiores na NPF. A análise de correspondência (AC) demonstrou que existe separação espacial entre as áreas estudadas. Sugere-se que as modificações na abundância de famílias de aranhas de solo sejam provocadas principalmente pelas intervenções antrópicas que as florestas de araucária vêm sofrendo nos últimos anos.

Epidemiological aspects of centipede (Scolopendromorphae: Chilopoda) bites registered in Greater S. Paulo, SP, Brazil

A falta de conhecimentos básicos e a benignidade clínica contribuem para que o acidentado por lacraia näo seja encaminhado a um centro de referência para tratamento. Assim, realizou-se estudo para inventariar os acidentes por lacraias na Grande Säo Paulo, Brasil, e apresentar a terapêutica utilizada. Entre 1980 e 1989 investigaram-se os prontuários médicos quanto ao local, mês e horário dos acidentes; sexo, idade e regiäo do corpo atingida, sinais, sintomas e terapêutica. Dos 216 acidentes, 69 por cento ocorreram na Grande Säo Paulo e, em 63 por cento, o agente causal foi identificado. Os gêneros Cryptos, Otostigmus e Scolopendra foram os mais representativos, apresentando em 87 por cento dos casos sintomatologia evidente. Os acidentes predominaram na estaçäo chuivosa quente, período matutino, no sexo feminino entre 21 e 60 anos nas extremidades das mäoes e pés. Somente os picados por Scolopendra e Otostigmus, receberam tratamento terapêutico. O período de reproduçäo na estaçäo chuvosa-quente, associado ao sinantropismo, favorece o aumento dos acidentes em áreas urbanas. Os acidentados por Scolopendra e Otostigmus requerem tratamento terapêutico

Comparative morphological study of the venom glands of the centipede Cryptops iheringi, Otostigmus pradoi and Scolopendra viridicornis

Centipedes are widely distributed over all the continents. As they are well adapted to urban areas they can often cause accidents to humans by injecting venom produced in the glands located inside their maxillipeds. The fine morphology of the centipede venom glands is practically unknown. This present study is the first comparative report on the histology, histochemistry and ultrastructure of the venom glands of the centipede species responsible for the majority of accidents to humans in Brazil: Scolopendra viridicornis, Cryptops iheringi and Otostigmus pradoi. In all species the glands are basically composed of columnar secretory cells radially disposed side by side, individually opening through pores in a central chitinous duct. Each secretory cell is covered by striated muscular fibres. The secretion has the form of small PAS positive granules and large hyaline secretory bromophenol blue positive vacuoles, indicating the presence of neutral polysaccharides and protein. The secretion is conducted through the secretory cell necks to the pores, which open into the central chitinous duct. The results indicate a great similarity both in morphology and primary chemical composition of the venom among the studied species, except for the size of the glands, which is proportional to the body dimensions of each species.