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PubMed1975

[Basic analysis of the effective system of homing in spider Agelena labyrinthica (Cl.)].

1. The spider Agelena labyrinthica Cl. determined its home direction by integrating the information of each element of the outgoing path to the prey in continuous interaction with the incident light. 2. A vector hypothesis explaining how the direction and the length of the homing track was determined was verified: if the azimuth of the incident light was displaced by 90 degrees as soon as the spider had reached a certain point on the web, the vector of the theoretical course originating from this point was rotated by about 60 degrees. The end point of this rotated vector ("fictitious retreat point") was not only the goal for the homing course from this point, but also for the course originating from any other point of the web. 3. Spiders starting at the fictitious retreat point did not keep straight courses. Their movements were either at random or they were directed in slightly preferred directions caused by the phototactic influence of the previously performed outward course. 4. If the light had been displaced before the spider was lifted from the web, the lifting had no effect on the orientation performance. 5. The mean distance between the points of direction changes and the starting points varied linearly with the mean length of the outward course; therefore these distances were used as an indication for the distance orientation. 6. Contrary to all other formerly published hypotheses on the photomenotactic orientation of arthropods MITTELSTAEDTs' hypothesis about the homing of Agelena, which is similar to my vector hypothesis, is compatible with the data compiled by this investigation.

Animals↗
PubMed1992

Cuticular spinning structures reveal evolutionary relationships in araneomorph spiders.

The present paper reviews the results from the study of spigots, i.e. cuticular spinning structures obtained by the scanning of 52 genera belonging to 28 families of araneomorph spiders. The finding of eight morphologically different forms of these structures being attached to ducts of the pyriform type of silk glands is of fundamental importance for the final conclusions. The comparative observations enable me to create a hypothesis dealing with the existence of several evolutionary lines of spiders, each of which is represented with their own form of spigots. Nevertheless the character of these spigots undoubtedly reflects phylogenetic relationships between the spider taxa. The detection of a special mechanoreceptive field on top of the anterolateral spinnerets increases the knowledge of the functional morphology of the spider's spinning apparatus.

Animals↗
PubMed2005

Severe systemic reaction to Loxosceles reclusa spider bites in a pediatric population.

OBJECTIVE: To report 6 children who had severe systemic reaction after spider bites requiring pediatric intensive care unit admission and to describe their clinical presentation, hospital course, and outcome. METHODS: A retrospective analysis was done to identify patients presenting with brown recluse spider bites. Charts of children admitted to the intensive care unit were reviewed. RESULTS: Six previously healthy African-American children, aged 3 to 15 years, with brown recluse spider bites were admitted to the pediatric intensive care unit. All had fever, jaundice, and evidence of hemolytic anemia. Four of 6 children had hypotension. One child developed mental status changes, acute renal failure secondary to rhabdomyolysis, and hyperkalemia and required emergent hemodialysis. All children fully recovered. CONCLUSION: Although most cases of brown recluse spider bites are benign requiring no intervention, severe systemic reactions may occur in the pediatric population resulting in admission to the pediatric intensive care unit. These systemic reactions may include hemolytic anemia, hypotension, and renal failure.

Adolescent↗
PubMed1989

[Histochemical detection of enzymes in the spinning glands of spiders].

The spider's spinning apparatus equipped with numerous glands of several types appears to be a suitable model for studying tissues which produce large amounts of fibrillar proteins. Heterogeneous glandular system is of special benefit for study of the function of different enzymes taking part both in the synthesis and the degradation of mentioned proteins. It is evident that the activity of the enzyme is dependent not only on the physiologic condition or a certain phase of spider's life cycle, but it is also given by the type of gland, i. e., defined by the structure and properties of protein to be emitted. Histochemical study of enzymes brings some new and more precise views on the spinning apparatus function. Also a participation of individual gland types in some definite spider's life period is so indicated as well as it is convenient for better understanding biologic function of structures performed by spider.

Animals↗
PubMed1979

Inactivation of complement by Loxosceles reclusa spider venom.

Zymosan depletion of serum complement in guinea pigs rendered them highly resistant to lesion by Loxosceles reclusa spider venom. Guinea pigs deficient in C4 of the complement system are as sensitive to the venom as normal guinea pigs. The injection of 35 micrograms of whole recluse venom intradermally into guinea pigs lowered their complement level by 35.7%. Brown recluse spider venom in concentrations as slight as 0.02 micrograms protein/ml can totally inactivate one CH50 of guinea pig complement in vitro. Bee, scorpion, and other spider venoms had no influence on the hemolytic titer of complement. Fractionation of recluse spider venom by Sephadex G-200 filtration separated the complement-inactivating property of the venom into three major regions which could be distinguished on the basis of heat stability as well as size. None was neutralized by antivenom. Polyacrylamide gel electrophoresis of venom resolved the complement inactivators into five fractions. Complement inactivated by whole venom or the Sephadex fractions could be restored to hemolytic activity by supplements of fresh serum but not by heat-inactivated serum, pure C3, pure C5, or C3 and C5 in combination.

Animals↗
PubMed1982

The ionic dependence of black widow spider venom action at the stretch receptor neuron and neuromuscular junction of crustaceans.

The effects of black widow spider venom (BWSV) on the crayfish stretch receptor and the lobster neuromuscular junction were examined. In crayfish stretch receptor neurons, BWSV caused a slight hyperpolarization followed by a large depolarization. The venom-induced depolarization of the stretch receptor was caused by an increase in membrane conductance to Na+ and Ca2+. Black widow spider venom also caused an increase in the frequency of miniature inhibitory postsynaptic potentials recorded in the stretch receptor. The ability of BWSV to increase the frequency of miniature excitatory postsynaptic potentials (MEPSPs) at the lobster neuromuscular junction was dependent on the divalent cation composition of the bathing medium. Ringer solutions containing Ca2+ supported the greatest venom-induced increase in MEPSP frequency, Mg2+ and Mn2+ supported a moderate increase in MEPSP frequency, while Co2+ and Zn2+ blocked this venom effect entirely. Black widow spider venom did not block axonal conduction in lobster walking leg axons or in the axon of the crayfish stretch receptor. The results suggest that in crustaceans, BWSV interacts specifically with membrane of the soma-dendritic region of the stretch receptor and with nerve terminal membrane, causing an increase in Na+ and Ca2+ conductance.

Animals↗
PubMed1978

Effect of concanavalin A on black widow spider venom activity at the neuromuscular junction: implications for mechanisms of venom action.

Concanavalin A (Con A) inhibits black widow spider venom-induced transmitter release at both tissue-cultured and adult neuromuscular junctions and also inhibits the venom-induced destruction of cultured neurites. This inhibitory action is partially or completely prevented by prior treatment with colchicine. Neither colchicine nor Con A interacts significantly with depolarization-induced transmitter release. These results are analogous to those obtained from experiments on lymphocyte surface receptor capping. They suggest that redistribution of neuronal membrane components may be a crucial step in spider venom action. This membrane redistribution appears to be modulated in neurons, as in other cell types, by microtubule-microfilament array. How such a redistribution causes increased transmitter release cannot as yet be specified. Changes in the ionic permeability of sodium and potassium were examined as likely mechanisms. Increased sodium influx (and seondary release of calcium from intracellular stores) cannot be the basis for spider venom action. Increased potassium efflux remains a possibility, but is not consistent with all of the data. Other possible mechanisms are also suggested.

Animals↗
PubMed1995

Quantity and quality of venom released by a spider (Cupiennius salei, Ctenidae).

The amount of venom injected by the spider Cupiennius salei depended on the efficiency of the mechanical defence of the prey species. Spiders were milked for the first venom (i.e. the first microlitre of venom emitted) versus remaining venom, and for venom regenerated from emptied glands. HPLC gel filtration and IEF electrophoresis showed that the protein content of the first venom was only half as compared to that of the remaining venom, and that this was due to a dilution of all proteins. Venom regeneration came in two speeds. The amount of venom was regenerated more rapidly than the protein concentration. Newly regenerated venom as compared to older venom was characterized by a lower concentration of all proteins and by a higher total concentration of free amino acids, whereas histamine and taurine did not follow this trend. K+ concentration and pH remained similar during venom regeneration. Crickets injected with the venoms showed less acute symptoms when the protein concentration was lower, namely with the first venom and with newly regenerated venom. Consequently, a spider which modulates the quantity of venom injected into a prey also directly changes the venom quality. The ecological consequences of this are discussed. This paper also discusses which region of a gland (ampulla, extracellular and intracellular parts of the glandular sac) is involved in the changes of the venom quality.

Amino Acids↗
PubMed2006

Brown recluse spider envenomation.

Brown recluse spider bite is a common diagnosis in almost every state in America. In fact, cases have been reported in areas where the spider has never been seen. A review of medical literature reveals that most current concepts regarding brown recluse spider envenomation are based on supposition. In this article, we attempt to review critically our present understanding of brown recluse bites with a focus on the published evidence.

Animals↗
PubMed2002

Isolation and identification of Clostridium perfringens in the venom and fangs of Loxosceles intermedia (brown spider): enhancement of the dermonecrotic lesion in loxoscelism.

Loxoscelism or the envenoming by the brown spiders (Loxosceles genus spiders), may produce extensive dermonecrosis and hemorrhage at the bite site and, eventually, systemic reactions that may be lethal. Isolation and identification of many different bacteria, among them Clostridium perfringens, of great medical importance due to its involvement in dermonecrotizing and systemic conditions, was carried out from the venomous apparatus (fangs and venom) of spiders obtained directly from nature, through microbiological cultures in aerobic and anaerobic conditions. Working with Loxosceles intermedia venom (alone) and with the venom conjugated with Clostridium perfringens using rabbits as experimental models for dermonecrosis, allowed for the observation that venom and anaerobic bacteria conjugated resulted in a striking increase of the dermonecrotic picture when compared to venom alone, suggesting a role for Clostridium perfringens in the severe dermonecrotic picture of these patients and opening the possibility for the association of antibiotic therapy in treating loxoscelism.

Animals↗
PubMed2006

[Steatoda spider envenomation in southern France].

INTRODUCTION: Cobweb spiders (genus Steatoda) are small species closely related to black widow spiders and their bites can induce envenomation known as steatodism. CASE: A 46-year-old man in the Gard district in southern France was sleeping in his bed when a spider (identification Steatoda triangulosa) bit him. Clinical manifestations included local signs together with systemic neurological symptoms resembling low-grade latrodectism (black widow envenomation). DISCUSSION: This first-recorded case of steatodism in southern France differs in several ways from the classic pattern of latrodectism in Europe: the bite occurred in home during winter and mild symptoms resolved quickly without hospital care. CONCLUSION: In endemic areas (in France the Mediterranean climate zone: Provence, Languedoc and Corsica), steatodism should be considered when low-grade latrodectism is observed.

Animals↗
PubMed2002

A new assay for the detection of Loxosceles species (brown recluse) spider venom.

STUDY OBJECTIVE: Dermal lesions from unrelated arthropod species and medical causes appear similar to Loxosceles species (brown recluse spider) bites. This may result in delayed diagnosis and treatment. We developed a sensitive Loxosceles species venom enzyme-linked immunosorbent assay (ELISA) and characterized the specificity of the assay by evaluating antigenic cross-reactivity from a variety of North American arthropod venoms. METHODS: North American arthropod (14 spiders, 2 scorpions, and 1 bee) venoms were studied. Three venom amounts (diluted in 100 microL of ELISA buffer) were assayed: 16,000 ng, 2,000 ng, and 40 ng. The latter quantity was selected because this is the observed maximum amount of venom we detect when inoculating dermis with amounts likely to be deposited by a spider bite. The larger venom amounts are overwhelming quantities designed to test the limits of the assay for arthropod venom cross-reactivity. Similar amounts of Loxosceles species venom and bovine albumin served as positive and negative controls, respectively. RESULTS: At the lowest amount of venom tested (40 ng), the ELISA detected only the Loxosceles species positive control. When 2,000 ng was assayed, only Scytodes fusca and Kukulcania hibernalis arachnid venoms (in addition to Loxosceles species) cross-reacted to the assay. Finally, at 16,000 ng, the ELISA assay modestly detected Diguetia canities, Heteropoda venatoria, Tegenaria agrestis, Plectreurys tristes, Dolomedes tenebrosus, and Hadrurus arizonensis arachnid venoms. CONCLUSION: Cross-reactivity was observed in 8 of 17 North American arthropod venoms when large venom amounts were assayed with a Loxosceles species ELISA. By using a relevant quantity of venom, 40 ng, the assay was specific for Loxosceles species venom. The venom specificity of the ELISA may allow clinical application in Loxosceles species endemic regions of North America.

Animals↗
PubMed1984

Spider (Latrodectus hesperus) poisoning through the conjunctiva. A case report.

Spider poisoning is usually a result of the direct bite, envenomation through the chelicera, of the spider. Reported is an unusual case in which poisoning occurred through the conjunctiva when a fragment from a smashed black widow spider (Latrodectus hesperus) flew into a patient's eye. In addition to an immediate local reaction involving the periorbital tissues, the patient experienced systemic effects.

Adult↗
PubMed2002

[Poisoning by spiders of Loxosceles genus].

Despite the great number of spiders in the world, only a small group of them is capable of producing death in humans. In Argentina, there are only three of the four genera of spiders considered of high risk to humans: Latrodectus is present in rural areas, Phoneutria is restricted to small regions while Loxosceles is distributed throughout the country. Accidents by Loxosceles represent around 4% of the total number produced by venomous animals in Argentina. The bite is accidental and may produce considerable local necrosis with scar formation and ulcers of slow and difficult healing that may require surgical repair. Some bitten people may suffer from intravascular hemolysis, disseminated coagulation and acute renal insufficiency leading to death. Despite the great number of studies performed on Loxosceles venoms, at present, the physiopathological course of poisoning is not clear and there is not common criteria for its treatment. In this review, biological and epidemiological data of this spider are described as well as the venom composition and the possible participation of its components in the poisoning. These data provide biological and biochemical tools to understand the course of poisoning and to have better criteria for the treatment and prevention of these accidents and their complications.

Animals↗
PubMed2002

A reduced immunization scheme to obtain an experimental anti-Loxosceles laeta ("violinist spider") venom.

Bites by Loxosceles (L.) laeta spiders can produce severe envenomation in humans. The only specific treatment is the early administration of antivenom. The production of anti-Loxosceles antivenom is hampered by the extremely low venom yield by these spiders and by the difficulties in maintaining a large breeder of Loxosceles. We developed an experimental equinum L. laeta antivenom, using as immunogen venom glands homogenates from spiders captured in Argentina. Horses immunized with venom gland homogenate (1.0 mg total protein per horse) by the subcutaneous route were bled after completion of the immunization scheme. Plasma was fractionated by ammonium sulfate precipitation and treated with pepsin to obtain F(ab')2 fragments. The protein composition of the experimental antivenom was assessed by SDS-PAGE, and its immunochemical reactivity was compared with those of other anti-Loxosceles antivenoms available for therapeutic use in Argentina by ELISA and Western blot. The experimental, homologous anti-L. laeta antivenom appeared to be more efficient in neutralizing the lethal potency in mice and the necrotizing activity in rabbits than of the heterologous antivenom.

Animals↗
PubMed2007

Which senses play a role in nonhuman primate food selection? A comparison between squirrel monkeys and spider monkeys.

In order to optimize foraging efficiency and avoid toxicosis, animals must be able to detect, discriminate, and learn about the predictive signals of potential food. Primates are typically regarded as animals that rely mainly on their highly developed visual systems, and little is known about the role that the other senses may play in food selection. It was therefore the aim of the present study to assess which senses are involved in the evaluation of food by two species of New World primates: the squirrel monkey and the spider monkey. To this end, six animals per species were repeatedly presented with both familiar and novel food items, and their behavior was videotaped and analyzed. To obtain a further indication of the relative importance of visual and chemosensory cues, the animals were also presented with familiar food items that were experimentally modified in color, odor, or both color and odor. The results demonstrate that squirrel monkeys and spider monkeys use olfactory, gustatory, and tactile cues in addition to visual information to evaluate novel food, whereas they mainly inspect familiar food items visually prior to consumption. Our findings also show that in both species the use of nonvisual cues decreased rapidly with repeated presentations of novel food, suggesting a fast multimodal learning process. Further, the two species clearly differ in their relative use of nonvisual cues when evaluating novel or modified food, with spider monkeys relying more on olfactory cues than squirrel monkeys, and squirrel monkeys relying more on tactile cues compared to spider monkeys.

Animals↗
PubMed2004

Patterns of behavior across reproductive states of free-ranging female black-handed spider monkeys (Ateles geoffroyi).

Reports on the behavior of spider monkeys (genus Ateles) describe a suite of 5-6 behaviors that are indicative of an estrous female. This study presents hormonal data as an independent measure of reproductive state to determine if these behaviors are associated with any particular reproductive state or stage of the ovarian cycle. Fecal samples collected from 6 free-ranging female black-handed spider monkeys (Ateles geoffroyi) over the course of 11 months were assayed for estrogen (E1C) and progesterone (PdG) metabolites, using an enzyme immunoassay. Behavioral data collected from the same females were analyzed for patterns associated with different reproductive states. A more detailed analysis of behavioral data associated with reproductively cycling periods determined whether each behavior clustered with copulations or a particular phase in the ovarian cycle. Observations of place-sniffing were more frequent for 4 of 5 females when reproductively cycling. Of all copulations observed, 80% occurred when the female participant was reproductively cycling. In addition, the rates of self-clitoral hold and self-clitoral rub behaviors were significantly higher for 2 of 4 and 4 of 5 of females, respectively, when reproductively cycling. No behavior consistently occurred in association with copulations or with any particular phase in the ovarian cycle. Results from this study suggest that the behaviors tested in this paper can provide some information regarding female spider monkey reproductive state (whether or not she is reproductively cycling), but that they are not indicators of estrus in female spider monkeys.

Animals↗
PubMed2006

Raiding parties of male spider monkeys: insights into human warfare?

Raids into neighboring territories may occur for different reasons, including the increase of foraging and mating opportunities directly or indirectly through the killing of neighboring rivals. Lethal raids have been mainly observed in humans and chimpanzees, with raiding males being reported to search purposefully for neighbors. Here we report on the first cases ever witnessed of raiding parties of male spider monkeys, a species expected to show such a behavioral tendency, given its similarity with humans and chimpanzees in critical socio-ecological characteristics, such as fission-fusion social dynamics and male-male bonding. Despite the high degree of arboreality of spider monkeys, all seven witnessed raids involved the males progressing single file on the ground in unusual silence. This is remarkably similar to the behavior of chimpanzees. The circumstances around the raids suggest that factors such as reduced mating opportunities, number of males relative to that in the neighboring community, and the strength of bonds among males could play a role in the timing of such actions. The raids did not appear to be aimed at finding food, whereas there is some indication that they may directly or indirectly increase reproductive opportunities. Although no killing was observed, we cannot exclude the possibility that spider monkey raids may be aimed at harming rivals if a vulnerable individual were encountered. The similarity of spider monkey raids with those of chimpanzees and humans supports the notion that lethal raiding is a convergent response to similar socio-ecological conditions.

Aggression↗