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Richard S Vetter - One of the best experts on this subject based on the ideXlab platform.
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effect of seasonal photoperiod on molting in Loxosceles Reclusa and Loxosceles laeta spiders araneae sicariidae
Journal of Arachnology, 2017Co-Authors: Richard S Vetter, Linda M Penas, Mark S HoddleAbstract:During the winter of 2014–15 in southern California, attempts were made to accelerate immature brown recluse spiders, Loxosceles Reclusa Gertsch & Mulaik, 1940, to maturity for a pest control experiment in early spring. Despite food offerings, spiders stopped molting after October although they were maintained at 25° C and had swollen, well-nourished abdomens. It was surmised that decreased filtered daylight from a paper-covered window might be suppressing molting. Feeding was halted in January 2015; 88 spiderlings were checked weekly for molts. Molting resumed during late March 2015 and continued through May 2015 despite no feedings. To more thoroughly elucidate photoperiod effects on molting, during the week of the September 2015 equinox, three cohorts of 10 immatures of both brown and Chilean recluses, L. laeta (Nicolet, 1849), were exposed to three light regimes: 14:10 L:D, natural, 10:14 L:D. Through November 2015 to late March 2016 for brown recluses, there was no molting in the 10:14 regime, 3 of 10 spiders molted in the natural light regime, and 8 of 10 spiders molted in the 14:10 L:D regime. Additionally, fifteen newly-emerged brown recluse spiderlings split into three cohorts of 5 spiders each in November exhibited more molting in the 14:10 L:D compared to natural and 10:14 L:D light cycles. Chilean recluses showed no differences in molting across the three photoperiod regimes. This species difference may be explained in that brown recluses are native to temperate zones where winters can be fatal; Chilean recluses are tropical where short photoperiods may have little significance for survival.
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seasonality of brown recluse spiders Loxosceles Reclusa submitted by the general public implications for physicians regarding loxoscelism diagnoses
Toxicon, 2011Co-Authors: Richard S VetterAbstract:Many medically important animals exhibit fluctuating seasonal abundance such that risk from envenomation or disease is not constant throughout the year. As indicated by homeowner submissions, brown recluse spiders, Loxosceles Reclusa, show seasonal peaks of activity during summer and paucity in winter. This information should be incorporated as part of the diagnostic algorithm for physicians when considering the probability of loxoscelism in endemic Loxosceles areas especially if a skin lesion occurs when spiders are scarce.
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tracking a medically important spider climate change ecological niche modeling and the brown recluse Loxosceles Reclusa
PLOS ONE, 2011Co-Authors: Erin E. Saupe, Monica Papes, Paul A. Selden, Richard S VetterAbstract:Most spiders use venom to paralyze their prey and are commonly feared for their potential to cause injury to humans. In North America, one species in particular, Loxosceles Reclusa (brown recluse spider, Sicariidae), causes the majority of necrotic wounds induced by the Araneae. However, its distributional limitations are poorly understood and, as a result, medical professionals routinely misdiagnose brown recluse bites outside endemic areas, confusing putative spider bites for other serious conditions. To address the issue of brown recluse distribution, we employ ecological niche modeling to investigate the present and future distributional potential of this species. We delineate range boundaries and demonstrate that under future climate change scenarios, the spider's distribution may expand northward, invading previously unaffected regions of the USA. At present, the spider's range is centered in the USA, from Kansas east to Kentucky and from southern Iowa south to Louisiana. Newly influenced areas may include parts of Nebraska, Minnesota, Wisconsin, Michigan, South Dakota, Ohio, and Pennsylvania. These results illustrate a potential negative consequence of climate change on humans and will aid medical professionals in proper bite identification/treatment, potentially reducing bite misdiagnoses.
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periodicity of molting and resumption of post molt feeding in the brown recluse spider Loxosceles Reclusa araneae sicariidae
Journal of the Kansas Entomological Society, 2010Co-Authors: Richard S Vetter, Michael K RustAbstract:The periodicity of molting and resumption of feeding after molting was investigated in the brown recluse spider, Loxosceles Reclusa Gertsch and Mulaik (Sicariidae). Spiders molted almost every hour of the day but there was a tendency to molt more frequently between 8 A.M. and 1 A.M. Spiderlings resumed feeding after 20 hrs post-molt with feeding occuring more frequently around the 43rd hour and well-established after 48 hrs. The brown recluse spider, Loxosceles Reclusa Gertsch and Mulaik (Sicariidae), is one of the best known spiders in North America, being familiar outside of the arachnological world due to its ability to cause necrotic skin lesions and the propensity of humans to exaggerate this capability. Even though the toxicological aspects of its venom and the medical consequences that ensue are well researched, there is comparatively little information regarding aspects of its life history. Molting in arthropods is a period of extreme change. In spiders, a few days before molting, the legs darken as new setae become evident under the old cuticle (Peck and Whitcomb, 1970; Foelix, 1996) so the onset of molting is obvious. Feeding ceases and does not resume until some degree of exoskeletal hardening occurs. Molting can consume a significant amount of energy. In six spider species studied by Celerier (1986) (theraphosid, four lycosids, ctenid), exuvia production represented 5 to 16% of the growth production for the entire post-embryonic development . Various developmental life history traits in Loxosceles spiders have been documented. The length of individual instars, time from egg to maturity, and overall longevity have been rigorously investigated for L. Reclusa (Hite et al., 1966; Horner and Stewart, 1967), L. laeta (Nicolet) (Galiano, 1967), L. gaucho Gertsch (Rinaldi et al., 1997), L. hirsuta Mello-Leitao (Fischer and da Silva, 2001) and L. intermedia Mello-Leitao (Fischer and Vasconcellos-Neto, 2005). However, other aspects, such as molting periodicity and resumption of feeding post-molt in Loxosceles spiders, have not been researched to our knowledge and, hence, we present our research herein.
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influence of spider silk on refugia preferences of the recluse spiders Loxosceles Reclusa and Loxosceles laeta araneae sicariidae
Journal of Economic Entomology, 2010Co-Authors: Richard S Vetter, Michael K RustAbstract:In a previous experimental study, recluse spiders Loxosceles Reclusa Gertsch and Mulaik and Loxosceles laeta (Nicolet) (Araneae: Sicariidae) preferred small cardboard refugia covered with conspecific silk compared with never-occupied refugia. Herein, we investigated some factors that might be responsible for this preference using similar cardboard refugia. When the two Loxosceles species were given choices between refugia previously occupied by their own and by the congeneric species, neither showed a species-specific preference; however, each chose refugia coated with conspecific silk rather than those previously inhabited by a distantly related cribellate spider, Metaltella simoni (Keyserling). When L. laeta spiders were offered refugia that were freshly removed from silk donors compared with heated, aged refugia from the same silk donor, older refugia were preferred. Solvent extracts of L. laeta silk were chosen approximately as often as control refugia when a range of solvents (methylene chloride:methanol, water, and hexane) were used. However, when acetone was used on similar silk, there was a statistical preference for the control, indicating that there might be a mildly repellent aspect to acetone-washed silk. Considering the inability to show attraction to chemical aspects of fresh silk, it seems that physical attributes may be more important for selection and that there might be repellency to silk of a recently vacated spider. These findings are discussed in regard to pest management strategies to control recluse spiders.
Jamel S. Sandidge - One of the best experts on this subject based on the ideXlab platform.
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Predation by cosmopolitan spiders upon the medically significant pest species Loxosceles Reclusa (Araneae: Sicariidae): limited possibilities for biological control.
Journal of Economic Entomology, 2004Co-Authors: Jamel S. SandidgeAbstract:Interspecific predation of three cosmopolitan house spiders, Achearanea tepidariorum (Kock 1841) (Theridiidae), Steotoda triangulosa (Walckenaer 1802) (Theridiidae), and Pholcus phalangioides (Doleschall 1859) (Pholcidae), and the medically significant brown recluse spider, Loxosceles Reclusa (Sicariidae) were examined to evaluate transitive predatory relationships and to explore the potential use of cosmopolitan spiders as effective biological control agents on L. Reclusa. Fifty houses from northeastern Kansas were visually inspected from May to December 2002 for cosmopolitan spiders and L. Reclusa. In 25 houses, insect monitoring traps were used to sample spider diversity and abundance. The remaining 25 houses were monitored to examine intraguild predation and spider behavior. If cosmopolitan spiders have the ability to regulate or decrease L. Reclusa populations, houses with large cosmopolitan spider populations are expected to have significantly fewer L. Reclusa than houses without cosmopolitan spiders. Predation and/or evidence of predation by all three cosmopolitan spiders on L. Reclusa was detected in 68% of houses. Spearman's rank correlation analysis showed overall positive relationships between population densities of cosmopolitan spiders and L. Reclusa. When evaluated independently, the presence of both A. tepidariorum and S. triangulosa showed negative, yet nonsignificant, relationships with L. Reclusa densities, whereas P. phalangioides showed a positive nonsignificant relationship. Although statistical tests showed a decrease in L. Reclusa population densities with increased population densities of two cosmopolitan species, alluding to a potential beneficial interaction for biological control, observations of spider behavior, web positioning (niche partitioning), and predation showed little possibility of biological control capabilities.
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Scavenging by brown recluse spiders
Nature, 2003Co-Authors: Jamel S. SandidgeAbstract:The brown recluse spider ( Loxosceles Reclusa ) is a threat to humans and establishes huge populations in urban habitats throughout central North America^ 1 , 2 — more than 2,000 of these spiders were recorded in a single house in Kansas^ 3 . What do these spiders eat in order to build and maintain such numbers? Here I combine laboratory prey-choice experiments with observations of the behaviour of L. Reclusa in houses to show that this spider prefers dead, scavenged prey over live prey. This finding may explain how immense populations of these spiders can flourish even in adverse conditions.
Jeff R Whitworth - One of the best experts on this subject based on the ideXlab platform.
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essential oils as an alternative to conventional pesticides for managing brown recluse spiders Loxosceles Reclusa araneae sicariidae
Journal of the Kansas Entomological Society, 2019Co-Authors: Robert Ewing, Holly N Davis, Breta L Alstrom, Chloe E Albin, Ashley M Kragelund, Jeff R WhitworthAbstract:There are several species of spiders in the midwestern United States that cohabit with humans, but probably the most concerning is the brown recluse spider, Loxosceles Reclusa, (Araneae: Sicariidae) because of the potential for a venomous bite. Thus, managing the brown recluse spider is a continuous endeavor. Essential oils (EOs), i.e. specific plant extracts, have often been used to control or deter other arthropods and pests. In this study, several EOs were selected to test their effectiveness as alternatives to synthetic pesticides for L. Reclusa control. Spiders were exposed to EOs by direct contact or as a fumigant (inhalation) treatment for 24 h, and mortality was recorded. Physical contact with the oils resulted in the greatest mortality, with wintergreen, peppermint and lavender to a lesser extent, showing potential for L. Reclusa control. Mortality attributed to lemon, lemongrass or wild orange was too low to provide effective reduction of L. Reclusa populations. Fumigants (inhalation) caused less mortality than contact treatments, never resulting in more than 20%. Two EOs, wintergreen and peppermint, demonstrated effective toxicity to L. Reclusa and may have potential as alternatives to synthetic pesticides for this pest, warranting further investigation.
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the impact of scavenging versus predation on weight change and survival of the brown recluse spider Loxosceles Reclusa araneae sicariidae
Journal of the Kansas Entomological Society, 2019Co-Authors: Robert Ewing, Holly N Davis, Breta L Alstrom, Chloe E Albin, Jeff R WhitworthAbstract:Studies were conducted to determine if predation versus scavenging versus scavenging on insecticide-killed prey affected brown recluse spiders, Loxosceles Reclusa. Indicators of possible effects were measured by weight change and survival. Live house crickets, Acheta domesticus, used as prey, were exposed to one of four treatments: live (untreated control), Spinosad or pyrethroid insecticide treated surface, or freeze-killed (scavenging control) and made available to spiders for twenty-four hours once/week for eight weeks. Spiders fed pyrethroid-killed crickets had significantly lower survival than did spiders utilizing crickets exposed to all other treatments. L. Reclusa had significantly greater weight gain feeding as predators than as scavengers.
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residual effect of insecticide treatment plus use of sticky traps on brown recluse spiders araneae sicariidae on two surfaces
Journal of the Kansas Entomological Society, 2015Co-Authors: Holly N Schwarting, Jeff R WhitworthAbstract:Abstract There is a need for safe and consistent management of the brown recluse spider, Loxosceles Reclusa Gertsch & Mulaik, a toxic spider found in homes throughout Kansas and the south and central United States. This study examined the efficacy of two general-use insecticides with brown recluse on their labels, .05% bifenthrin with 0.0125% zeta-cypermethrin (Insecticide 1), and 0.03% lambda-cyhalothrin (Insecticide 2) against the brown recluse spider at three times post-treatment, 1, 24, and 96 hr, and on two substrates, carpet and tile. This study also evaluated the efficacy of these insecticides on spiders exposed for three lengths of time, 0.5, 1, and 30 min on each substrate. Results indicate that Insecticide 2 had better overall residual efficacy than Insecticide 1. In addition, in one experiment efficacy was better when the spiders were exposed on tile surfaces. Residual efficacy for Insecticide 2 was greater one and 24 hr after application but decreased at 96 hr. The efficacy of Insecticide 1 wa...
Collis R Geren - One of the best experts on this subject based on the ideXlab platform.
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sphingomyelinase d activity of brown recluse spider Loxosceles Reclusa venom as studied by 31p nmr effects on the time course of sphingomyelin hydrolysis
Toxicon, 1998Co-Authors: Michael L Merchant, J F Hinton, Collis R GerenAbstract:Abstract M. L. Merchant, J. F. Hinton and C. R. Geren. Sphingomyelinase D activity of brown recluse spider (Loxosceles Reclusa) venom as studied by 31P-NMR: effects on the time-course of sphingomyelin hydrolysis. Toxicon 36, 537–545, 1998.—The time-course for the hydrolysis of the D linkage of chicken egg yolk sphingomyelin in a Triton X-100 mixed micelle and of lysophosphotidylcholine micelles, as catalyzed by brown recluse spider venom and brown recluse spider toxin, was followed by phosphorous-31 nuclear magnetic resonance spectroscopy. The overall rate of hydrolysis of sphingomyelin in mixed micelles was found to be an order of magnitude faster than the hydrolysis of lysophosphotidylcholine. Incorporation of lysophosphotidylcholine into mixed micelles with Triton X-100 inhibited the lipase activity of brown recluse spider venom and brown recluse spider venom toxin. The effects of increased rates of overall reaction were observed with increased temperature and also with decreased ionic strength. The presence of divalent calcium ions was found to be necessary for hydrolytic activity, but only in catalytic amounts (less than 1 mM).
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effect of hyperbaric oxygen on sphingomyelinase d activity of brown recluse spider Loxosceles Reclusa venom as studied by 31p nuclear magnetic resonance spectroscopy
American Journal of Tropical Medicine and Hygiene, 1997Co-Authors: Michael L Merchant, J F Hinton, Collis R GerenAbstract:Hyperbaric oxygen (HBO) has been reported by some to be therapeutic for necrotic lesions induced by the venom of the brown recluse spider, Loxosceles Reclusa. Others have reported no efficacy for this treatment. In this study, the effect of high pressure oxygen on an enzymatic activity of the toxin of this venom is reported. The time course for the hydrolysis of the phosphocholine ester bond of chicken egg yolk sphingomyelin, as catalyzed by brown recluse spider venom (BRSV) and venom treated with extended HBO (12 hr at 10 atmospheres), was followed by phosphorus-31 nuclear magnetic resonance spectroscopy. The venom and HBO-pretreated venom demonstrated sphingomyelinase D activity. Phospholipase C activity was not detected. The sphingomyelinase D activity of BRSV in three separate experiments was not altered by HBO. The HBO-pretreated venom, in all cases, did not exhibit an altered time course in the overall hydrolysis of the D linkage of sphingomyelin.
Kenneth L Cramer - One of the best experts on this subject based on the ideXlab platform.
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survival abundance and movement of a synanthropic population of the brown recluse spider Loxosceles Reclusa araneae sicariidae
Journal of Arachnology, 2018Co-Authors: Kenneth L Cramer, Eric T HilemanAbstract:We conducted a two-year mark-recapture study of a synanthropic population of the brown recluse spider Loxosceles Reclusa Gertsch & Mulaik, 1940 in northwestern Illinois. We used joint live encounter and dead recovery models to estimate adult survival, recapture, and dead recovery probabilities. To estimate adult abundance, we used full-likelihood closed-population models. Monthly survival was constant between sexes (0.73, 95% CI = 0.66–0.78), but males were less likely to be recaptured and an additive effect of time revealed highest recapture probabilities in September. The probability of recovering a marked adult that died during the study was 0.13 (95% CI = 0.07–0.24). Average life expectancy for adults was 94 days, much lower than in prior laboratory studies. Causes of observed mortality were predation by conspecifics and cobweb spiders (Parasteatoda tepidariorum (C.L. Koch, 1841)) or undetermined. A likely source of mortality for this sit-and-wait predator is starvation. Model averaging of full likelihood closed-population models resulted in adult abundance estimates that were similar between males (28, 95% CI = 20–63) and females (28, 95% CI = 26–38). However, the total population of adults including those hidden in harborage (boxes, furniture, crevices etc.) was undoubtedly much higher. Based on count data, immature spiders were as abundant as adults early in the year, gradually increasing to a peak three times greater by mid-summer. Male spiders moved longer distances than females and were less likely to exhibit site fidelity. The average tenure of a female at a specific site was nearly 8 days.
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activity patterns of a synanthropic population of the brown recluse spider Loxosceles Reclusa araneae sicariidae with observations on feeding and mating
Journal of Arachnology, 2015Co-Authors: Kenneth L CramerAbstract:Abstract I recorded diel and seasonal activity patterns and behavior of the brown recluse spider, Loxosceles Reclusa Gertsch & Mulaik 1940 in a free-ranging synanthropic population in northwestern Illinois. Recluse spiders are sit-and-wait predators that spend 85–90% of their nocturnal activity sitting motionless on a small network of silk they use for prey detection. Time not spent waiting for prey is typically occupied maintaining the web by laying down new strands of silk. Feeding and sexual behavior constitute a minute, but critical, portion of daily activity. Recluses were more active at night, but some were active during the day, especially in darker areas of the garage. Activity was relatively constant during the nocturnal hours. Recluse spiders became active in early to mid-May and ceased in mid-October. Beyond this, there was no consistent pattern observed in activity through these months. Sexual encounters were typically brief and similar to behavior reported in prior lab studies. Agonism was ra...
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cold temperature tolerance and distribution of the brown recluse spider Loxosceles Reclusa araneae sicariidae in illinois
Journal of Arachnology, 2008Co-Authors: Kenneth L Cramer, Alex V MaywrightAbstract:Abstract Although the temperatures at which the brown recluse spider (Loxosceles Reclusa) is active have been described, no work has been done on lethal thermal limits that may influence the distribution of this medically important species. We tested the cold tolerance of L. Reclusa at temperatures ranging from 3° C to −14° C. First, we tested spiders over brief 4-h exposures to a test temperature. Second, we tested spider tolerance to long-term, 30-da exposures to constant, low temperatures to simulate overwintering conditions. We also recorded temperatures beneath the plant litter layer and compared these to ambient surface air temperatures to estimate the effect of litter insulation. We then used the regression of ambient temperature to litter temperature to predict isotherms of litter retreats in Illinois during January, the month of lowest mean winter temperatures. Using the cold temperature lethal limits we found in the lab, we predicted a theoretical distribution of L. Reclusa based solely on tempe...
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are brown recluse spiders Loxosceles Reclusa araneae sicariidae scavengers the influence of predator satiation prey size and prey quality
Journal of Arachnology, 2008Co-Authors: Kenneth L CramerAbstract:Abstract I examined prey choice of the brown recluse spider (Loxosceles Reclusa Gertsch & Mulaik 1940) with reference to unusual scavenging behavior originally reported by Sandidge (2003). Because scavenging is an unexpected behavior in normally predatory spiders, I hypothesized that special circumstances must converge for the brown recluse to prefer dead prey over live prey. I offered crickets (Acheta domesticus) to brown recluses in several choice experiments. I varied predator satiation (spiders not fed for two or four weeks), prey size (small or large), and prey quality (live, fresh dead, dead 1–2 days, 1 week or 1 month). Overall, recluses preferred live prey over dead, but their choice was influenced by all three variables. Recluses were more likely to scavenge when presented with large live prey paired with dead prey of equal size than when presented with small live and dead prey. Spiders that had fed recently were more likely to scavenge. Finally, recluses preferred dead prey that were freshly kil...
