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Richard S. Vetter - One of the best experts on this subject based on the ideXlab platform.
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Black widow spiders, Latrodectus spp. (Araneae: Theridiidae), and other spiders feeding on mammals
Journal of Arachnology, 2018Co-Authors: Martin Nyffeler, Richard S. VetterAbstract:Abstract A survey of reports on spiders preying on small, non-flying mammals (i.e., mice, deer mice, voles, rats, heteromyid rodents, shrews) published in the literature and in the social media yielded a total of 42 naturally occurring incidents. Spiders from five families (Agelenidae, Ctenidae, Sparassidae, Theraphosidae, and Theridiidae) were reported capturing small mammals under natural conditions. Additionally, spiders from four more families (Atracidae, Lycosidae, Pisauridae, and Porrhothelidae) are known to kill small mammals in captivity. Approximately 80% of the reported incidents were attributable to theridiid spiders, especially the Australian redback spider (Latrodectus hasselti Thorell, 1870) and three species of North American widow spiders (Latrodectus geometricus C.L. Koch, 1841, Latrodectus hesperus Chamberlin & Ivie, 1935, and Latrodectus mactans (Fabricius, 1775)) that have been shown to be expert mouse-catchers. The success of widow spiders in subduing small mammals can be explained by...
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efficacy of several pesticide products on brown widow spider araneae theridiidae egg sacs and their penetration through the egg sac silk
Journal of Economic Entomology, 2016Co-Authors: Richard S. Vetter, Cheryl Y Hayashi, Jacob Tarango, Kathleen Campbell, Christine Tham, Dong-hwan ChoeAbstract:Information on pesticide effects on spiders is less common than for insects; similar information for spider egg sacs is scarcer in the open literature. Spider egg sacs are typically covered with a protective silk layer. When pesticides are directly applied to egg sacs, the silk might prevent active ingredients from reaching the eggs, blocking their insecticidal effect. We investigated the impact of six water-based pesticide sprays and four oil-based aerosol products against egg sacs of brown widow spiders, Latrodectus geometricus C. L. Koch. All water-based spray products except one failed to provide significant mortality to egg sacs, resulting in successful spiderling emergence from treated egg sacs at a similar rate to untreated egg sacs. In contrast to water-based sprays, oil-based aerosols provided almost complete control, with 94–100% prevention of spiderling emergence. Penetration studies using colored pesticide products indicated that oil-based aerosols were significantly more effective in penetrating egg sac silk than were the water-based sprays, delivering the active ingredients on most (>99%) of the eggs inside the sac. The ability of pesticides to penetrate spider egg sac silk and deliver lethal doses of active ingredients to the eggs is discussed in relation to the chemical nature of egg sac silk proteins. Our study suggests that pest management procedures primarily relying on perimeter application of water-based sprays might not provide satisfactory control of brown widow spider eggs. Determination of the most effective active ingredients and carrier characteristics warrant further research to provide more effective control options for spider egg sacs.
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Laboratory refugia preferences of the brown widow spider, Latrodectus geometricus (Araneae: Theridiidae)
Journal of Arachnology, 2016Co-Authors: Richard S. Vetter, Linda M. Penas, Mark S. HoddleAbstract:During collecting episodes in urban southern California, brown widow spiders, Latrodectus geometricus C. L. Koch, 1841, were observed to reside most often in specific locations such as acute angles within patio furniture or on the underside of railings. In this laboratory study, we tested several variables to determine which factors brown widow females may use for web site selection. All tests were conducted with corrugated cardboard refugia in enclosed dome-shaped insect cages. Brown widows were found to significantly prefer: 1) 30o angles compared to 60o or 90o angles, 2) cavities of 75 and 100 mm depth compared to 25 or 50 mm depth, 3) cavities lined with single-faced corrugated cardboard compared to smooth surfaces, and 4) refuges that had previously housed a brown widow compared to similar but previously unoccupied refugia. These data provide unusually detailed information about microhabitat selection by an urban pest, with possible implications for the pest control industry for eradication or for home owners to avoid envenomations.
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establishment of the brown widow spider araneae theridiidae and infestation of its egg sacs by a parasitoid philolema latrodecti hymenoptera eurytomidae in french polynesia and the cook islands
Journal of Medical Entomology, 2015Co-Authors: Jerome Marie, Richard S. VetterAbstract:This paper presents two newly established species for French Polynesia: the invasive brown widow spider, Latrodectus geometricus C. L. Koch, and its potential biocontrol agent, the parasitoid wasp, Philolema latrodecti (Fullaway). The brown widow spider was recorded from the island of Moorea in 2006 and, since that discovery, the occurrence of this species has expanded to two of the five archipelagos of French Polynesia including the main island of Tahiti and four of the Cook Islands. Although the tropical climate contributes to the establishment of L. geometricus, a biotic factor, P. latrodecti, may restrain population from demographic explosion. This eurytomid wasp is present in French Polynesia and is a parasitoid that has been used in biological control of the southern black widow Latrodectus mactans (F.) in Hawaii. This wasp could become a significant limiting factor for L. geometricus distribution on these islands, as it was found in 31% of the Tahitian brown widow spider egg sacs that were dissected. However, thus far, the wasp was only found on Tahiti in association with the brown widow spider. Although the brown widow is generally considered to be less toxic than its black widow relatives, it remains of medical concern in French Polynesia because reactions to its bites can, at times, be severe. The spider remains of public concern because it is a novel species; it has the word widow in its name and dark morphs are mistaken as black widows.
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Exposure of Brown Recluse and Brown Widow Spiders (Araneae: Sicariidae, Theridiidae) to a Commercial Sulfuryl Fluoride Fumigation
Journal of economic entomology, 2014Co-Authors: Richard S. Vetter, Mark S. Hoddle, Dong-hwan Choe, Ellen M. ThomsAbstract:The body of pesticide research on spiders is sparse with most studies using topical or residual applications to assess efficacy. Data on the effects of fumigation on spider survivorship are scarce in the scientific literature. In this study, we exposed adult male and female brown recluse spiders, Loxosceles reclusa Gertsch & Mulaik, and female brown widow spiders, Latrodectus geometricus C. L. Koch, to a commercial fumigation event using sulfuryl fluoride directed at termite control. General consensus from the pest control industry is that fumigation is not always effective for control of spiders for a variety of reasons, including insufficient fumigant dosage, particularly, for contents of egg sacs that require a higher fumigant dosage for control. We demonstrated that a sulfuryl fluoride fumigation with an accumulated dosage of 162 oz-h per 1,000 ft(3) at 21°C over 25 h (≈1.7 × the drywood termite dosage) directed at termites was sufficient to kill adult brown recluse and brown widow spiders. The effectiveness of commercial fumigation practices to control spiders, and particularly their egg sacs, warrants further study.
Barrantes Montero Gilbert - One of the best experts on this subject based on the ideXlab platform.
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Latrodectism in Costa Rica
2017Co-Authors: Barrantes Montero Gilbert, Valerio Pizarro RaquelAbstract:Se reporta un accidente causado por la araña Latrodectus geometricus, incluida en el grupo conocido como “viudas negras”, en Costa Rica. El accidente le ocurrió a una mujer de 27 años vecina de la ciudad de Cartago, en su casa de habitación. Los síntomas mostrados cursaron la siguiente secuencia: dolor intenso en el área del piquete, enrojecimiento y aumento en la temperatura al tacto alrededor de ese punto, ampliación del área del dolor, sudoración, dolor de espalda, arritmia, taquicardia y aumento de la presión arterial. Los síntomas mostrados en este caso son muy similares a los descritos por personas picadas por la misma u otras especies de viudas negras en Suramérica y Centroamérica.We here report a case of human lactrodectism in Costa Rica, caused by the spider Latrodectus geometricus, included in the group known as “black widows”. A 27 year-old woman was bitten by a Brown Widow spider in her home in Cartago city. She showed a moderately severe case with the following sequence of symptoms: an acute, intense local pain begins just after being bitten, and this irradiates to the entire affected limb, redness, increase in temperature around the bitten area, sweating and backache. At the cardiovascular level, she showed tachycardia and hypertension. The symptoms showed in this case are quite similar to those cases described for the Brown Widow spider and for other Black Widow spiders, in Central and South America.UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí
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La viuda negra en Costa Rica: Información general
Biocenosis, 2016Co-Authors: Barrantes Montero GilbertAbstract:La viuda café (Latrodectus geometricus) ha sido probablemente introducida a América desde la región mediterránea de África. Desde su llegada a Costa Rica, esta especie ha expandido su distribución rápidamente colonizando prácticamente todas las zonas urbanas y sub-urbanas del Valle Central, hasta una elevación de 1600 m sobre el nivel del mar. La viuda café construye telas tridimensionales en forma de maraña pegadas a las paredes, bajo puentes, bajo sillas u otros muebles e inclusive dentro de las casas. Esta especie ha llegado a ser muy abundante en el país y los encuentros con humanos son frecuentes, debido a su preferencia de hábitat. La viuda café muestra la tendencia de esconderse dentro del refugio de seda que construye en su tela con el menor disturbio (por ejemplo: caída de hojas o humanos que rocen la tela). Por lo tanto, este comportamiento evasivo y la baja toxicidad del veneno de la viuda café comparado con el veneno de otras viudas negras, reduce (pero no elimina) la probabilidad de accidentes a humanos causados por esta especie, a pesar de su gran abundancia
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La viuda negra en Costa Rica: información general
2016Co-Authors: Barrantes Montero GilbertAbstract:La viuda café (Latrodectus geometricus) ha sido probablemente introducida a América desde la región mediterránea de África. Desde su llegada a Costa Rica, esta especie ha expandido su distribución rápidamente colonizando prácticamente todas las zonas urbanas y suburbanas del Valle Central, hasta una elevación de 1600 m sobre el nivel del mar. La viuda café construye telas tridimensionales en forma de maraña pegadas a las paredes, bajo puentes, bajo sillas u otros muebles e inclusive dentro de las casas. Esta especie ha llegado a ser muy abundante en el país y los encuentros con humanos son frecuentes, debido a su preferencia de hábitat. La viuda café muestra la tendencia de esconderse dentro del refugio de seda que construye en su tela con el menor disturbio (por ejemplo: caída de hojas o humanos que rocen la tela). Por lo tanto, este comportamiento evasivo y la baja toxicidad del veneno de la viuda café comparado con el veneno de otras viudas negras, reduce (pero no elimina) la probabilidad de accidentes a humanos causados por esta especie, a pesar de su gran abundancia.The brown widow (Latrodectus geometricus) has likely been introduced to America from the Mediterranean region of Africa. Since its arrival to Costa Rica this species has rapidly expanded its distribution occupying nearly the entire urban and sub-urban areas of the Central Valley, and up to 1600 m a.s.l. The brown widow constructs cobwebs attached to walls, under bridges, under chairs and other pieces of furniture, and even inside houses. This species has become very abundant and encounters with humans are frequent, due to its habitat preferences. The brown widow tends to hide inside the silk retreat of its web at the least disturbance (e.g., a falling leaf or human touching the web). Hence, this evasive behavior and the lower toxicity of the brown widow in comparison with other black widows, reduce (but not eliminate) the probability of accidents by this species to humans, despite its high abundance.UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí
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Incidence of parasitoids and predators on eggs of seven species of Therididae (Araneae)
'Arachology', 2012Co-Authors: Triana Cambronero Emilia, Barrantes Montero Gilbert, Hanson Snortun PaulAbstract:Although many characteristics of the egg sacs of spiders likely evolved to reduce the effect of parasites and predators that attack their eggs, many parasite and predator insects have become specialized on spider eggs. Eggs of six of the seven species of Theridiidae included in this study were attacked by wasp parasites (Baeus achaearaneus, Idris sp., and Comastichus zopheros), and two by the specialized spider egg predator (Neuroptera: Zeugomantispa minuta). The incidence of parasites in the egg sacs varied across species. Parasites attacked more than 60% of the egg sacs of Tidarren sisyphoides and Parasteatoda tepidariorum, but none of the sacs of Latrodectus geometricus. The incidence of parasites in the egg sacs was higher during the dry season for T. sisyphoides, and during the rainy season for P. tepidariorum. The proportion of the eggs parasitized per egg sac varied from 0.09 (± 0.19) in Nesticodes rufipes to 0.50 (± 0.46) in T. sisyphoides. Differences in the biology of parasites, as well as in the structure of spider webs and hábitat preference of spiders, may influence the incidence of parasitism and proportion of eggs parasitized in each egg sac.Vicerrectoría de InvestigaciónUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí
Michael K. Rust - One of the best experts on this subject based on the ideXlab platform.
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predators and parasitoids of egg sacs of the widow spiders Latrodectus geometricus and Latrodectus hesperus araneae theridiidae in southern california
Journal of Arachnology, 2012Co-Authors: Richard S. Vetter, Leonard S. Vincent, Douglas W. R. Danielsen, Kathryn I. Reinker, Daniel E. Clarke, Amelia A. Itnyre, John N. Kabashima, Lindsay Robinson, Michael K. RustAbstract:Abstract The brown widow spider, Latrodectus geometricus C. L. Koch 1841, is non-native to North America and has experienced an explosive range expansion in the first decade of the 21st century. Previously restricted to peninsular Florida, it is now well established in the southeastern United States and southern California. In southern California, brown widow spiders have become ubiquitous around urban homes and are well known to the general public because of their high numbers and distinctive spiked egg sacs. Several insects attack egg sacs of the native western black widow, L. hesperus Chamberlin & Ivie 1935, as either parasitoids or egg predators. We investigated whether and to what degree these insects would attack brown widow egg sacs. We dissected 3,739 brown widow egg sacs finding evidence of the chloropid fly, Pseudogaurax signatus (Loew 1876) in 2.0% and wasp parasitoids in 0.4% of the sacs. For comparison, we also dissected 263 western black widow egg sacs with P. signatus showing a higher level...
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The Prevalence of Brown Widow and Black Widow Spiders (Araneae: Theridiidae) in Urban Southern California
Journal of Medical Entomology, 2012Co-Authors: Richard S. Vetter, Leonard S. Vincent, Douglas W. R. Danielsen, Kathryn I. Reinker, Daniel E. Clarke, Amelia A. Itnyre, John N. Kabashima, Michael K. RustAbstract:The brown widow spider, Latrodectus geometricus C. L. Koch, has become newly established in southern California during the first decade of the 21st century. Brown widows and egg sacs were collected within the urban Los Angeles Basin using timed searches. We also collected and compared the abundance and distribution of the native western black widow spider, Latrodectus hesperus Chamberlin & Ivie, to brown widows. Brown widows were very common around urban structures especially outside homes, in parks, under playground equipment, in plant nurseries and landscaping areas, greatly outnumbering native western black widows, and were very rare or nonexistent in garages, agricultural crops, and natural areas. Western black widows predominated in xeric habitats and were less prevalent around homes. Neither species was found in the living space of homes. In southern California, envenomation risk exists because brown widows are now common in urban areas and the spiders hide where people place their fingers and exert pressure to move objects (e.g., under the curled lip of potted plants, in the recessed handle of plastic trash bins). Nonetheless, brown widow spider bites are less toxic than those of native western black widow spiders and, hence, if they are displacing black widows, overall widow envenomation risk may actually be lower than before brown widow establishment.
Jerome Goddard - One of the best experts on this subject based on the ideXlab platform.
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severe reaction from envenomation by the brown widow spider Latrodectus geometricus araneae theridiidae
Southern Medical Journal, 2008Co-Authors: Jerome Goddard, Stacy Upshaw, David Held, Kerry JohnnsonAbstract:The brown widow, Latrodectus geometricus, is one of five species of Latrodectus in the United States, and is reported to be one of the least dangerous. However, we report a previously healthy patient bitten by a brown widow, resulting in a serious reaction requiring hospitalization. Symptoms included severe pain, cramps, nausea/vomiting, and fasciculations in the pectoral and quadriceps muscles. This report signals a need to re-evaluate previously held ideas that brown widow bites are of minor consequence.
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additions to the known u s distribution of Latrodectus geometricus araneae theridiidae
Journal of Medical Entomology, 2008Co-Authors: K S Brown, J S Necaise, Jerome GoddardAbstract:The range of the brown widow spider Latrodectus geometricus C. L. Koch includes much of Africa and South and Central America. This medically important spider has been recently introduced to Japan, Indonesia, Papua New Guinea, Australia, Hawaii, and California. After the identification of the brown widow spider in New Orleans, LA, and southern Mississippi, surveys in the southeastern United States were conducted from the fall of 2006 through February 2008. We found populations of brown widow spiders in Georgia, Texas, and multiple localities in southeastern Louisiana and Mississippi. In Mississippi, specimens were collected as far north as a county bordering Tennessee. In New Orleans, the brown widow spider has been commonly collected from various locations where human contact is likely.
Douglas W. R. Danielsen - One of the best experts on this subject based on the ideXlab platform.
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natural egg sac clutch size of the brown widow spider Latrodectus geometricus araneae theridiidae in southern california
Bulletin Southern California Academy of Sciences, 2014Co-Authors: Douglas W. R. Danielsen, Leonard S. Vincent, Daniel E. Clarke, Stephen J Valle, Amy A Ansalmo, Richard S. VetterAbstract:The brown widow spider, Latrodectus geometricus C. L. Koch, 1841, is a non-native arachnid that became established in peninsular Florida in the 1930s (Pearson 1936). In the first decade of the 21 century, it rapidly spread through the southeastern United States and southern California (Brown et al. 2008; Vincent et al. 2008; Vetter et al. 2012a) and has become a ubiquitous urban pest species in the Los Angeles Basin and San Diego area (Vetter et al. 2012b). One possible reason for its success lies in its fecundity, as it can produce an egg sac every four days during its earliest ovipositions and averages 22 egg sacs in a lifetime (Bouillon and Lekie 1961). We were interested in documenting the seasonal field egg production of brown widows from June to October to determine whether there is a specific peak and subsequent dropoff in productivity or whether it is fairly consistent throughout the summer season. This provided basic biology information that benefitted research involving insecticide bioassays on brown widow egg sacs (Vetter et al, in prep); knowing the phenology of seasonal clutch size helped determine whether lab-produced egg sacs would be temporally comparable with natural oviposition and, hence, whether pesticides tested on egg sacs would have real world relevance. To determine monthly egg clutch size, brown widow egg sacs were collected during the day from several cities in Orange and Riverside counties, California from June through October 2012. Collections were restricted to urban sites such as around homes, in parks, under playground equipment, etc. as documented favored habitats for this spider (Vetter et al. 2012b). We attempted to collect egg sacs primarily from sites that were occupied by female brown widows as this presumedly increased the chances of collecting sacs with freshly laid eggs. The study was terminated at the end of October because temperatures cool considerably in November in southern California. We did not collect egg sacs for the first seven days of any month in order to more accurately assign sacs with eggs to the correct month of oviposition. At 29uC, brown widow eggs hatch in 9 days. Considering that daily high temperatures in many of our collection locales are typically 35 to 40uC, we felt that this was an acceptable estimate to separate clutch size into monthly cohorts. We also received some sacs in the mail from citizen scientists who participated in previous brown widow studies (Vetter et al. 2012a,b); again, no data from sacs collected and received during the first week of the month were used.
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predators and parasitoids of egg sacs of the widow spiders Latrodectus geometricus and Latrodectus hesperus araneae theridiidae in southern california
Journal of Arachnology, 2012Co-Authors: Richard S. Vetter, Leonard S. Vincent, Douglas W. R. Danielsen, Kathryn I. Reinker, Daniel E. Clarke, Amelia A. Itnyre, John N. Kabashima, Lindsay Robinson, Michael K. RustAbstract:Abstract The brown widow spider, Latrodectus geometricus C. L. Koch 1841, is non-native to North America and has experienced an explosive range expansion in the first decade of the 21st century. Previously restricted to peninsular Florida, it is now well established in the southeastern United States and southern California. In southern California, brown widow spiders have become ubiquitous around urban homes and are well known to the general public because of their high numbers and distinctive spiked egg sacs. Several insects attack egg sacs of the native western black widow, L. hesperus Chamberlin & Ivie 1935, as either parasitoids or egg predators. We investigated whether and to what degree these insects would attack brown widow egg sacs. We dissected 3,739 brown widow egg sacs finding evidence of the chloropid fly, Pseudogaurax signatus (Loew 1876) in 2.0% and wasp parasitoids in 0.4% of the sacs. For comparison, we also dissected 263 western black widow egg sacs with P. signatus showing a higher level...
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The Prevalence of Brown Widow and Black Widow Spiders (Araneae: Theridiidae) in Urban Southern California
Journal of Medical Entomology, 2012Co-Authors: Richard S. Vetter, Leonard S. Vincent, Douglas W. R. Danielsen, Kathryn I. Reinker, Daniel E. Clarke, Amelia A. Itnyre, John N. Kabashima, Michael K. RustAbstract:The brown widow spider, Latrodectus geometricus C. L. Koch, has become newly established in southern California during the first decade of the 21st century. Brown widows and egg sacs were collected within the urban Los Angeles Basin using timed searches. We also collected and compared the abundance and distribution of the native western black widow spider, Latrodectus hesperus Chamberlin & Ivie, to brown widows. Brown widows were very common around urban structures especially outside homes, in parks, under playground equipment, in plant nurseries and landscaping areas, greatly outnumbering native western black widows, and were very rare or nonexistent in garages, agricultural crops, and natural areas. Western black widows predominated in xeric habitats and were less prevalent around homes. Neither species was found in the living space of homes. In southern California, envenomation risk exists because brown widows are now common in urban areas and the spiders hide where people place their fingers and exert pressure to move objects (e.g., under the curled lip of potted plants, in the recessed handle of plastic trash bins). Nonetheless, brown widow spider bites are less toxic than those of native western black widow spiders and, hence, if they are displacing black widows, overall widow envenomation risk may actually be lower than before brown widow establishment.