Abstract. We describe two new Nesticus Thorell, 1869 from Walker County, Georgia, USA. Nesticus lula sp. nov. is known from two caves on the eastern edge of Lookout Mountain and N. cressleri sp. nov. is known from three caves on Pigeon Mountain. Morphological and molecular evidence indicates the distinctiveness of both species when compared to other Nesticus from the southern Appalachians. Nesticus lula has reduced eyes and N. cressleri is eyeless. Both species are of conservation concern, as they are known from only a handful of sites spanning extremely limited ranges. This work contributes to our understanding of cave biodiversity in Georgia and of the Nesticus radiation in the southern Appalachians.
{"title":"Two new Nesticus Thorell, 1869 (Araneae: Nesticidae) from caves in northwest Georgia, USA","authors":"K. Zigler, M. Milne","doi":"10.1636/JoA-S-21-035","DOIUrl":"https://doi.org/10.1636/JoA-S-21-035","url":null,"abstract":"Abstract. We describe two new Nesticus Thorell, 1869 from Walker County, Georgia, USA. Nesticus lula sp. nov. is known from two caves on the eastern edge of Lookout Mountain and N. cressleri sp. nov. is known from three caves on Pigeon Mountain. Morphological and molecular evidence indicates the distinctiveness of both species when compared to other Nesticus from the southern Appalachians. Nesticus lula has reduced eyes and N. cressleri is eyeless. Both species are of conservation concern, as they are known from only a handful of sites spanning extremely limited ranges. This work contributes to our understanding of cave biodiversity in Georgia and of the Nesticus radiation in the southern Appalachians.","PeriodicalId":51076,"journal":{"name":"Journal of Arachnology","volume":"50 1","pages":"292 - 300"},"PeriodicalIF":1.0,"publicationDate":"2022-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42004797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Uiterwaal, N. Graham, Taylor Steiner, T. B. Corey
Abstract. Metabolism powers all of life's processes, making it fundamental to understanding organisms in nature. For many arachnids, however, we do not have direct measurements of either metabolic rate or the relationship between metabolic rate and body size (i.e., allometric scaling, an important determinant of metabolic rate). Here, we present the first measurements of metabolic rate and allometric scaling in a stridulating spined micrathena spider, Micrathena gracilis (Walckenaer, 1805). Since intraspecific variation in metabolic rate may provide insights into variation in energetically costly behaviors, we additionally explore the link between stridulation and metabolism in M. gracilis. Our data suggests a link between stridulatory behavior and allometric scaling, such that increased stridulation is associated with a weaker connection between body mass and metabolic rate. We discuss how links between energetics, expression of behavior, and body size inform our understanding of trait variation in these spiders.
{"title":"Metabolism in Micrathena gracilis, a stridulating orb-weaver (Araneae: Araneidae)","authors":"S. Uiterwaal, N. Graham, Taylor Steiner, T. B. Corey","doi":"10.1636/JoA-S-21-055","DOIUrl":"https://doi.org/10.1636/JoA-S-21-055","url":null,"abstract":"Abstract. Metabolism powers all of life's processes, making it fundamental to understanding organisms in nature. For many arachnids, however, we do not have direct measurements of either metabolic rate or the relationship between metabolic rate and body size (i.e., allometric scaling, an important determinant of metabolic rate). Here, we present the first measurements of metabolic rate and allometric scaling in a stridulating spined micrathena spider, Micrathena gracilis (Walckenaer, 1805). Since intraspecific variation in metabolic rate may provide insights into variation in energetically costly behaviors, we additionally explore the link between stridulation and metabolism in M. gracilis. Our data suggests a link between stridulatory behavior and allometric scaling, such that increased stridulation is associated with a weaker connection between body mass and metabolic rate. We discuss how links between energetics, expression of behavior, and body size inform our understanding of trait variation in these spiders.","PeriodicalId":51076,"journal":{"name":"Journal of Arachnology","volume":"50 1","pages":"288 - 291"},"PeriodicalIF":1.0,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42998599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Catherine Wu, Chaiti Bhagawat, Modan R. Goldman, Nihal A. Punjabi, D. Shier, Roxana P. Arauco-Aliaga, G. Grether
Abstract. Group-living spiders are rare, and can be divided into multiple subcategories based on their tolerance of group mates. While social spiders are cooperative, colonial spiders are often antagonistic towards conspecifics. We examined colony dynamics in a colonial species, Philoponella republicana (Simon, 1891), focusing on aggressive behaviors to further understand this understudied species. We studied whether web region, sex ratio, web size, or spider size affected aggression. We also tested whether colony members discriminate against conspecific intruders, since this behavior, known as group closure, is prevalent in many other group-living animals but had not yet been tested in colonial spiders. Colony mates were often aggressive due to competition for limited resources, such as mates and orb webs, yet several characteristics of this species may reduce these competitive forces. First, female-biased secondary sex ratios appear to reduce male-male and female-male competition. Moreover, although some individuals defended orb webs, other areas in the communal web were not defended. Philoponella republicana also did not exhibit group closure. Our results further confirm that aggression between males decreases in colonies with more female-biased secondary sex ratios, and larger individuals correlate with a higher frequency of aggressive interactions. Moreover, we raise new questions concerning the evolutionary pressures that shape coloniality in spiders.
{"title":"Aggression in a western Amazonian colonial spider, Philoponella republicana (Araneae: Uloboridae)","authors":"Catherine Wu, Chaiti Bhagawat, Modan R. Goldman, Nihal A. Punjabi, D. Shier, Roxana P. Arauco-Aliaga, G. Grether","doi":"10.1636/JoA-S-20-093","DOIUrl":"https://doi.org/10.1636/JoA-S-20-093","url":null,"abstract":"Abstract. Group-living spiders are rare, and can be divided into multiple subcategories based on their tolerance of group mates. While social spiders are cooperative, colonial spiders are often antagonistic towards conspecifics. We examined colony dynamics in a colonial species, Philoponella republicana (Simon, 1891), focusing on aggressive behaviors to further understand this understudied species. We studied whether web region, sex ratio, web size, or spider size affected aggression. We also tested whether colony members discriminate against conspecific intruders, since this behavior, known as group closure, is prevalent in many other group-living animals but had not yet been tested in colonial spiders. Colony mates were often aggressive due to competition for limited resources, such as mates and orb webs, yet several characteristics of this species may reduce these competitive forces. First, female-biased secondary sex ratios appear to reduce male-male and female-male competition. Moreover, although some individuals defended orb webs, other areas in the communal web were not defended. Philoponella republicana also did not exhibit group closure. Our results further confirm that aggression between males decreases in colonies with more female-biased secondary sex ratios, and larger individuals correlate with a higher frequency of aggressive interactions. Moreover, we raise new questions concerning the evolutionary pressures that shape coloniality in spiders.","PeriodicalId":51076,"journal":{"name":"Journal of Arachnology","volume":"50 1","pages":"277 - 287"},"PeriodicalIF":1.0,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41559070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Vinegaroons are members of a guild of apex arthropod predators in the high desert grasslands of southeastern Arizona. Despite their importance as major predators in the ecosystem, almost nothing is known about their potential prey, predators, or competitors. We evaluated predator-prey relationships of vinegaroons and 30 species of potential prey, 27 species of potential predators, and the detailed interactions among three taxa of their apex predator guild. With few exceptions, vinegaroons overpowered and preyed on most potential prey within a suitable size range, were almost immune to predation, and appeared to be the dominant species in interactions with other predator guild members. Their most vulnerable life stages were the first two free-living instar stages, whereas adults and fourth instar individuals were not preyed on by any predators active in the same areas and times as vinegaroons. Third instar individuals were a crucial transition stage in which they had a few predators but also were large enough that they required capturing many prey items to grow sufficiently to molt to the fourth instar. In interactions among arthropod predators, the general observation was that when predation occurred, the larger individual usually prevailed irrespective of taxon. Cannibalism among adult and fourth instar vinegaroons does not occur under natural conditions in contrast to when they are placed together in artificial stressful situations. Cannibalism of the three smallest instars appears likely and might partially explain why they are solitary and spend minimal time foraging.
{"title":"Vinegaroons (Uropygi: Mastigoproctus tohono) in a multi-predator/multi-prey system: Prey, predators, and cannibalism","authors":"J. Schmidt, L. Schmidt","doi":"10.1636/JoA-S-21-005","DOIUrl":"https://doi.org/10.1636/JoA-S-21-005","url":null,"abstract":"Abstract. Vinegaroons are members of a guild of apex arthropod predators in the high desert grasslands of southeastern Arizona. Despite their importance as major predators in the ecosystem, almost nothing is known about their potential prey, predators, or competitors. We evaluated predator-prey relationships of vinegaroons and 30 species of potential prey, 27 species of potential predators, and the detailed interactions among three taxa of their apex predator guild. With few exceptions, vinegaroons overpowered and preyed on most potential prey within a suitable size range, were almost immune to predation, and appeared to be the dominant species in interactions with other predator guild members. Their most vulnerable life stages were the first two free-living instar stages, whereas adults and fourth instar individuals were not preyed on by any predators active in the same areas and times as vinegaroons. Third instar individuals were a crucial transition stage in which they had a few predators but also were large enough that they required capturing many prey items to grow sufficiently to molt to the fourth instar. In interactions among arthropod predators, the general observation was that when predation occurred, the larger individual usually prevailed irrespective of taxon. Cannibalism among adult and fourth instar vinegaroons does not occur under natural conditions in contrast to when they are placed together in artificial stressful situations. Cannibalism of the three smallest instars appears likely and might partially explain why they are solitary and spend minimal time foraging.","PeriodicalId":51076,"journal":{"name":"Journal of Arachnology","volume":"50 1","pages":"267 - 276"},"PeriodicalIF":1.0,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48859729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Grinsted, M. Schou, V. Settepani, Christina Holm, Lefang L. Chobolo, Galaletsang M. Dintwe, T. Bilde
Abstract. Sociality in spiders has evolved independently multiple times, resulting in convergently evolved cooperative breeding and prey capture. In all social spiders, prey is captured by only a subset of group members and then shared with other, non-attacking group members. However, spiders' propensity to attack prey may differ among species due to species-specific trade-offs between risks, costs and benefits of prey capture involvement. We explored whether engagement in prey attack differs among three social Stegodyphus species, using orthopteran prey, and found substantial differences. Stegodyphus mimosarum Pavesi, 1883 had a low prey acceptance rate, was slow to attack prey, and engaged very few spiders in prey attack. In S. sarasinorum Karsch, 1892, prey acceptance was high, independently of prey size, but more spiders attacked when prey was small. While medium-sized prey had higher acceptance rate in S. dumicola Pocock, 1898, indicating a preference, the number of attackers was not affected by prey size. Our results suggest that the three species may have different cooperative prey capture strategies. In S. mimosarum and S. dumicola, whose geographical ranges overlap, these strategies may represent niche specialization, depending on whether their respective cautious and choosy approaches extend to other prey types than orthopterans, while S. sarasinorum may have a more opportunistic approach. We discuss factors that can affect social spiders' foraging strategy, such as prey availability, predation pressure, and efficiency of the communal web to ensnare prey. Future studies are required to investigate to which extent species-specific cooperative foraging strategies are shaped by ontogeny, group size, and plastic responses to environmental factors.
{"title":"Diverging cooperative prey capture strategies in convergently evolved social spiders","authors":"L. Grinsted, M. Schou, V. Settepani, Christina Holm, Lefang L. Chobolo, Galaletsang M. Dintwe, T. Bilde","doi":"10.1636/JoA-S-20-097","DOIUrl":"https://doi.org/10.1636/JoA-S-20-097","url":null,"abstract":"Abstract. Sociality in spiders has evolved independently multiple times, resulting in convergently evolved cooperative breeding and prey capture. In all social spiders, prey is captured by only a subset of group members and then shared with other, non-attacking group members. However, spiders' propensity to attack prey may differ among species due to species-specific trade-offs between risks, costs and benefits of prey capture involvement. We explored whether engagement in prey attack differs among three social Stegodyphus species, using orthopteran prey, and found substantial differences. Stegodyphus mimosarum Pavesi, 1883 had a low prey acceptance rate, was slow to attack prey, and engaged very few spiders in prey attack. In S. sarasinorum Karsch, 1892, prey acceptance was high, independently of prey size, but more spiders attacked when prey was small. While medium-sized prey had higher acceptance rate in S. dumicola Pocock, 1898, indicating a preference, the number of attackers was not affected by prey size. Our results suggest that the three species may have different cooperative prey capture strategies. In S. mimosarum and S. dumicola, whose geographical ranges overlap, these strategies may represent niche specialization, depending on whether their respective cautious and choosy approaches extend to other prey types than orthopterans, while S. sarasinorum may have a more opportunistic approach. We discuss factors that can affect social spiders' foraging strategy, such as prey availability, predation pressure, and efficiency of the communal web to ensnare prey. Future studies are required to investigate to which extent species-specific cooperative foraging strategies are shaped by ontogeny, group size, and plastic responses to environmental factors.","PeriodicalId":51076,"journal":{"name":"Journal of Arachnology","volume":"50 1","pages":"256 - 264"},"PeriodicalIF":1.0,"publicationDate":"2022-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42205392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Paula E. Cushing, A. Brückner, Jesse W. Rogers, N. Horner
Abstract. The spider Myrmecicultor chihuahuensis Ramírez, Grismado & Ubick (Myrmecicultoridae) was described in 2019 and hypothesized to be a myrmecophile, living inside the nests of Novomessor (Myrmicinae) and perhaps also Pogonomyrmex (Myrmicinae) ants. To test the hypothesis that M. chihuahuensis are chemical mimics of their host ants, we carried out behavioral bioassays to observe interactions between the spiders and the host ants. We compared the cuticular hydrocarbon (CHC) profiles of the spiders and the ants. We discovered that this new species of spider is a myrmecophage, displaying hunting strategies similar to other myrmecophagous spiders, particularly those in the genus Zodarion Walckenaer, 1826 (Zodariidae). The CHC profile of M. chihuahuensis did not match the profile of the ants with which it associates, Novomessor albisetosus (Mayr), but ants and spider shared several compounds, potentially involved in species recognition.
{"title":"Trophic specialization of a newly described spider ant symbiont, Myrmecicultor chihuahuensis (Araneae: Myrmecicultoridae)","authors":"Paula E. Cushing, A. Brückner, Jesse W. Rogers, N. Horner","doi":"10.1636/JoA-S-21-072","DOIUrl":"https://doi.org/10.1636/JoA-S-21-072","url":null,"abstract":"Abstract. The spider Myrmecicultor chihuahuensis Ramírez, Grismado & Ubick (Myrmecicultoridae) was described in 2019 and hypothesized to be a myrmecophile, living inside the nests of Novomessor (Myrmicinae) and perhaps also Pogonomyrmex (Myrmicinae) ants. To test the hypothesis that M. chihuahuensis are chemical mimics of their host ants, we carried out behavioral bioassays to observe interactions between the spiders and the host ants. We compared the cuticular hydrocarbon (CHC) profiles of the spiders and the ants. We discovered that this new species of spider is a myrmecophage, displaying hunting strategies similar to other myrmecophagous spiders, particularly those in the genus Zodarion Walckenaer, 1826 (Zodariidae). The CHC profile of M. chihuahuensis did not match the profile of the ants with which it associates, Novomessor albisetosus (Mayr), but ants and spider shared several compounds, potentially involved in species recognition.","PeriodicalId":51076,"journal":{"name":"Journal of Arachnology","volume":"50 1","pages":"250 - 255"},"PeriodicalIF":1.0,"publicationDate":"2022-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43690428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. South Korea is a country with more than 1000 caves that support a high diversity of invertebrate species. Here we review the pseudoscorpion genus Spelaeochthonius Morikawa, 1954 (family Pseudotyrannochthoniidae) that is exclusive to caves in Japan and South Korea and reinstated here as a valid taxon. Based on recent field collections, three species in this genus are described from South Korea: S. dentifer (Morikawa, 1970), comb. nov., S. cheonsooi sp. nov., and S. seungsookae sp. nov. Based on present-day knowledge about range sizes and morphological variability in this fauna, three Japanese taxa currently classified as subspecies are elevated to species rank: Pseudotyrannochthonius kobayashii akiyoshiensis (Morikawa, 1956) = Spelaeochthonius akiyoshiensis Morikawa, 1956, stat. nov., Pseudotyrannochthonius kobayashii dorogawanesis (Morikawa, 1956) = Spelaeochthonius dorogawaensis Morikawa, 1956, stat. nov.; and Pseudotyrannochthonius undecimclavatus kishidai (Morikawa, 1960) = Spelaeochthonius kishidai (Morikawa, 1960), stat. nov. We emphasize that no epigean Spelaeochthonius have ever been found despite considerable search effort in the forests of Japan and Korea, and that past glacial cycling may have resulted in the total extirpation of surface species in this lineage. We also note that all species are narrow-range endemics that may require conservation management.
{"title":"Some cryptic Korean karst creatures: revalidation of the pseudoscorpion genus Spelaeochthonius (Pseudoscorpiones: Pseudotyrannochthoniidae) and description of two new species from Korea","authors":"JoonYong You, J. Yoo, M. Harvey, D. Harms","doi":"10.1636/JoA-S-21-025","DOIUrl":"https://doi.org/10.1636/JoA-S-21-025","url":null,"abstract":"Abstract. South Korea is a country with more than 1000 caves that support a high diversity of invertebrate species. Here we review the pseudoscorpion genus Spelaeochthonius Morikawa, 1954 (family Pseudotyrannochthoniidae) that is exclusive to caves in Japan and South Korea and reinstated here as a valid taxon. Based on recent field collections, three species in this genus are described from South Korea: S. dentifer (Morikawa, 1970), comb. nov., S. cheonsooi sp. nov., and S. seungsookae sp. nov. Based on present-day knowledge about range sizes and morphological variability in this fauna, three Japanese taxa currently classified as subspecies are elevated to species rank: Pseudotyrannochthonius kobayashii akiyoshiensis (Morikawa, 1956) = Spelaeochthonius akiyoshiensis Morikawa, 1956, stat. nov., Pseudotyrannochthonius kobayashii dorogawanesis (Morikawa, 1956) = Spelaeochthonius dorogawaensis Morikawa, 1956, stat. nov.; and Pseudotyrannochthonius undecimclavatus kishidai (Morikawa, 1960) = Spelaeochthonius kishidai (Morikawa, 1960), stat. nov. We emphasize that no epigean Spelaeochthonius have ever been found despite considerable search effort in the forests of Japan and Korea, and that past glacial cycling may have resulted in the total extirpation of surface species in this lineage. We also note that all species are narrow-range endemics that may require conservation management.","PeriodicalId":51076,"journal":{"name":"Journal of Arachnology","volume":"50 1","pages":"135 - 157"},"PeriodicalIF":1.0,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46823073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Spider webs in general and orb webs in particular are delicate, ephemeral structures that are frequently damaged in nature. Some orb weavers respond to damage by quickly “shoring up” their webs with non-sticky dragline silk. This study of how Micrathena duodecimspinosa (O. Pickard-Cambridge, 1890) shores up damaged frame lines shows that repairs were largely based on a single, repeated pattern of attachments. These movements are shared with the distantly related family Pholcidae, suggesting a possibly ancient origin. Spiders tended to initiate repairs at the lower edge of a damaged sector, probably to reduce the damage produced when the spider's own weight caused sticky lines in slack portions of the web to sag into and adhere to each other. Repairs of lateral frames recuperated capture area more successfully than did those of upper frames, probably because damage caused by the spider's own weight during repair was reduced.
{"title":"Frame line repair by the orb-weaver Micrathena duodecimspinosa (Araneae: Araneidae): possibly ancient behavior","authors":"W. Eberhard","doi":"10.1636/JoA-S-21-008","DOIUrl":"https://doi.org/10.1636/JoA-S-21-008","url":null,"abstract":"Abstract. Spider webs in general and orb webs in particular are delicate, ephemeral structures that are frequently damaged in nature. Some orb weavers respond to damage by quickly “shoring up” their webs with non-sticky dragline silk. This study of how Micrathena duodecimspinosa (O. Pickard-Cambridge, 1890) shores up damaged frame lines shows that repairs were largely based on a single, repeated pattern of attachments. These movements are shared with the distantly related family Pholcidae, suggesting a possibly ancient origin. Spiders tended to initiate repairs at the lower edge of a damaged sector, probably to reduce the damage produced when the spider's own weight caused sticky lines in slack portions of the web to sag into and adhere to each other. Repairs of lateral frames recuperated capture area more successfully than did those of upper frames, probably because damage caused by the spider's own weight during repair was reduced.","PeriodicalId":51076,"journal":{"name":"Journal of Arachnology","volume":"50 1","pages":"181 - 190"},"PeriodicalIF":1.0,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44608146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. According to a recent global literature survey, a total of 39 out of the 129 known spider families (∼30%) contain species capable of capturing vertebrate prey. The finding that the percentage of spider families engaged in vertebrate predation is so high is novel. Two groups of vertebrate-eating spiders are distinguished: “habitual vertebrate-eaters” vs. “occasional vertebrate-eaters”. The habitual vertebrate-eaters comprise ten spider families (Araneidae, Atracidae, Ctenidae, Lycosidae, Nephilidae, Pisauridae, Theraphosidae, Theridiidae, Trechaleidae, and Sparassidae) to which can be attributed 91% of all reported vertebrate predation incidents. The habitual vertebrate-eaters have evolved prey-capture adaptations such as (1) sufficient physical strength coupled with large body size, (2) the use of potent venoms, and (3) the use of highly efficient prey-catching webs. By contrast, unexpected feeding on vertebrates by the occasional vertebrate-eaters (i.e., Actinopodidae, Agelenidae, Amaurobiidae, Anyphaenidae, Barychelidae, Clubionidae, Corinnidae, Ctenizidae, Cyrtaucheniidae, Deinopidae, Desidae, Dipluridae, Eresidae, Filistatidae, Gnaphosidae, Haplonoproctidae, Linyphiidae, Liocranidae, Miturgidae, Oxyopidae, Pholcidae, Porrhothelidae, Salticidae, Selenopidae, Sicariidae, Sparassidae, Tetragnathidae, and Thomisidae) might be considered as chance events that took place when a tiny vertebrate crossed the path of an opportunistic spider. For a few families (e.g., Idiopidae) their status as habitual or occasional vertebrate predators is still unclear. In conclusion, our survey unveiled a large number of spider taxa previously not anticipated to feed on vertebrate prey. These findings improve our general understanding of spider feeding ecology and provide a first assessment of the significance of vertebrate prey as a food source for spiders.
{"title":"Spiders feeding on vertebrates is more common and widespread than previously thought, geographically and taxonomically","authors":"M. Nyffeler, J. Gibbons","doi":"10.1636/JoA-S-21-054","DOIUrl":"https://doi.org/10.1636/JoA-S-21-054","url":null,"abstract":"Abstract. According to a recent global literature survey, a total of 39 out of the 129 known spider families (∼30%) contain species capable of capturing vertebrate prey. The finding that the percentage of spider families engaged in vertebrate predation is so high is novel. Two groups of vertebrate-eating spiders are distinguished: “habitual vertebrate-eaters” vs. “occasional vertebrate-eaters”. The habitual vertebrate-eaters comprise ten spider families (Araneidae, Atracidae, Ctenidae, Lycosidae, Nephilidae, Pisauridae, Theraphosidae, Theridiidae, Trechaleidae, and Sparassidae) to which can be attributed 91% of all reported vertebrate predation incidents. The habitual vertebrate-eaters have evolved prey-capture adaptations such as (1) sufficient physical strength coupled with large body size, (2) the use of potent venoms, and (3) the use of highly efficient prey-catching webs. By contrast, unexpected feeding on vertebrates by the occasional vertebrate-eaters (i.e., Actinopodidae, Agelenidae, Amaurobiidae, Anyphaenidae, Barychelidae, Clubionidae, Corinnidae, Ctenizidae, Cyrtaucheniidae, Deinopidae, Desidae, Dipluridae, Eresidae, Filistatidae, Gnaphosidae, Haplonoproctidae, Linyphiidae, Liocranidae, Miturgidae, Oxyopidae, Pholcidae, Porrhothelidae, Salticidae, Selenopidae, Sicariidae, Sparassidae, Tetragnathidae, and Thomisidae) might be considered as chance events that took place when a tiny vertebrate crossed the path of an opportunistic spider. For a few families (e.g., Idiopidae) their status as habitual or occasional vertebrate predators is still unclear. In conclusion, our survey unveiled a large number of spider taxa previously not anticipated to feed on vertebrate prey. These findings improve our general understanding of spider feeding ecology and provide a first assessment of the significance of vertebrate prey as a food source for spiders.","PeriodicalId":51076,"journal":{"name":"Journal of Arachnology","volume":"50 1","pages":"121 - 134"},"PeriodicalIF":1.0,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47512031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Rhaucoides Roewer, 1912 is herein revisited and re-diagnosed based on somatic and genital morphology, including the differences of both expanded and unexpanded glans complex shown for the first time in Cosmetidae. The genus is characterized mainly by abdominal ornamentation, coloration and by having the two basalmost tarsomeres of leg I fused. The genus Cumbalia Roewer, 1963 is newly considered a junior synonym of Rhaucoides. The species Cumbalia octomaculata Roewer, 1963, Rhaucoides festae Roewer 1925 and Rhaucoides sulfureus Mello-Leitão 1939 are considered junior subjective synonyms of Rhaucoides riveti Roewer, 1919. Erginus devillei Simon 1879 (currently in Metarhaucus) is transferred to Rhaucoides, resulting in Rhaucoides devillei (Simon 1879), comb. nov. Rhaucoides atahualpa sp. nov. and Rhaucoides nasa sp. nov. are described from Ecuador and Colombia, respectively. Comments about the genital and tarsal morphology in Cosmetidae are provided. A map with the known distribution of the genus, in the Andes of southern Colombia and northern Ecuador, is given. Finally, emended diagnoses are provided for the genera Rhauculus Roewer, 1927 and Reimoserius Roewer 1947. After the type species of Metarhaucus Pickard-Cambridge, 1905 was transferred to Rhaucus Simon, 1879, a few species remained without formal generic allocation. All of those are herein combined either with Rhaucoides (1 species), Rhauculus (5 species) or Reimoserius (1 species).
{"title":"Rhaucoides Roewer, 1912, an Andean genus with fused tarsomeres: revision with a new generic synonymy and two new species (Opiliones: Cosmetidae: Metergininae)","authors":"M. Medrano, Andrés F. García, A. Kury","doi":"10.1636/JoA-S-21-028","DOIUrl":"https://doi.org/10.1636/JoA-S-21-028","url":null,"abstract":"Abstract. Rhaucoides Roewer, 1912 is herein revisited and re-diagnosed based on somatic and genital morphology, including the differences of both expanded and unexpanded glans complex shown for the first time in Cosmetidae. The genus is characterized mainly by abdominal ornamentation, coloration and by having the two basalmost tarsomeres of leg I fused. The genus Cumbalia Roewer, 1963 is newly considered a junior synonym of Rhaucoides. The species Cumbalia octomaculata Roewer, 1963, Rhaucoides festae Roewer 1925 and Rhaucoides sulfureus Mello-Leitão 1939 are considered junior subjective synonyms of Rhaucoides riveti Roewer, 1919. Erginus devillei Simon 1879 (currently in Metarhaucus) is transferred to Rhaucoides, resulting in Rhaucoides devillei (Simon 1879), comb. nov. Rhaucoides atahualpa sp. nov. and Rhaucoides nasa sp. nov. are described from Ecuador and Colombia, respectively. Comments about the genital and tarsal morphology in Cosmetidae are provided. A map with the known distribution of the genus, in the Andes of southern Colombia and northern Ecuador, is given. Finally, emended diagnoses are provided for the genera Rhauculus Roewer, 1927 and Reimoserius Roewer 1947. After the type species of Metarhaucus Pickard-Cambridge, 1905 was transferred to Rhaucus Simon, 1879, a few species remained without formal generic allocation. All of those are herein combined either with Rhaucoides (1 species), Rhauculus (5 species) or Reimoserius (1 species).","PeriodicalId":51076,"journal":{"name":"Journal of Arachnology","volume":"50 1","pages":"191 - 218"},"PeriodicalIF":1.0,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48836298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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