Paula E. Cushing

Distribution of the Medically-implicated Hobo Spider (Araneae: Agelenidae) and a Benign Congener, Tegenaria duellica, in the United States and Canada

Abstract The hobo spider, Tegenaria agrestis (Walckenaer), and the related Tegenaria duellica Simon are very similar European spiders that have become well established in the northwestern United States and British Columbia. The hobo spider is considered to be medically important; T. duellica is considered harmless but is often misidentified as the hobo spider. The current distribution of the hobo spider includes southern British Columbia, Washington, Oregon, Idaho, northern Utah, the western half of Montana, western Wyoming, and two small, isolated populations in Colorado. T. duellica is found mostly west of the Cascade and Coastal mountain ranges from southern British Columbia to central Oregon. In large human population centers where both species are sympatric, T. duellica is usually more common than the hobo spider. Data from a total of 1,232 hobo spiders and 395 T. duellica are included in this study.

NOTES ON THE NATURAL HISTORY AND HUNTING BEHAVIOR OF AN ANT EATING ZODARIID SPIDER (ARACHNIDA, ARANEAE) IN COLORADO

Abstract The ant hunting behavior of Zodarion rubidum (Araneae, Zodariidae) is described from specimens collected in Colorado, USA. Like other members of this genus, Z. rubidum constructs igloo-shaped stone retreats under rocks and feeds on ants. Details of the prey capture behavior are provided including initial and subsequent reactions of ants to the bites of Z. rubidum and data on the time it takes for ants to become completely paralyzed as a result of the bites.

Molecular characterization of Russian wheat aphid consumption by spiders in winter wheat

Abstract Accurate characterization of predator-prey linkages in agroecosystems is important prior to the implementation of conservation biological programs. The Russian wheat aphid, Diuraphis noxia (Hemiptera: Aphididae), is a significant pest of wheat and barley in the United States. This research utilized molecular gut-content analysis as a minimally disruptive technique to characterize the trophic connectivity between two spider species, Tetragnatha laboriosa Hentz 1850 and Pardosa sternalis (Thorell 1877), and D. noxia. We describe the development of species-specific primers that amplify a 227 bp fragment of D. noxia COI mtDNA to identify the frequency of predation under varying aphid densities and developmental stages of winter wheat. We tested the hypotheses that predation rates on D. noxia would be highest for both spider species at the greatest aphid infestation level in the aphid-resistant wheat cultivar plots and that densities of T. laboriosa would be highest at the highest aphid infestation level in the aphid-resistant cultivars. Despite short detection periods of prey DNA in the laboratory, 32% and 48% of field-collected T. laboriosa and P. sternalis spiders screened positive for D. noxia DNA, respectively. T. laboriosa densities were highest at the highest aphid infestation level. Aphid-resistant wheat cultivars did not impact predation rates or densities. Additionally, P. sternalis predation on D. noxia increased with increasing aphid infestation levels. Given the high predation rates on D. noxia and their association with increased aphid densities, both spider species represent important natural enemies within wheat agroecosystems, and further research is required to quantify their impact on aphid populations.

THE SYSTEMATICS OF THE EREMOBATES SCABER SPECIES-GROUP (SOLIFUGAE, EREMOBATIDAE)

Abstract The scaber group of the genus Eremobates is reviewed in terms of new characters and a more restricted biogeographic area. Three new species are described from the U.S.A.: Eremobates socal (California), E. icenoglei (California), E. corpink (Utah). We synonymize E. gladiolus Muma with E. scaber (Kraepelin); E. consors Muma, E. ascopulatus Muma and E. flavus with E. ascopulatus Muma; and E. mimbrenus Muma with E. mormonus (Roewer). Eremobates scaber, E. hodai Muma, E. clarus Muma, E. similis Muma are now described from both sexes. All scaber species except the Mexican species, E. legalis Harvey, are now known from both sexes. We also present the first phylogeny of the species group based on morphological characters. This phylogeny demonstrates a geographic grouping into northern and southern clades.

NEW SPECIES OF EREMOBATIDAE (ARACHNIDA, SOLIFUGAE) FROM NORTH AMERICA

Abstract Five new species of Solifugae are described from North America: Eremobates chihuaensis, Eremobates gerbae, Hemerotrecha sevilleta, Hemerotrecha cornuta, Eremochelis oregonensis as well as the females of Eremocosta gigasella (Muma, 1970), and Eremobates polhemusi Muma & Brookhart, 1988.

Preliminary survey of the setal and sensory structures on the pedipalps of camel spiders (Arachnida: Solifugae)

Abstract Solifuges, or camel spiders (order Solifugae), keep their pedipalps extended when moving through the environment, utilizing them much the way insects use their antennae. The male also uses his pedipalps during copulation, staying in contact with the female throughout the process. The pedipalps are covered with setae that are assumed to function as chemo-, mechano-, thermo-, hygro-, and olfactory receptors. We surveyed setal forms and other possible sensory structures on the pedipalps of solifuges to determine 1) if certain setae and structures are common to all families, 2) if some may be unique to certain families, and 3) the possible function of the various setae and other structures. We found that all families had bifurcated and tapered setae, and that all families had dorsal tarsal pores. Other setal forms were evident only in one or a few families. Three of the setal types had distal pores suggesting that they function as chemoreceptors. These data suggest that the pattern and types of setae on the pedipalps of solifuges may be phylogenetically informative and confirm that the pedipalps do function as sensory appendages.

Natural history of coastal Peruvian solifuges with a redescription of Chinchippus peruvianus and an additional new species (Arachnida, Solifugae, Ammotrechidae)

Abstract Two species of Chinchippus (Ammotrechidae) were studied in central Peru. Both species are endemic to the hyper-arid coastal desert and appear to derive most of their energy and nutrients from maritime prey, such as intertidal amphipods feeding on beach-cast algae or as arthropod scavengers feeding upon seabird and pinniped carcasses. Data on the spatial distribution of the two species were obtained from analyzing stomach contents of one common predator, the gecko Phyllodactylus angustidigitus, and suggest that both species are more abundant in insular than in mainland habitats. We redescribe Chinchippus peruvianus Chamberlin 1920, known only from a female specimen and describe the male for the first time while C. viejaensis is recognized as new. The new species is distinguished from C. peruvianus by its darker coloration, smaller size, and differences in cheliceral dentition.

Revision and morphological phylogenetic analysis of the funnel web spider genus Agelenopsis (Araneae: Agelenidae)

Abstract The Nearctic agelenid spider genus Agelenopsis Giebel 1896 is revised, with redescriptions of the 13 known species including: A. actuosa (Gertsch & Ivie 1936), A. aleenae Chamberlin & Ivie 1935, A. aperta (Gertsch 1934), A. emertoni Chamberlin & Ivie 1935, A. kastoni Chamberlin & Ivie 1941, A. longistyla (Banks 1901), A. naevia (Walckenaer 1841), A. oklahoma (Gertsch 1936), A. oregonensis Chamberlin & Ivie 1935, A. pennsylvanica (C.L. Koch 1843), A. potteri (Blackwall 1846), A. spatula Chamberlin & Ivie 1935, and A. utahana (Chamberlin & Ivie 1933). We also include an identification key to the species and a species distribution map. Our cladistic analysis of Agelenopsis is based upon 31 genitalic and somatic characters using Hololena hola (Chamberlin 1928) as the outgroup taxon and including three species of Barronopsis Chamberlin & Ivie 1941 in the analysis since Barronopsis has been considered a sister taxon to Agelenopsis in previous work. The cladistic analysis found 22 most parsimonious trees unambiguously supporting Agelenopsis monophyly. The majority rule consensus provides support for a clade including (((A. pennsylvanica + A. potteri) + A. actuosa) + A. emertoni); another clade including ((((A. aleenae + A. spatula) + A. aperta) + A. kastoni) + A. naevia); and a third clade including ((A. oregonensis + A. utahana) + A. longystyla). Our analysis supports species groups proposed by researchers using molecular characters.

Ant mimicry in the spider Myrmecotypus iguazu (Araneae: Corinnidae), with notes about myrmecomorphy in spiders

Abstract We describe the mimetic relationship between the ant-like spider Myrmecotypus iguazu Rubio & Arbino 2009 (Araneae: Corinnidae) and the carpenter ant Camponotus sericeiventris Guérin (Hymenoptera: Formicidae), studied in a subtropical rainforest in Iguazú National Park, Argentina. The morphological adaptations, aspects of coloration, and behavior responsible for the ant-like appearance in M. iguazu (the mimic) provide strong evidence that its model is C. sericeiventris. Both field observations and field and laboratory experiments suggest that this spider is a Batesian mimic.

THREE NEW SPECIES OF SOLIFUGAE FROM NORTH AMERICA AND A DESCRIPTION OF THE FEMALE OF BRANCHIA BREVIS (ARACHNIDA, SOLIFUGAE)

Abstract Three new species of Solifugae are described: Eremobates paleta from Mexico, is a member of the Eremobates scaber species group; Eremobates inkopaensis from California, U.S.A., is a member of the Eremobates palpisetulosus group; and Eremochelis albaventralis from Mexico is tentatively placed in the Eremochelis bilobatus group. The female of Branchia brevis Muma from Texas, U.S.A. is described for the first time.