Life-history data for the funnel weavers Eratigena agrestis and Eratigena atrica (Araneae: Agelenidae) in the Pacific Northwest of North America

2017 ◽  
Vol 149 (3) ◽  
pp. 345-356
Author(s):  
Samantha Vibert ◽  
Maxence Salomon ◽  
Catherine Scott ◽  
Gwylim S. Blackburn ◽  
Gerhard Gries

AbstractThe life history of the funnel weaver Eratigena agrestis (Walckenaer) (Araneae: Agelenidae) is not well studied despite its widespread occurrence in Europe and its establishment and spread in the Pacific Northwest of North America since its introduction in the early 20th century. We report phenology and life-history data for E. agrestis and another co-occurring funnel weaver, Eratigena atrica (Koch), in two study sites in British Columbia, Canada. The most notable difference in phenology between the two Eratigena species was the timing of emergence: E. atrica spiderlings emerge in the fall whereas E. agrestis spiderlings emerge in the spring. Surprisingly, the contrasting densities of E. atrica in the two study sites and the presence of the western black widow spider, Latrodectus hesperus Chamberlin and Ivie (Araneae: Theridiidae), in one study site had little effect on the life history of E. agrestis. This unexpected finding may be explained by (i) low overall competition pressure in the study habitats, (ii) conspecifics and heterospecifics exerting equivalent competition or predation pressures; and/or (iii) aggregations of heterospecifics providing benefits that offset costs associated with any competition.

Zootaxa ◽  
2010 ◽  
Vol 2413 (1) ◽  
pp. 61 ◽  
Author(s):  
D. CHRISTOPHER ROGERS ◽  
STEPHEN C. WEEKS ◽  
WALTER R. HOE

Eulimnadia graniticola n. sp. from Stone Mountain, Georgia, and the Florida Keys, USA, is defined primarily on molecular characters and egg morphology. Ecological, reproductive and life history data are provided. This species is the second species of branchiopod crustacean reported from Stone Mountain more closely related to the South American fauna than to its North American congeners.


2004 ◽  
Vol 5 (1) ◽  
pp. 16
Author(s):  
Dean A. Glawe

Chinese matrimony-vine (Lycium chinense Mill.) is a traditional medicinal plant grown in China and used as a perennial landscape plant in North America. This report documents the presence of powdery mildew on L. chinense in the Pacific Northwest and describes and illustrates morphological features of the causal agent. It appears to be the first report of a powdery mildew caused by Arthrocladiella in the Pacific Northwest. Accepted for publication 10 November 2004. Published 8 December 2004.


Parasitology ◽  
1964 ◽  
Vol 54 (4) ◽  
pp. 601-676 ◽  
Author(s):  
J. C. Pearson

Earlier schemes of classification of the family Heterophyidae have been based in large part on such features as shape of body, presence of oral spines, number and position of testes, and distribution of vitellaria (Witenberg, 1929; Ciurea, 1933; Mueller & Van Cleave, 1932). Price (1940a) was the first to make extensive use of features of the ventrogenital complex (ventral sucker, gonotyl, genital pore, terminal male duct) and excretory bladder, and produced the first reasonable classification of both the family Heterophyidae and the superfamily Opisthorchioidea. In despite of the obvious significance of the rationale of Price's approach, later authors (Morozov, 1952, 1955; Yamaguti, 1958) have largely ignored the ventrogenital complex and recently discovered life-history data, and have used much the same sorts of features as earlier authors.


2014 ◽  
Vol 51 (11) ◽  
pp. 1023-1033 ◽  
Author(s):  
Evan Vanderven ◽  
Michael E. Burns ◽  
Philip J. Currie

The Danek Bonebed (Edmonton, Alberta, Canada) is a monodominant Edmontosaurus regalis assemblage of the upper Campanian (Upper Cretaceous) Horseshoe Canyon Formation. Bone histology of humeri and femora are used in this paper to test hypotheses about the growth dynamics and palaeobiology of Edmontosaurus. The high number of elements collected from the Danek Bonebed allow for an expansion of the multi-element histological record for hadrosaurs. Results indicate that Edmontosaurus had a growth trajectory similar to other large-bodied dinosaurs and reached the onset of somatic maturity at about 10–15 years of age; however, even the largest elements to preserve lines of arrested growth do not have external fundamental systems. This timing of the onset of somatic maturity agrees with the estimated body size of Edmontosaurus relative to other dinosaurs for which life-history data are available. Vascularity patterns support the hypothesis that edmontosaurs preserved at the Danek Bonebed were not subject to the same extreme seasonal environmental shifts as congenerics preserved at higher latitudes, further supporting overwintering behaviour in the latter.


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