Calculation of Capture Thread Length in Orb Webs: Evaluation of New Formulae

Heiling, Astrid M.; Herberstein, Marie E.; Spitzer, G

doi:10.1093/aesa/91.1.135

Cited by 18 publications

(7 citation statements)

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“…The general web architecture is thought to be genetically determined (Foelix 1992). Capture area and capture thread length increased significantly with carapace width in this study, a result also reported by Heiling et al (1998). A large capture area results in high prey interception (Chacon & Eberhard 1980), and by increasing the distance between sticky spirals, spiders may enlarge the overall capture area without increasing their energy expenditure (Herberstein et al 2000).…”

Section: Prey Typesupporting

confidence: 85%

Foraging strategies and diet composition of two orb web spiders in rice ecosystems

Tahir¹,

Butt

Sherawat³

2009

Journal of Arachnology

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We conducted a field study in September 2007 and2008 to analyze the foraging activity, natural diets, and predatory efficacy of Tetragnatha javana (Thorell 1890) (Araneae: Tetragnathidae) and Neoscona theis (Walckenaer 1842) (Araneae: Araneidae) on selected prey. The relationship between body measurements (carapace width, leg length, total body length, and body weight) and web dimensions (capture area, capture thread length, number of radii, number of spirals, and mesh height) of both species was also investigated. Most of the observed T. javana constructed their webs between two adjacent rice plants, while N. theis placed theirs at the top of rice plants. Both species required approximately an hour to complete a web, which differed significantly from each other in height, diameter, and capture area. Both species constructed only a single web per day. Web building activity of both species was intense from 17:00 to 18:00, while preyhandling activity was high from 19:00 to 20:00. In both species, peaks of feeding were recorded just after the peaks of prey handling (21:00). The main prey orders caught in the webs of both species were Lepidoptera, Diptera, Homoptera, Coleoptera, Hymenoptera, and Orthoptera. The time required to reach and capture lepidopteran (adults of stem borer and leaf folder) and homopteran prey was similar for both species. However, the time required to reach and capture orthopteran (grasshopper nymphs) prey was significantly longer for T. javana than for N. theis. Capture area increased with carapace width, and capture thread length increased with carapace width and body weight, while leg length and body length did not relate to either of these web variables. The number of radii, number of spirals, and mesh height did not correlate with any of the body size measurements. We concluded that both species can be used effectively to reduce insect pests of rice fields.

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Section: Prey Typesupporting

confidence: 85%

Foraging strategies and diet composition of two orb web spiders in rice ecosystems

Tahir¹,

Butt

Sherawat³

2009

Journal of Arachnology

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“…Hence, web-building effort used to be directly estimated by means of web size and/or thread length of webs (Witt et al 1968;Sherman 1994;Heiling et al 1998;Nakata and Ushimaru 1999;Venner et al 2001). However, here we have demonstrated that neither web size nor amount of silk used per web could be considered direct indicators of a spider's energetic investment devoted to foraging: despite using less silk to build their webs and building smaller webs, heavier spiders still spent more energy in web building.…”

Section: Discussionmentioning

confidence: 58%

Body-mass-dependent cost of web-building behavior in an orb weaving spider, Zygiella x-notata

Venner¹,

Bel‐Venner²,

Pasquet³

et al. 2003

Naturwissenschaften

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In numerous spider species, reproductive success of adult females has been shown to be positively correlated with their body mass. We suggest, however, that spiders may incur greater foraging costs as their body mass increases due to the numerous and complex locomotor bouts needed to build an orb-web. Such a body-mass-dependent cost should, in turn, affect the web-building decisions of spiders. In the laboratory, we tested the influence of body mass on energetic expenditure (measured as mass loss) during web-building behavior in Zygiella x-notata. Our results showed (1) that energetic costs associated with web-building were closely related to body mass and to web-building activity, and (2) that as their body mass increased, spiders reduced the amount of silk used per web, while their foraging effort simultaneously increased. This work gives new insights into web-building behavior and energy allocation strategies of weaving spiders.

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“…We measured webs from digital photos using imagej (National Institutes of Health, USA) and took the measurements summarized in Table (see also Figure ). Capture thread length (CTL), the total length of sticky capture spiral, was estimated using the large‐scale formula of Heiling, Herberstein, and Spitzer ():

CTL = \sum ((T_{l} + T_{s}) / 2) \times x_{i},

where for a given sector i of the web, x i is the number of rows of capture thread, T l is the length of the outermost (longest) row of capture thread, and T s is the length of the innermost (shortest) row of capture thread.…”

Section: Methodsmentioning

confidence: 99%

Spider webs, stable isotopes and molecular gut content analysis: Multiple lines of evidence support trophic niche differentiation in a community of Hawaiian spiders

et al. 2019

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Adaptive radiations are typically characterized by niche partitioning among their constituent species. Trophic niche partitioning is particularly important in predatory animals, which rely on limited food resources for survival. We test for trophic niche partitioning in an adaptive radiation of Hawaiian Tetragnatha spiders, which have diversified in situ on the Hawaiian Islands. We focus on a community of nine species belonging to two different clades, one web‐building and the other actively hunting, which co‐occur in wet forest on East Maui. We hypothesize that trophic niches differ significantly both: (a) among species within a clade, indicating food resource partitioning, and (b) between the two clades, corresponding to their differences in foraging strategy. To assess niches of the spider species, we measure: (a) web architecture, the structure of the hunting tool, and (b) site choice, the physical placement of the web in the habitat. We then test whether differences in these parameters translate into meaningful differences in trophic niche by measuring (c) stable isotope signatures of carbon and nitrogen in the spiders’ tissues, and (d) gut content of spiders based on metabarcoding data. We find significant interspecific differences in web architecture and site choice. Importantly, these differences are reflected in stable isotope signatures among the five web‐building species, as well as significant isotopic differences between web‐builders and active hunters. Gut content data also show interspecific and inter‐clade differences. Pairwise overlaps of web architecture between species are positively correlated with overlaps of isotopic signature. Our results reveal trophic niche partitioning among species within each clade, as well as between the web‐building and actively hunting clades. Based on the correlation between web architecture and stable isotopes, it appears that the isotopic signatures of spiders’ tissues are influenced by architectural differences among their webs. Our findings indicate an important link between web structure, microhabitat preference and diet in the Hawaiian Tetragnatha. A free Plain Language Summary can be found within the Supporting Information of this article.

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Calculation of Capture Thread Length in Orb Webs: Evaluation of New Formulae

Cited by 18 publications

References 0 publications

Foraging strategies and diet composition of two orb web spiders in rice ecosystems

Foraging strategies and diet composition of two orb web spiders in rice ecosystems

Body-mass-dependent cost of web-building behavior in an orb weaving spider, Zygiella x-notata

Spider webs, stable isotopes and molecular gut content analysis: Multiple lines of evidence support trophic niche differentiation in a community of Hawaiian spiders

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