Energetic cost of web construction and its effect on web relocation in the web-building spider Agelena limbata

Abstract

Although spider webs may be effective in trapping prey, they require energy for construction. The design of webs varies in complexity from species to species. I assume that the energetic cost of web construction is significantly different among web types or species. This cost may constrain foraging tactics, particularly web relocation, because web relocation also requires energy to make a new web. To clarify the effect of the cost of web construction on web relocation, the energy cost of web construction and the rate of web relocation were estimated for the spider Agelena limbata. This spider constructs a sheet-funnel web consisting of a tight mesh of silk threads. This web was costly in terms of the energy needed for construction, which ranged from 9 to 19 times the daily maintenance energy. The daily rate of web relocation was below 1%, indicating high web-site tenacity. Relocation rates of species which built different types of web were compared in relation to cost of web construction. Orbweavers, which produce less costly webs than sheet-funnel weavers, relocate webs more frequently. Sheetweavers, which make webs of intermediate cost, appear to relocate webs more frequently than sheetfunnel weavers but less frequently than orbweavers. These results suggest that the energy cost of web construction is important in determining the frequency of web relocation.

The complete mitochondrial genome of Agelena silvatica (Araneae: Agelenidae)

“…The species, Agelena silvatica Oliger, 1983 (Araneae: Agelenidae), previously known as A. limbata Thorell, 1897 since B€ osenberg andStrand (1906), is a common species in East Asia (found in South China, Korea, Japan) and Far East of Russia (Zhang et al 2005). Generally, this species has large body size (10-20 mm), constructs a typical funnel web on shrubs or trees to trap insect or other animals (Tanaka 1989). Studies on ecology, physiology, and behaviour of this species have been carried out well (Tanaka 1984(Tanaka , 1991(Tanaka , 1995Masumoto 1994;Park & Moon 2002).…”

Life History of the Funnel-web Spider Agelena limbata: Web Site, Growth, and Reproduction.

“…The open habitat affords poorer prey availability (TANAKA, 1991), which may cause longer time for maturation of an ovary and, therefore, preovipositional period may be prolonged. Females guarded the egg sacs for more than a month.…”

“…In the open habitat, heat stress suppressed foraging activities of spiders in summer, which resulted in less food consumption, about a half of that in the woody habitat (TANAKA, 1991). The limited prey availability certainly caused smaller body size and fertility in the open habitat population.…”

“…Spiders are a large group of predators and often abundant in various environments (TURNBULL, 1973), and play an important role as predators in natural and agricultural ecosystems (for review, see RIECHERT and ROCKLEY, 1984;NYFFELER and BENTZ, 1987;TANAKA, 1989 a). Nevertheless there are only a few works that show life history parameters including a survivorship curve or a mortality pattern covering an entire life cycle of a spider species in the field (e.g.…”

“…I have so far reported a survivorship curve and mortality factors of A. limbata together with some aspects of foraging ecology, i.e. energetic cost of web construction, web relocation rate, and prey capture rate (TANAKA, 1984(TANAKA, , 1989b(TANAKA, , 1991). This paper describes several aspects of life history of A. limbata, i.e.…”