Energy costs of the predation strategy of the web-spinning spider Lepthyphantes zimmermanni bertkau (Linyphiidae)
The energy costs of the predation strategy of the web-spinning spider Lypthyphantes zimmermanni were investigated in the laboratory. The standard respiratory costs associated with the stationary aspect of the strategy were estimated by means of a Gilson respirometer run at the different temperatures prevailing month by month in the beech woodland litter layer which comprises the spider's natural habitat. Respiration rate is related to weight by an exponent with a mean value of 0.7398. The Q10 of respiration rate is 2.41 between 5°C and 10°C and 1.97 between 10°C and 15°C. The energy costs of producing a web comprise the active respiratory costs associated with the locomotory activity involved in spinning a web together with the energy value of the silk used in the web manufacture. The former were evaluated by allowing a spider to spin a web in a respirometer, subtracting the calculated standard respiratory energy costs for a spider of equivalent weight and multiplying by a correction factor for web size. The relationship between spider weight and area of web produced was established in the laboratory. The respiratory cost of spinning a web is effectively constant with temperature at 724.46·10-3 J for an adult (4 mg) spider. The energy value of spider silk was estimated by means of a bomb calorimeter and found to be 17,435 J g-1. The energy content of the silk of a single adult's web is 1.16 J, giving energy cost of web production of 1.88 J at all temperatures.
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- Duffey, E.: Changes in the British spider fauna. In: The changing flora and fauna of Britain (D.L. Hawksworth, ed.), pp. 293–305, Syst. Assoc. Spec Vol. 6. London-New York: Academic Press 1974Google Scholar
- Ford, M.J.: Comparative metabolic studies on woodland spiders. D. Phil. thesis, University of Oxford (1975)Google Scholar
- Ford, M.J.: Metabolic costs of the predation strategy of the spider Pardosa amentata (Clerck) (Lycosidae). Oecologia (Berl.) 28, 333–340 (1977)Google Scholar
- Gilson, W.E.: Differential respirometer of simplified and improved design. Science 141 531–532 (1964)Google Scholar
- Lucas, F.: Spiders and their silks. Discovery 25, 20–26 (1964)Google Scholar
- Lucas, F., Rudall, K.M.: Extracellular fibrous proteins: the silks. In: Comprehensive biochemistry (M. Florkin, E.H. Stotz, eds.), Vol. 26, Part B, pp. 475–558. Amsterdam-London-New York: Elsevier 1968Google Scholar
- Macfadyen, A.: Animal ecology: aims and methods, 2nd ed. London: Pitman 1963Google Scholar
- Peakall, D.B.: Composition, function and glandular origin of the silk fibroins of the spider Araneus diadematus Cl. J. exp. Zool. 156, 345–352 (1964)Google Scholar
- Petrusewicz, K., Macfadyen, A.: Productivity of terrestrial animals, I.B.P. Handbook No. 13. Oxford-Edinburgh: Blackwells 1970Google Scholar
- Phillipson, J.: A miniature bomb calorimeter for small biological samples. Oikos 15, 130–139 (1964)Google Scholar
- Schoener, T.W.: Models of optimal size for solitary predators. Amer. Naturalist 103 277–313 (1969)Google Scholar
- Schoener, T.W.: Theory of feeding strategies. Ann. Rev. Ecol. Syst. 2, 369–404 (1971)Google Scholar