non-random patterns of residence times at web sites, either tending to move on more quickly than expected, or staying much longer than expected. The implication of this finding is that these species are not constrained by costs and can move whenever it is most appropriate in terms of prey abundance or other factors. In contrast, some sheet-weaving spiders (Linyphiidae), which do not recycle their silk proteins, have a much greater energy cost when moving to a new site (Janetos 1982a). Accordingly, the relocation patterns of these sheet-weavers did not differ significantly from that expected due to random events (i.e., the cost of abandoned silk and energy is a strong deterrent to relocation unless necessitated by other factors). Based on this premise, a spider that recycles silk but has a random pattern of movement nonetheless may have a high cost of moving due to some other factor. An increased risk of predation during and after relocation was identified as this factor in the case of the orb web spider Nephila clavipes (Linnaeus 1767) (Vollrath & Houston 1986).
Frequency of relocation.--In work on orb web spiders, the frequency of relocation, or its inverse, the average length of residence at a site, has been used to demonstrate a response to factors such as changes in prey levels (Olive 1982; Vollrath 1985) , web damage (Enders 1976), and intraspecific interactions (Smallwood 1993). These are among the many factors that together influence the suitability of a site for any particular spider at any given time (Riechert & Gillespie 1986) . What may be most difficult to quantify are the negative influences, (i.e., those such as an increased risk of predation that could cause a spider to move less frequently than might otherwise be expected). These factors may be easiest to examine indirectly by comparing the habits of different species and their respective life histories, and considering the differences among them. As an example, Miyashita (2005) found that the likelihood of risk-taking in two Nephila Leach 1815 species appeared to correlate to their life histories--females of N. pilipes (Fabricius 1797) need to grow fast to reach the normally large adult body size, and this species is more likely to risk moving than the sympatric species N. clavata L. Koch 1878, which is smaller and may be able to afford periods of suboptimal growth.
Web site residency times are given as examples in Table 1. Most are for orb web spiders that recycle their silk; other web builders are included for comparison. Even among the orb web builders a wide range of variation can be seen between those at the top of the table, which move most frequently, and those at the bottom with the longest residency times. In this paper, I examine the frequency and pattern of the web site movements of the araneid spider Poltys noblei Smith 2006 in bushland near Sydney, Australia. I compare the results with those of other species in Table 1 and discuss the risks of predation and the role of camouflage in prolonging web site residence times. Unlike many other spiders, P. noblei may over-winter at almost any size (Smith 2006b). The data gathered for the web site tenacity study is useful for examining the seasonality of movements of these spiders through the year.
Spiders of the genus Poltys C.L. Koch 1842 are nocturnal orb web builders that remove their web around dawn and rebuild it each evening. Poltys noblei and other southern species inhabit bushland areas where trees and bushes commonly have patches of dead twigs. During the hours of daylight, when not in a web, the spiders rest camouflaged by shape and color on a bare, dead twig, often in an exposed position (Fig. 1a). Poltys males are small and can mature in just a few weeks if emerging during the summer months, but females have a longer lifespan, which in P. noblei probably lasts from one to two, or even more, years. Spiderlings are similar in abdominal morphology but a wide range of abdominal shapes and coloration develops as individuals grow towards maturity (Fig. 1 a-d; Smith 2006a, b). This intraspecifi