own here, from the rate of departure of spiders from web sites over several consecutive nights of observation. The major difference between the short-term results for Poltys and most of the other studies included here is the wide range of instars represented in the current studies and the inclusion of some spiders known to have experienced interactions with conspecifics. The overall figure from the long-term transects (all ages) is rather longer at 40.75 nights and is only second to the residence times of N. clavipes spiderlings among the silk recycling species in these examples. These Nephila were protected from predators in enclosures and provided with abundant prey, however, which is hardly a natural situation, and there are similar caveats for the long-term transect results for Poltys, discussed below. Nephila clavipes and P. noblei (Large spiders), have been shown to have an essentially random pattern of relocation from web sites (Vollrath & Houston 1986; Smith this paper); the pattern of relocation of the other orb web species at the bottom of the table has not been tested. These characteristics of long residence period and random relocation pattern suggest some hidden high cost of moving may be present for each species in comparison to the presumed freely moving spiders at the top of Table 1.
[FIGURE 2 OMITTED]
The risk of predation, or expenditure of energy associated with avoiding such a fate, has previously been suggested to be this hidden cost for the diurnal species with long residence periods. For Nephila there is a direct risk after relocating due to the lack of protection usually afforded by an extensive barrier web (labyrinth) at an established site (Vollrath 1985). In the case of C. octotuberculata, the spider hides among debris and egg sacs that are incorporated in a line across its web. The line of debris is taken by the spider when it relocates and although this protects the spider after arrival at a new site, carrying such a burden takes more energy and time (Nakata & Ushimaru 2004). In the same study Cyclosa argenteoalba Bosenberg & Strand 1906 was compared with C. octotuberculata. This species does not use debris for camouflage in the web and correspondingly was found to have a much shorter average residence time (Table 1). Even in certain spiders that do not recycle web proteins, predation during relocation has been found to be a major cost that favors long residence periods. Only 60% of desert widow spiders, Latrodectus revivensis Shulov 1948, survived relocation, far outweighing the material cost due to loss of silk (Lubin et al. 1993).
Like the desert widow spider mentioned above, the remaining orb web species with long residence times, P. noblei and Tetragnatha elongata Walckenaer 1842, are primarily nocturnal. Nocturnally active spiders largely avoid the dangers of being exposed in a web by day, but still require a strategy to avoid predation during this time while the majority of predators are active. Some, like L. revivensis, hide in a retreat that may offer a physical barrier against some predators as well as concealing the spider; other taxa, such as these Poltys and Tetragnatha Latreille 1804 species, rely on camouflage. This camouflage is manifested both in coloration and shape. Tetragnatha are elongate and usually lie on vegetation with legs extended linearly, blending in with the twig or leaf, while Poltys sit on the side or end of a twig with legs tucked in, appearing like a broken twig end or a dead leaf bud. Voluntary relocation would take place during the night, so one cost is loss of foraging time. But for these spiders the main danger in moving from a known "safe" web site may be the risk of not matching the substrate at a new, unknown, site and thereby becoming easily visible to a predator.
[FIGURE 3 OMITTED]
Movement strategies of spiders in different age classes are provided by the long-term results of the present study (Figs. 3a-c) and the seasonal analysis (Tables 2a, b). For P. noblei, the non-random pattern of residence of Small spiders compared to the apparently random p