ed pattern of residence times was compared with a random hypothesis, following the methods of Janetos (1982a) and Hodge (1987a, b). This method is based on the expectation that compounded random events such as web damage or disturbance by a predator should result in spider movement events that can be explained by a Poisson process (Janetos 1982a). A negative exponential series was generated (using the "expondist" function in Microsoft Excel), which models the expected distribution of spider movement events over time according to this random hypothesis. This distribution of class frequencies was then compared with that collated from the recorded data.
Seasonality of spider relocations.--In order to compare differences in spider relocation as a function of season, the same size classes were used as for the calculation of residence periods except that the Large spider size class was split into Medium and Large. Thus, Large in this context only contains adult and subadult females; these were split off because all adults die by winter and will therefore leave a web site. Data were extracted for each residency from the long-term observations at Waitara Creek--the season a spider moved into a position and its size, the seasons during which it was resident at a position, and the season and size at which it moved on (Smith 2006b). If a spider had grown between size-classes during its period of residence, the original data were examined to separate the seasons in which the two different size classes were present. For each kind of move, in or out, and for each size class of spider, the total number of moves per season was calculated as a proportion of the numbers of spiders in that class recorded during the season.
Short-term observations of residence time.--The residence period through each short-term transect period is 24.9 nights, averaged over all three sites. Per site the averages are: Myall, 26.3 nights; Waitara Creek, 23.5 nights; West Head, 23.9 nights. The presence of individual spiders through the recording period at each site is depicted in Fig. 2. All spiders were used for the calculations, which therefore include movements due to conspecific interference.
Long-term observations of residence time.--The mean residence time for all spiders is 4.80 recording periods (40.75 days), SD = 5.57, n = 218. The longest recorded residence is 31 recording periods (approximately 263 days) (Fig. 3a). When Small and Large residence times are compared, the distribution of residence times is found to be significantly different between the two size classes (P = 0.012). The mean residence times are 3.77 sampling periods, (32 days), for Small spiders (SD = 4.51, n = 138), and 6.59 sampling periods (56 days), for Large spiders (SD = 6.69, n = 80). Most aggregated spiders were omitted in calculating these figures; hence movements due to conspecific interference are minimal.
The distribution of residence times of Small spiders is significantly different from the random hypothesis (0.05 > P > 0.025) (Fig. 3b). This is not the case for the Large spiders; the distribution of residency times for these is not significantly different from random (0.5 > P > 0.1) (Fig. 3c). For the complete data set see Smith 2006b.
Seasonality of spider relocations.--Summer and autumn are shown to be the peak seasons for beginning a period of residence (Table 2a); spring and summer are the peak seasons for leaving (Table 2b). Winter is a period of relatively low mobility, at least for spiders arriving into a new web site.
The average residence time of 24.9 nights for P. noblei (spiders of all instars) in the short-term observations is just slightly shorter than the residence time of adult females of Cyclosa octotuberculata Karsch 1879 (26.3 days, Nakata & Ushimaru 2004). The residence time of a wide variety of spiders is shown in Table 1 in order of increasing length, and both of these species fit in towards the bottom of the table, i.e. they have long average residence periods. The figures for Poltys were calculated in a similar way to the majority of the species sh