ecies 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 intraspecific variation is likely to be important for the effective camouflage of spiders in the field.
Short-term observations of residence time.--Three periods of overnight transects were undertaken, an 8-night pilot study during autumn 2000, then 10-night periods in spring 2002 and autumn 2003. The sites were all located in the northern Sydney area, two in the Ku-ring-gai Chase National Park (Myall Track [33[degrees]40'18"S, 151[degrees]08'06"E], and Resolute Picnic Area on West Head [33[degrees]34'50"S, 151[degrees]17'05"E]) and one on the Waitara Creek Fire trail ([33[degrees]42'51"S, 151[degrees]05'23"E] the site detailed under "Long-term observations" below). Each transect route was surveyed several times through the night from dusk to daylight and the positions and activities of Poltys specimens were recorded on each pass. Web details and damage were also recorded as additional information. Following individuals at regular intervals from sunset to sunrise minimized the possibility that spiders were swapping sites without my knowledge since spiders are usually sedentary during the day. Poltys noblei is the only species in the genus recorded from this area (Smith 2006a). Specimens from these sites or close by, examined during the revision of Australian Poltys referenced above, are deposited in the Australian Museum.
[FIGURE 1 OMITTED]
Long-term observations of residence time.--The long-term study was run along 400 m of the Waitara Creek fire trail, a remnant of urban bushland connected to the Berowra Valley Regional Park, between Hornsby and Normanhurst in the northern fringes of Sydney. This site was surveyed at approximately 7-10 day intervals from April 2002 to April 2004 (112 transects at an average of 8.49 day intervals) and then observations were continued on just a few selected spiders until the last had disappeared in late November 2004. Transects were started at least one hour after dark, later if possible to ensure that most specimens had already made webs, and generally on nights with suitable weather condit