c 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 conditions for locating spiders. The details of each Poltys seen along the route were recorded. The temperature was noted at the beginning of each survey, at the turn-around point, and again on return to the start. Because of public access to the area and not wishing to draw the attention of potential bird predators to the locations of spiders, web locations were not marked and I avoided seeking out the specimens during the day (although a few were easily visible, which allowed further confirmation that the same specimen was using the site throughout the putative period of residence). Instead, web locations were described or sketched in relation to vegetation features. No attempt was made to mark specimens for a number of reasons (see below), but abdominal shape was noted. The approximate size of each specimen was estimated by eye, without the aid of templates; hence the size ranges used in the analysis are approximate. Slight changes in web site within the same bush or tree (up to about 20-30 cm for a small spider or 50-100 cm for a larger specimen) were noted but were not considered moves unless there were other reasons to suspect that the specimen in the new site was not the original, or that the specimen was now using a different resting position.
Although the long term transects were initiated after only the pilot study of the short term surveys was completed, the further 10-day short term studies confirmed that these observations were valid. Overall, the short-term observations were found to indicate that (i) many spiders use the same, or a closely adjacent, web site night after night; and (ii) the likelihood of a similarly sized and shaped spider moving into a vacated web site soon after departure of the first was small unless there was a high local population density. Therefore, it was indicated that in general it was possible to monitor individual spiders without marking them, even though this introduced a small amount of uncertainty into the results. Marking spiders was decided to be unsuitable for this study