Spider web construction is energetically costly, but it plays an important role in survivorship and reproduction. Studies have revealed facultative changes in spider web construction to adjust to available attachment sites. We used rectangular cardboard frames and two contrasting substrates to determine preferences in placement of gumfoot lines. This study demonstrated that mature females and first-instar nymphs of the brown widow spider, Latrodectus geometricus, display preferences for smooth substrates as sites to attach the gumfoot lines of their webs. First-instar nymphs also preferred to attach to the peaks when offered a wrinkled substrate. The preference of first-instar nymphs supports the hypothesis that substrate preferences for gumfoot line attachment may already be a selected behavior and not learned from previous experience.