Files in this Data Supplement:

• Supplemental Tables 1-3 - Adobe PDF

• Supplemental Figure 1 (Adobe PDF) -

  Fig. S1. Flow charts depicting the formation of the 21 study groups and the fates of each group’s members. Boxes represent study groups and numbers in parentheses are numbers of spiders.

• Supplemental Figure 2 (Adobe PDF) -

  Fig. S2. The sequence of compounds shown, from top to bottom, is the same sequence as presented in the bar charts in Figs S3-S7. Note that taurine was not detected in any webs of Araneus cavaticus, N-acetylputrescine and putrescine were not detected in webs of Argiope aurantia, and free proline was not detected in webs of Argiope trifasciata. Also, one or more additional compounds went undetected in some web collections or, though detected, were so minor as to not be discernible when so plotted. Remember that feeding group individuals were different from individuals composing the starving group, but all resumed feeding group members were former starving group spiders.

• Supplemental Figure 3 (Adobe PDF) -

  Fig. S3. Absolute (top) and relative (bottom) quantities of LMM in water extracts of webs built by Araneus cavaticus juvenile males in feeding and starving/resumed feeding groups. Average desiccated web mass within web collections is indicated by line graphs in the top panels (right y-axis). See Fig. S2 for key.

• Supplemental Figure 4 (Adobe PDF) -

  Fig. S4. Absolute (top) and relative (bottom) quantities of LMM in water extracts of webs built by Araneus cavaticus juvenile females in feeding and starving/resumed feeding groups. Average desiccated web mass within web collections is indicated by line graphs in the top panel (right y-axis). See Fig. S2 for key.

• Supplemental Figure 5 (Adobe PDF) -

  Fig. S5. Absolute (top) and relative (bottom) quantities of LMM in water extracts of webs built by Araneus cavaticus adult females in feeding and starving/resumed feeding groups. Average desiccated web mass within web collections is indicated by line graphs in the top panel (right y-axis). See Fig. S2 for key.

• Supplemental Figure 6 (Adobe PDF) -

  Fig. S6. Absolute (top) and relative (bottom) quantities of LMM in water extracts of webs built by Argiope aurantia adult females in feeding and starving/resumed feeding groups. Average desiccated web mass within web collections is indicated by line graphs in the top panel (right y-axis). See Fig. S2 for key.

• Supplemental Figure 7 (Adobe PDF) -

  Fig. S7. Absolute quantities of LMM in water extracts of webs built by Argiope aurantia and Argiope trifasciata adult females following the construction of first (PES 1), second (PES 2), and third (PES 3) egg sacs. Average web mass within web collections is indicated by line graphs (right y-axis). The collection of webs from the A. aurantia PES 3 group was ended prematurely (see Materials and methods). See Fig. S2 for key.

• Supplemental Figure 8 (Adobe PDF) -

  Fig. S8. Average ranked molar percentages (means ± s.d.) of the 12 LMM in webs of the three study species. Taurine was not detected in any webs of Araneus cavaticus, free proline was not detected in webs of Argiope trifasciata, and N-acetylputrescine and putrescine were not detected in webs of Argiope aurantia. Ala, alanine; Bet, glycine betaine; Cho, choline; GAB, GABamide (4-aminobutyramide); Gly, glycine; Ise, isethionate; NAP, N-acetylputrescine; NAT, N-acetyltaurine; Pro, proline; Put, putrescine; Tau, taurine.

• Supplemental Table 4 - Microsoft Excel

• Supplemental Table 5 - Microsoft Excel

• Supplemental Table 6 - Microsoft Excel