Adler et al. American Journal of Botany

Adler et al.—American Journal of Botany 2016. DOI: 10.3732/ajb.1600114 – Appendix S1

Appendix S1. Comparative study of floral traits and interactions in north and south Georgia.
Methods. In 2004, we surveyed nectar robbing and florivory on 10 naturally growing plants per site at six sites (60 plants total) in north Georgia on 7-Apr-04 and from 108, 18 and 23 naturally growing plants (149 plants total) from three sites in south Georgia from 25-31 Mar-04. The north and south Georgia sites were located near the University of Georgia Botanical Gardens in Athens, GA (33.902065 N, -83.387460 W; Clark County) and the Georgia Southern University Botanical Gardens in Statesboro, GA (32.420422 N, 81.773772 W; Bulloch County), respectively. Nectar robbing and florivory were assessed on all open flowers on each plant. Robbing was measured as described in the methods of the main manuscript. For flowers with florivory, we counted them relative to the number of flowers open and estimated the percentage of floral tissue removed. Both antagonists produced easily identifiable, characteristic damage. Data are summarized as the percentage of plants with any robbing or florivory damage per site and, for plants with damage only, as the proportion of flowers per plant that were robbed or had florivory (averaged across sites).

Leaf and flower gelsemine was also measured for Gelsemium in south Georgia, to compare to published values for north Georgia plants. Up to 29 flowers and 50 leaves per plant (43 plants for leaf samples, of which 33 also had sufficient floral material for analysis) were collected on 31-Mar-03 from the largest of the three populations where interactions were recorded. Samples were stored, extracted and analyzed as in methods in the main text. Gelsemine values for north Georgia are those published in Irwin and Adler (2006), which were collected from 5 sites in north Georgia in 2002 for a total of 83 leaf samples and 28 flower samples. Note that the published North Georgia values excluded samples in which no gelsemine was detected; these were typically samples in which we collected insufficient tissue (mean of 0.075 g of flower tissue/sample and 0.423 g of leaf tissue/sample and mean of when our goal was 0.5 g/sample) and suspected the values represented amounts below our detection threshold rather than true zeroes. If we included these zero values, the gelsemine values for North Georgia would be 63.93 +/ 13.98 SE (N = 64) for corolla gelsemine and 250.57 +/- 34.27 SE (N = 87) for leaf gelsemine.

Floral morphology and nectar data are provided for comparative purposes by averaging values for pin and thrum morphs from previously published work. Floral data for north Georgia are from 90 plants from five populations measured in 2002, which included 65 plants for nectar volume and 37 for nectar sugar (Irwin and Adler, 2006), and data for south Georgia are from 36 plants (morphology) or 18 plants (nectar) from two populations measured in 2000 (Leege and Wolfe, 2002).
Table 1. Biotic interactions and gelsemine concentrations in Gelsemium from north and south Georgia. Values are means (range) for proportion of plants with robbing or florivory per site, and means + s.e (averaged over all sites) for proportion of flowers per plant with robbing or florivory and for gelsemine concentrations. Note that proportion of flowers per plant with robbing or florivory was calculated only for plants that received damage.

	Trait	north GA	south GA
Interactions	% plants robbed	43.4% per site (10-70%)	7% per site (0-21%)
	% plants with florivory	13.3% per site (10-20%)	36% per site (28-43%)
	Prop. of flowers with robbing	49.5 + 0.06%	25.2 + 0.06%
	Prop. of flowers with florivory	26.1 + 0.05%	26.5 + 0.03%
Defense traits	Leaf gelsemine	^†268 + 35 ug/g	861 + 119 ug/g
	Flower gelsemine	^†170 + 27 ug/g	186 + 26 ug/g
Floral traits	Corolla length	^†22.7 + 0.2 mm	^§27.5 + 0.3 mm
	Corolla width	^†13.1 + 0.2 mm	^§11.1 + 0.4 mm
	Nectar volume	^†1.1 + 0.1 µl	^§14.2 + 1.5 µl
	Nectar sugar ^a	^†48.2 + 1.4 %	^§23.9 + 2.4 %

Notes:

^a Nectar volumes for North Georgia are in µl/48 hr after opening. For South Georgia, values are standing crop in fully open flowers, which was typically 2-3 days after initial opening (Leege and Wolfe 2002)

^† from Irwin and Adler 2006

^§ from Leege and Wolfe 2002
LITERATURE CITED

Irwin, R. E., AND L. S. Adler. 2006. Correlations among traits associated with herbivore resistance and pollination: implications for pollination and nectar robbing in a distylous plant. American Journal of Botany 93: 64-72.

Leege, L. M., AND L. M. Wolfe. 2002. Do floral herbivores respond to variation in flower characteristics in Gelsemium sempervirens (Loganiaceae), a distylous vine? American Journal of Botany 89: 1270-1274.