Figure 2.

Morphological differences between types of the snail Littoraria irrorata. J-snails (light gray diamonds) were collected from the host plant Juncus roemerianus; S-snails (dark gray circles) were collected from the host plant Spartina alterniflora. If there was a significant difference in slope between snail types, the relationship between each morphological trait and shell size is represented by solid gray and dashed black lines for S-snails and J-snails, respectively; if there was no significant difference in slope between snail types, the relationship is represented by a solid black line. The relationship between snail shell length in mm and (A) shell width in mm (S-snails and J-snails: y = 0.44x + 4.30, R² = 0.52, P < 0.001); (B) mean ridge thickness in mm (J-snail: y = 0.13x − 0.77, R² = 0.66, P < 0.001; S-snail: y = 0.05x + 0.83, R² = 0.22, P = 0.01); (C) aperture ratio (length:width) (S-snails and J-snails: y = −0.01x + 1.61, R² = 0.04, P = 0.14). (D) aperture length in mm (S-snails and J-snails: y = 0.18x + 3.40, R² = 0.27, P < 0.001). (E) aperture width in mm (S-snails and J-snails: y = 0.17x + 1.77, R² = 0.30, P < 0.001). Shell characteristics defined as in Moody and Aronson (2012) and Bourdeau (2009).