Results and Discussion
GrowthEavesdropping did not appear to have an effect on algal growth. There was no difference in growth between DMS and control algae for the 0-day, 1-day, or 3-day cultures.
HerbivoryEavesdropping did not appear to have an effect on herbivory. There was no difference in the percent area grazed between DMS and control algae for the 0-day, 1-day and 3-day cultures.
ConclusionsOur results suggest that Lacuna vincta may not be deterred by DMS. While deterring effects of DMS and acrylic acid have been observed for Strongylocentrotus droebachiensis (Van Alstyne and Houser 2003), Lacuna vincta have been found to preferentially graze Ulva lactuca compared to other macroalgae due to the higher nutritional value of U. lactuca (Chavanic and Harris 2002; Van Alstyne et al. 2009). The preference of L. vincta for U. lactuca, as well as the fact that L. vincta often deposit their eggs on U. lactuca, may suggest that both species may have coevolved. Coevolution of U. lactuca and L. vincta would explain the disregard of L. vincta to the chemical defenses of U. lactuca and why L. vincta would not be deterred by the elevated DMSP levels in eavesdropping algae.
ReferencesChavanich S and Harris LG (2002) The influence of macroalgae on seasonal abundance and feeding preference of subtidal snail, Lacuna vincta (montagu) (Littorinidae) in the Gulf of Main. J. Mollus. Stud. 68: 73-78
Van Alstyne, KL, and Houser LT (2003) Dimethylsulfide release during macroinvertebrate grazing and its role as an activated defense. Mar Ecol-Prog Ser 250: 175 181
Van Alstyne KL, Pelletreau KN, Kirby A (2009) Nutritional preferences override chemical defenses in determining food choice by a generalist herbivore, Littorina sitkana. J Exp Mar Biol Ecol 379:85-91