Abstract
Exposure to wave action can affect the feeding appendages (cirri) and penis morphology of intertidal barnacles. We tested several hypotheses of morphological differences in the cirri and penises of the barnacle Tetraclita stalactifera at different heights of the intertidal zone, on wave exposed and wave protected sites and at different levels of crowding. We sampled eight sites varying for these properties and found that barnacles from higher positions in the intertidal zone had thicker cirri than those from lower positions. In wave exposed sites, cirri were shorter and thicker than in protected sites. Increased thickness may be an adaptation to reduce risk of breakage in rough environments or in areas with stronger waves (like high positions on rocks). Longer cirri may serve as an adaptation to improve food capture in lower-flow environments. Penises from wave-exposed sites and from higher positions in the intertidal zone were thicker than those from calm areas or from low positions. Thicker penises are likely stronger and reduce the risk of breakage. None of the variables changed with crowding. Our observations of differences in cirri and penis morphology between calm and rough sites suggest that these traits (observed in several barnacle species) are adaptations shared by the species Tetraclita stalactifera. Our observations of differences in those traits with respect to tidal height are novel and suggest that wave action may be more intense at higher positions. This might be an interesting topic for future research in other species.
Faculty Sponsors
Dr. J. Matthew Hoch
Project Type
Event
Location
Alvin Sherman Library
Start Date
4-4-2014 1:00 PM
End Date
4-4-2014 5:30 PM
The Effects of Wave Exposure, Tidal Height, and Crowding on Cirri and Penis Morphology of the Acron Barnacle, Tetraclita stalactifera
Alvin Sherman Library
Exposure to wave action can affect the feeding appendages (cirri) and penis morphology of intertidal barnacles. We tested several hypotheses of morphological differences in the cirri and penises of the barnacle Tetraclita stalactifera at different heights of the intertidal zone, on wave exposed and wave protected sites and at different levels of crowding. We sampled eight sites varying for these properties and found that barnacles from higher positions in the intertidal zone had thicker cirri than those from lower positions. In wave exposed sites, cirri were shorter and thicker than in protected sites. Increased thickness may be an adaptation to reduce risk of breakage in rough environments or in areas with stronger waves (like high positions on rocks). Longer cirri may serve as an adaptation to improve food capture in lower-flow environments. Penises from wave-exposed sites and from higher positions in the intertidal zone were thicker than those from calm areas or from low positions. Thicker penises are likely stronger and reduce the risk of breakage. None of the variables changed with crowding. Our observations of differences in cirri and penis morphology between calm and rough sites suggest that these traits (observed in several barnacle species) are adaptations shared by the species Tetraclita stalactifera. Our observations of differences in those traits with respect to tidal height are novel and suggest that wave action may be more intense at higher positions. This might be an interesting topic for future research in other species.
