The effects of symbiotic state on heterotrophic feeding in the temperate sea anemone Anthopleura elegantissima

Abstract

The temperate sea anemone Anthopleura elegantissima is facultatively symbiotic with unicellular algae. Symbiotic A. elegantissima can supplement heterotrophic feeding with excess photosynthate from their algal partners, while asymbiotic individuals must rely solely on heterotrophy. A. elegantissima individuals were collected from Swirl Rocks, Washington (48°25Ј6Љ N, 122°50Ј58Љ W) in July 2010, and prey capture and feeding characteristics were measured to determine whether asymbiotic individuals are more eYcient predators. Feeding abilities were then measured again after a 3-week exposure to full sunlight or shaded conditions. Freshly collected asymbiotic anemones had larger nematocysts, but symbiotic individuals showed greater nematocyte sensitivity. Sunlight enhanced digestion and reduced cnida density in all anemones regardless of symbiotic state. Results suggest that the phototropic potential of A. elegantissima, as inXuenced by symbiotic condition, has little eVect on heterotrophic capacity. The anemones appear to maximize heterotrophic energy input independent of the presence or identity of their algal symbionts.

Symbiont type influences trophic plasticity of a model cnidarian–dinoflagellate symbiosis

“…These results are in contrast to those of Hiebert and Bingham (2012), who noted no significant difference in the feeding ability of the temperate anemone Anthopleura elegantissima while aposymbiotic or harboring Symbiodinium or 'zoochlorellae'. While not measured here, it is also possible that symbiont type in Aiptasia affects the anemone's capacity to capture prey through morphological variations such as tentacle number, size or cnida characteristics (Hiebert and Bingham, 2012).…”

“…This may be a consequence of physiological differences among different host genetic lines. Different lines of anemones may have physiological differences that slow down digestion or different morphological features, as previously detailed, that increase prey capture rate (Hiebert and Bingham, 2012). In contrast, as the same host line was used in all anemones apart from strain 3, the increased prey ingestion with slower digestion in aposymbiotic and D4-5 anemones is associated with the absence of symbionts or the type of symbiont, respectively.…”

“…2B) may justify their slow digestion rates (supplementary material Table S2), the similarity between the aposymbiotic and clade D-harboring anemones may also be explained by the reduced autotrophic contribution of D4-5 symbionts to support host metabolism and, particularly, physiological costs associated with prey digestion (Sebens, 2002). These results are in contrast to those of Hiebert and Bingham (2012), who noted no significant difference in the feeding ability of the temperate anemone Anthopleura elegantissima while aposymbiotic or harboring Symbiodinium or 'zoochlorellae'. While not measured here, it is also possible that symbiont type in Aiptasia affects the anemone's capacity to capture prey through morphological variations such as tentacle number, size or cnida characteristics (Hiebert and Bingham, 2012).…”

Effect of symbiotic state on the fatty acid composition of Anthopleura elegantissima

“…It is unlikely that feeding varied between anemones in different symbiotic states because we collected all sea anemones from the same site and at approximately the same tidal height. In addition, A. elegantissima symbiotic state has little effect on heterotrophic feeding (Hiebert and Bingham 2012), implying that the concentration of lipids acquired from the diet should be homogenous across symbiotic states. However, whether symbiont identity or presence influences host feeding should be further explored.…”

Diet of the sea anemone Anthopleura nigrescens: composition and variation between daytime and nighttime high tides

“…Sea anemone digestion rates depend on the type of prey, the size of the prey items and the anemone species. However, the average digestion time of the temperate species Anthopleura elegantissima is 8 to 9 hours (Hiebert and Bingham 2012) and previous studies show that digestion rates are faster at higher temperatures and with exposure to sunlight (Kruger and Griffiths 1997;Rossi et al 2004;Purcell 2009;Hiebert and Bingham 2012).…”