Impacts of Light and Food Availability on Early Development of Cassiopea Medusae

Abstract

The Cassiopea genus is an emergent focus for behavioral, ecological, and genetic research. Cassiopea ephyrae, a key intermediate in the life cycle of this benthic jellyfish, have been left out of much work on the genus. Here we investigate the Cassiopea xamachana ephyra response to six combinations of light and feeding regimes. We show that zero light condition results in fast bleaching of ephyrae and significant reductions in bell size and predation success. We also show that ephyrae starved in sub-compensation level light experienced only meager reductions in size over 42 days, and those starved in zero light were still largely recoverable at 28 days. Developmental trajectories on various metrics of Cassiopea xamachana ephyrae were significantly impacted by both light and feeding level in the first 42 days of life.

Host starvation andin hospitedegradation of algal symbionts shape the heat stress response of theCassiopea-Symbiodiniaceae symbiosis

“…The loss of these structural sugars and proteins, together with their ability to retain water, likely caused water loss and consequently body shrinkage in heat-stressed medusae (Chapman, 1953;Gardner & Zubkoff, 1978;Pedersen & Vilgis, 2019). This hypothesis is corroborated by reports of similar rapid change in the water content of Cassiopea exposed to thermal stresses (Aljbour et al, 2017) and similar shrinkage of Cassiopea and Aurelia aurita ephyrae during starvation without heat stress (Fu et al, 2014;Muffett et al, 2022). Furthermore, the observation of reduced pulsation (Figure 1D) and the onset of host mortality (Figure 1A) implies that our unfed Cassiopea animals were unable to compensate for the metabolic constraints of severe heat stress over extended periods of time, here 7 days.…”

Non-invasive investigation of the morphology and optical properties of the upside-down jellyfishCassiopeawith optical coherence tomography

“…Externally, rhopalia were visible along the bell margin, and the first oral arm bifurcation and groves were clearly visible. Individual arms showed signs of vesicles forming apically, while digitata were not yet present (e.g., Jordano et al, 2022; Muffett et al, 2022) (Figure 1a). The bell-disk surface is not perfectly flat, but appears ridged in a radial pattern, possibly due to the musculature lining the subumbrella epidermis (Blanquet and Riordan, 1981).…”

Non-invasive investigation of the morphology and optical properties of the upside-down jellyfish Cassiopea with optical coherence tomography

“…Individual arms showed signs of vesicles forming apically, while digitata were not yet present (e.g. [ 55 , 56 ]) ( figure 1 a ). The bell-disc surface is not perfectly flat, but appears ridged in a radial pattern, possibly due to the musculature lining the subumbrella epidermis [ 57 ].…”