Strobilation in the Chesapeake Bay sea nettle Chrysaora quinquecirrha. I. The effects of environmental temperature changes on strobilation and growth

Abstract

AbstractObservation of Chrysaora polyps taken from the Chesapeake Bay and maintained in the laboratory reveals at least four morphological types of animals, chiefly distinguished by the number of tentacles they bear and the manner of strobilation. All of the types strobilate when warmed after sufficient chilling; several waves of strobilations may result from the initial stimulus. One of the types of Chrysaora polyps was selected for characterization with respect to environmental control of its strobilation behavior. These animals must be chilled for a minimum of seven weeks at 20°C before they are able to respond to warming to 26°C by strobilating; it is proposed that a number of factors accumulate during chilling which enable polyps to strobilate when warmed. The time course of strobilation, including release of ephyrae, appears to be determined by the temperature at which strobilation is initiated.The growth of Chrysaora polyps seems to be regulated by both the exact temperature of the environment and relative changes in environmental temperature.