Chemical defense, biochemical composition and energy content of three shallow-water Antarctic gastropods

摘要

Aqueous extracts of the mantle tissues of the opisthobranchsAustrodoris kerguelensisandTritoniella belliand the lamellarid gastropodMarseniopsis molliswere cytotoxic to the sperm of the antarctic sea urchinSterechinus neumayeri, and caused behavioral responses (sustained terminal sensory tube-feet retractions) in five species of antarctic sea stars. Pieces of mantle tissue of all three species were noxious to two species of antarctic fish. Primary body components (mantle, foot, viscera) of the three gastropod species contained high levels ( dry wt) of NaOH-insoluble protein (40–59), moderate levels of NaOH-soluble protein (7–25) and lipid (6–18), and low levels of carbohydrate (<1). The energetic composition of the tissues reflected their organic make-up, with most energy (11–17 kJg−1dry wt) associated with protein. Total energy contents of representative adult individuals were 192,26 and 69 kJ forA. kerguelensis(93 g wet wt),T. belli(22 g wet wt) andM. mollis(114 g wet wt), respectively. Although these sluggish gastropods lack an external shell and are nutrient-and energy-rich and therefore high quality prey, like many of their temperate and tropical counterparts, they appear to be protected by