Effects of Predator Kairomones and Starvation on Tegula tridentata Behavior in a Chilean Subtidal Ecosystem

Abstract

Gastropods have been shown to alter their behavior in response to both predators and starvation. Tegula tridentata, a marine subtidal gastropod in Chile, is an herbivore that is preyed upon by the crab Homalaspis plana and the sea star Meyenaster gelatinosus. The effects of kairomones (chemicals) from H. plana, M. gelatinosus, and crushed conspecifics as well as the effects of starvation were tested to see if the different treatments elicited behavioral responses by T. tridentata. Three experimental trials were conducted in which T. tridentata behavior was monitored continuously every hour for 24 hours and was then monitored at less continuous but regular intervals for up to 72 hours. Aquaria containing T. tridentata (one per aquarium) were connected to predator treatment aquaria via flow-through systems to allow for kairomones to flow from the treatment aquaria into the T. tridentata aquaria. Different starvation levels were also used alongside the presence of kairomones. T. tridentata behavior and location within the aquarium was recorded during each observation. There was a significant reduction in movement rates and behaviors when T. tridentata were exposed to kairomones from H. plana even when starved for 20 days. These results have potential economical implications as there is a high economic demand in Chile for both kelp that T. tridentata consume and H. plana.