Predatory behaviors of the buccinid whelk Neptunea arthritica toward gastropod prey

Predators must capture prey. They can engage in active searching and/or sit-and-wait behaviors. Neptunea arthritica uses both behaviors to prey on various animals ranging from sessile to mobile species. This paper describes the repertoire of these behaviors toward mobile gastropod prey at the individual level in the laboratory. We conducted 201 feeding trials and analyzed 451 cases of predation in 107 trials. Active searching was used at least once in 104 trials and sit-and-wait in 67 trials. Individuals often used both behaviors (64/107). Those that used only one behavior (43/107) favored active searching (40/43). Active searching was the most common behavior toward all prey species. This study is the first case in gastropod research to clearly define the two tactics and to quantitatively describe the patterns of tactic use at the individual level. The benefits of using a sit-and-wait tactic against mobile prey are discussed from the perspective of energetic efficiency.