The Mismeasure of Behavior: A Natural History Revision of Prey Preference in the Banded Tulip Snail

Abstract

The banded tulip snail, Fasciolaria (Cinctura) lilium hunteria (Perry), is a predatory gastropod that is capable of subduing a wide range of prey items using multiple attack behaviors. However, the literature contains conflicting accounts of this predator's prey preferences, which vary between the extremes of strong preferences for snails over bivalves to opportunistic behavior in which prey are incorporated into the diet based on their relative abundance in the environment. Here we reexamine the extent to which prey items in the diet of F. hunteria are distributed in preference hierarchies to update the natural history data on this molluscan predator. We tested F. hunteria's preference between oysters, Crassostrea virginica (Gmelin), and snails, Urosalpinx cinerea (Say), two ecologically co-occurring prey items that require different attack behaviors to subdue. Based on cost-benefit analyses, U. cinerea is more energetically profitable than C. virginica, so we predicted that it should be favored by tulip snails. We offered both prey simultaneously to F. hunteria in a Y maze to test this hypothesis. Despite the vast differences between the prey items in terms of potential biomass reward, handling times, and risk to the predator, F. hunteria did not prefer either C. virginica or U. cinerea, live or crushed. Our results suggest F. hunteria has no strong preferences among prey items in its diet, and is an opportunistic predator. This study is an example of the necessity of revising natural history information at a time when accumulation of such data is declining. In light of our results, we discuss the importance of examining the sources of natural history information, and of considering the time period and theoretical framework in which natural history data were gathered and interpreted to prevent cascading error effects resulting from the use of flawed natural history observations.