Subaerial naticid gastropod drilling predation by Natica tigrina on the intertidal molluscan community of Chandipur, Eastern Coast of India

• Reports of subaerial naticid foraging are common, but lack proper quantification.
• Detailed analyses of subaerial hunting by Natica tigrina have been done from India.
• N. tigrina opportunistically attacked both epi- and infaunal prey.
• Intensity of drilling predation (DF) on the molluscan assemblage was high (25.7%).
• Strong site and size stereotypy indicated efficient predation by N. tigrina.

Chandipur intertidal flat in eastern coast of India is a killing field. The vast stretch of intertidal habitat opens up during the low tide, and is monopolized by a single naticid species which preys extensively on intertidal taxa. The predator, Natica tigrina, wades through the soft sediments and ambushes on epi- or infaunal prey.There were reports on naticid subaerial hunting, where the workers made vivid observations, but only in few instances quantified different aspects of predation. Detailed quantitative analyses of the present study revealed that N. tigrina attacks opportunistically on all infaunal and epifaunal intertidal bivalve and gastropod prey taxa. Drilling frequencies ranged from 9.70% to 67.67% with no apparent relation with relative abundances of the taxa. High drilling frequency on conspecific predation perhaps suggested elimination of the potential competitor as well as a profitable prey. Behavioral data of predation, i.e., stereotypy of site and size of drillholes on prey shells and low prey effectiveness indicated that the predator was highly efficient.