Two for one: inadvertent introduction of Euglandina species during failed bio-control efforts in Hawaii

Abstract

The introduction of the predatory land snail, Euglandina rosea (Ferrusac, 1821) from Florida to Hawaii to control the giant African snail, Lissachatina fulica (Bowdich, 1822) is among the most publicized biological control cases gone awry. Following preliminary genetic analyses that revealed a second, possibly undescribed Euglandina species was probably introduced to Hawaii, we used an integrative systematic approach combining both genetic and morphological assessments to examine the taxonomic status of the snail referred to as E. rosea in Hawaii. Genetic and morphological analyses support the interpretation that two Euglandina species were introduced to and have become established in Hawaii and can be readily distinguished based on morphological differences. This finding has significant ramifications for understanding both historical and contemporary biocontrol as it suggests that: (1) other species may have been inadvertently introduced through bio-control programs, (2) inadequate understanding of the taxonomy of bio-control agents has obscured our ability to effectively study their ecological impacts, and (3) while the US has no comprehensive regulatory framework for importing biological control agents, one is urgently needed. This also has wide-ranging implications for conservation efforts throughout the tropics because Euglandina from Oahu, Hawaii were released on other Hawaiian Islands, New Guinea, Okinawa, Palau Islands, Philippines, India, Bonin Islands and Bermuda for use in biological control programs that led to catastrophic loss of endemic land snail diversity.