Restricted Genetic Variation in Populations of Achatina (Lissachatina) fulica outside of East Africa and the Indian Ocean Islands Points to the Indian Ocean Islands as the Earliest Known Common Source

Abstract

The Giant African Land Snail, Achatina ( = Lissachatina) fulica Bowdich, 1822, is a tropical crop pest species with a widespread distribution across East Africa, the Indian subcontinent, Southeast Asia, the Pacific, the Caribbean, and North and South America. Its current distribution is attributed primarily to the introduction of the snail to new areas by Man within the last 200 years. This study determined the extent of genetic diversity in global A. fulica populations using the mitochondrial 16S ribosomal RNA gene. A total of 560 individuals were evaluated from 39 global populations obtained from 26 territories. Results reveal 18 distinct A. fulica haplotypes; 14 are found in East Africa and the Indian Ocean islands, but only two haplotypes from the Indian Ocean islands emerged from this region, the C haplotype, now distributed across the tropics, and the D haplotype in Ecuador and Bolivia. Haplotype E from the Philippines, F from New Caledonia and Barbados, O from India and Q from Ecuador are variants of the emergent C haplotype. For the non-native populations, the lack of genetic variation points to founder effects due to the lack of multiple introductions from the native range. Our current data could only point with certainty to the Indian Ocean islands as the earliest known common source of A. fulica across the globe, which necessitates further sampling in East Africa to determine the source populations of the emergent haplotypes.

Variación génica intrapoblacional del caracol gigante africano (Achatina fulica) en el Valle del Cauca

“…Until the present time this species has been recorded in Cuba, Venezuela, Argentina, Paraguay, Ecuador, Peru, and Colombia (1,(3)(4)(5). According to Resolution 0848 of 2008 by the Ministry of Environment, Housing, and Land Development, A. fulica is considered an exotic invasive species in Colombia.…”

“…Sexualmente se consideran hermafroditas protándricos (desarrollan primero el sexo masculino), alcanzan la madurez sexual a los cinco meses y en condiciones óptimas de temperatura, humedad y disponibilidad de alimento pueden colocar ovoposiciones con centenares de huevos (1)(2)(3)(4)(5).…”

“…Hasta la fecha se ha confirmado la presencia de esta especie en Cuba, Venezuela, Argentina, Paraguay, Ecuador, Perú y Colombia (1,(3)(4)(5). De acuerdo con la Resolución 0848 del 2008 del Ministerio de Ambiente, Vivienda y Desarrollo Territorial, A. fulica se considera una especie exótica invasora en Colombia.…”

“…They are considered protandric hermaphrodites (they develop the masculine sex first). Giant African snails reach sexual maturity at five months, and under optimal conditions of temperature, humidity, and food availability, can oviposit hundreds of eggs (1)(2)(3)(4)(5).…”

“…El caracol africano como especie invasora, presenta a nivel genético el mismo comportamiento que las demás especies invasoras (13)(14)(15): una baja en la diversidad génica respecto a las poblaciones en su rango natural de distribución en África, debido al efecto fundador que ocurre en cada evento de introducción, y a los cuellos de botella subsiguientes al establecimiento y aclimatación a las condiciones del nuevo hábitat (1,4). Aunque desde el punto de vista ecológico las poblaciones de A. fulica en las etapas iniciales de invasión pueden considerarse exitosas, cuando la invasión lleva varias décadas la dinámica poblacional tiende a estabilizarse o incluso puede llegar a decaer de forma natural (1,15).…”