Population dynamics and reproductive biology ofAchatina fulica Bowdich, 1822 (Mollusca, Gastropoda) in Salvador - Bahia

Abstract

Abstract:The risks following introduction of invasive species are enormous and incalculable. Achatina fulica is considered one of the 100 species of greatest invasive potential, stands out among the land pulmonate snails, mostly for its high reproductive potential that accelerates the process of dispersion, increasing the damages related to health (disease transmission), to economy (crops destruction) and to environment (biodiversity loss). In order to investigate the relationship of the African snail with the environment, trying to relate sexual activity with climatic variables (temperature, rainfall and humidity), a study was conducted on aspects of population dynamics and reproductive biology in Salvador city. The snails were collected by hand, monthly. Morphometric data were obtained in the field and dissections to analyze the reproductive system at laboratory. To test if there was a greater sexual activity in wet periods was performed first a Principal Component Analysis (PCA) with climatic variables, followed by a regression between precipitation (the most influential environmental variable) and the variable of interest (sexual activity). The results showed that there is an apparent annual cycle for A. fulica, with a recruitment period covering the end of rainy season and the dry season (August to December 2006 and February 2007). Increase of shell size (height) and of sexual activity were observed during the rainy season, although snails were found in full sexual activity during the whole period of study. The von Bertalanffy curve showed that the oldest specimen collected would have three years and eleven months. The regression between precipitation and sexual activity was significant (P = 0.002) showing that the higher rainfall increased sexual activity. In addition, it was observed that there is an increase in the thickness of peristome as the specimens reaches sexual maturity however this relationship isn't precise (it were found individuals with sexual structures not consistent with the reproductive stage given by the thickness of peristome) and should be set for each region studied. As the eradication becomes impossible because of high level of invasion found in Salvador, it is recommended to control the population of African snails by continuously removing specimens, especially in the rainy periods. Keywords: bioinvasion, invasive species, reproductive cycle, growth, giant African snail.SILVA, E.C., OMENA, E.P. Dinâmica populacional e biologia reprodutiva de Achatina fulica Bowdich, 1822 (Mollusca, Gastropoda) na cidade de Salvador -Bahia.http://dx. doi.org/10.1590/1676-0603000414Resumo: Os riscos com a introduçã o de espécies invasoras sã o enormes e incalculá veis. Constando como uma das 100 espécies de maior potencial invasor, Achatina fulica se destaca dos demais gastrópodes pulmonados terrestres, principalmente, pelo seu elevado potencial reprodutivo que acelera o processo de dispersão, aumentando os danos relacionados à saúde (transmissão de doenças), à economia (destruição de cultivos) e ao ...

Notes on a population of Columella edentula (Gastropoda: Pulmonata: Truncatellinidae) at a sedge meadow in Western Poland

“…The stimulating effect of the rainfall in land snails' reproduction was previously described in other species (e.g. Pollard 1975;Tompa 1984;Silva and Omenta 2014).…”

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

“…Atributos como la alta tasa reproductiva, pocos requerimientos de hábitat, ser un competidor superior y tener una alta facilidad de transporte por el ser humano, posicionaron al caracol africano como una de las 100 especies invasoras más peligrosas a nivel mundial (6)(7)(8)(9). Desde su salida del rango natural de distribución en África hace 200 años, esta especie ha ocasionado una gran variedad de daños ambientales y de salud pública al ser hospedero intermediario de diferentes especies parásitas como los nematodos del género Angiostrongylus, los cuales ocasionan muertes por meningitis eosinofílica.…”

“…Desde su salida del rango natural de distribución en África hace 200 años, esta especie ha ocasionado una gran variedad de daños ambientales y de salud pública al ser hospedero intermediario de diferentes especies parásitas como los nematodos del género Angiostrongylus, los cuales ocasionan muertes por meningitis eosinofílica. Además, esta especie puede llegar a provocar importantes pérdidas económicas al afectar cultivos agrícolas y requerir altas inversiones para implementar las medidas de manejo, control y erradicación (1,9,10). Estos impactos directos e indirectos de A. fulica sobre la salud humana y la economía de las regiones que invade han sido el principal motor para la investigación a nivel ecológico, fisiológico y genético del molusco, con el fin de obtener las herramientas necesarias para fortalecer los planes de manejo e incluso poder proponer medidas de aprovechamiento integrado de la especie (9)(10)(11).…”

“…Attributes such as having a high fertility rate and few habitat requirements, being a superior competitor easily transported by humans, and being economically attractive, placed the African snail as one of the 100 most dangerous invasive species worldwide (6)(7)(8)(9). Since its departure from its natural distribution range in Africa 200 years ago, this species has caused a wide variety of environmental damage and public health issues because it is an intermediary host in the life cycle of several parasitic species, such as nematodes of the Angiostrongylus genus, which cause death in humans from eosinophilic meningitis.…”

“…Since its departure from its natural distribution range in Africa 200 years ago, this species has caused a wide variety of environmental damage and public health issues because it is an intermediary host in the life cycle of several parasitic species, such as nematodes of the Angiostrongylus genus, which cause death in humans from eosinophilic meningitis. Furthermore, this species can lead to significant economic losses by affecting agricultural crops and requiring high investments to implement management, control and eradication measures (1,9,10). These direct and indirect impacts of A fulica on human health and the economy of the regions, have provided the impetus for research into the ecology, physiology and genetics of this mollusk, to obtain the necessary tools to strengthen management plans and propose integrated exploitation measures for this species (9-10).…”