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Prevalencia de parásitos nematodos Strongylidos asociados al ABSTRACTObjectives. To establish the presence and prevalence of Strongylida nematode parasites in Achatina fulica in the Valle del Cauca, especially of nematodes that are potentially pathogenic for humans. Materials and methods. A. fulica individuals were collected in nine cities of the Valle del Cauca, Colombia. Direct visual examination was used to identify A. fulica parasites. Nematodes were separated from tissue or collected from mucus, washed in saline solution, and fixed in a hot AFA solution. Samples were mounted in glycerine and observed under the microscope. Results. The general nematode parasite prevalence was 35% in 2013. The city with highest prevalence during 2013 was Cartago (60%), following by Buenaventura (42.9%) and Cali (33%), while during 2014 were Cali (30%) and Buenaventura (30%). The Strongylida nematodes registered were classified in three genera: Angiostrongylus (14.7% prevalence), Aelurostrongylus (2.6%),and Strongyluris (2.6%). The city with highest positive records of Angiostrongylus was Cali during 2014 and Aelurostrongylus was Buenaventura during 2013. Strongyluris genus was recorded only in Cali during 2013, with a prevalence of 11%. Of the nine evaluated cities, five has presence of Angiostrongylus. Conclusions. Three genera of Strongylida nematode were recorded associated with A. fulicas specimens in the Valle del Cauca during 2013 and 2014. Therefore, the role that A. fulica and native mollusk species could be playing in the life cycle of these parasites at the local level should not underestimated.

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Objective. To evaluate the intrapopulation genetic variation of A. fulica in the Valle del Cauca. Materials and methods. Ten microsatellite loci from specimens collected at eight municipalities in the Valle del Cauca Department were amplified. Allelic frequencies and descriptors of intrapopulation genetic diversity were estimated. Bayesian analysis was used to estimate the number of groups present in the study area. Results. Two groups were identified in the Valle del Cauca (p > 50%): one group comprised individuals from the north and center of the department, and one group comprised individuals from the south and west of the department. These groups were genetically different from each other (F ST 0.16; p<0.05). Isolation by distance was confirmed (Mantel p 0.01; R 2 0.06), and a high level of endogamy was detected through a deficit of heterozygotes in the evaluated loci (F IS 0.45). Conclusions. We suggest that the A. fulica population present in the Valle del Cauca could have been introduced at more than one location, or that there could have been more than one wave of invasion. The high level of endogamy is probably the result of control activities that eliminated adult individuals in the population, which has led to an enhanced founder effect.Keywords: Endogamy, invasive species, population genetics, Mollusca (Source: CAB). RESUMENObjetivo. Evaluar la variación genética intrapoblacional de A. fulica en el Valle del Cauca. Materiales y métodos. Se amplificaron diez loci microsatélites de muestras obtenidas en ocho municipios del Departamento. Se estimaron las frecuencias alélicas y descriptores de la diversidad genética intrapoblacional y se discriminó mediante un análisis bayesiano la cantidad de agrupaciones presentes en la zona de estudio. Resultados. Se identificaron dos agrupaciones en el Valle del Cauca (p>50%): una conformada por los individuos de los municipios del Norte y Centro, otra por los municipios del Sur y Occidente. Estas agrupaciones, fueron genéticamente diferentes (F ST 0.16; p<0.05), confirmándose además aislamiento por distancia (Mantel p 0.01; R 2 0.06) y un alto nivel de endogamia a partir del déficit de heterocigotos en los loci evaluados (F IS 0.45). Conclusiones. Se sugiere que la población de A. fúlica en el Valle del Cauca pudo tener más de un lugar de introducción o incluso más de una oleada de invasión. Además, el alto nivel de endogamia probablemente es el resultado de las actividades de control, las cuales eliminan individuos adultos de la población lo que conlleva al incremento de la deriva per se del efecto fundador.Palabras clave: Endogamia, especies invasoras, genética de poblaciones, mollusca (Fuente: CAB).

In Colombia, the control of giant African snail populations (Achatina fulica) has been enforced for the past eight years according to the Environmental, Housing, and Territorial Development Ministry (MAVDT from its initials in Spanish). During this period, the environmental authorities have carried out a series of campaigns for snail eradication and to raise awareness in the general community to involve it in the control of this invasive species. In order to inquire about the perception of the citizens of Cali, Colombia, have of the giant African snail and their role as primary stakeholders in the local control programs, a structured survey was done, and the dependency on the sociodemographic characteristics was established through Fisher’s exact test. 316 people took part in the survey; over 80% of the individuals recognized the giant African snail and their form of control, but over 90% of them did not participate in the control campaigns. The perception of the giant African snail varied noticeably with the respondents’ age and was independent of socio-economic and educational level. In conclusion, it was detected a solid dissociation between people and the actions carried out by the environmental authority. It is recommended to take into account people’s concept of invasive species control in other cities as a fundamental instrument in the construction of a more dynamic and inclusive control model.

Understanding the life-history traits of invasive species can increase the effectiveness of eradication efforts and decrease costs. In the giant African snail Lissachatina fulica, one of the 100 worst invasive species on the planet, age structure can be an important indicator of invasiveness. Here, we associated variation in snail size with variation in weight and shell shape, in an effort to better understand the growth pattern in this species. Our study involved two components: we estimated the allometric relationship between weight and length in a natural population and monitored developmental variation in snail shape, weight, length and nutritional condition (condition factor) in a lab population. The weight and length growth patterns of the lab population were estimated independently using exponential regressions based on weekly measurements; shell shape was quantified using geometric morphometrics. In both populations, we found negative allometry between weight and length, suggesting that snail shells tend to elongate during growth. Geometric morphometrics confirmed this pattern and revealed that the change from a rounded to an elongated shell shape does not occur at a constant pace but during a specific growth interval (i.e. at a shell length of 55–65 mm), which is described in the literature as the size when the animal becomes hermaphroditic. Future studies should test whether the shape change reported here corresponds to the transition to the hermaphrodite age class, and with this in mind, we provide two simple morphological indexes that allow us to characterize shell shape as rounded or elongated. If shell size and shape are indicative of the transition to the hermaphroditism, then our findings can help to place individuals of L. fulica into appropriate age classes, and this will represent a useful baseline for development of eradication policies.

Las poblaciones de las especies invasoras pueden diferir en las características que determinan la intensidad de sus efectos sobre los ecosistemas nativos. El estudio de la variación morfológica aporta información valiosa sobre diferentes procesos evolutivos y ecológicos en las especies. Con el objetivo de evaluar los patrones de variación morfológica del caracol gigante africano (Achatina fulica), una especie invasora presente en el departamento del Valle del Cauca, se colectaron individuos en las zonas urbanas de 4 municipios (Buenaventura, Cali, Tuluá y Cartago). A estos especímenes se les realizó un análisis de morfometría geométrica y clasificación con base en el patrón de coloración. Se encontró que existe variación morfológica significativa dentro de la población, además del patrón de bandas o coloración, con un total de 13 patrones en toda la muestra. Se proponen las condiciones ambientales de cada localidad y los controles realizados por la autoridad ambiental como posibles causantes de la variación. Palabras clave. Estructura etaria. Invasión biológica. Moluscos. Morfología. Patrón de coloración.

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