Caracterización del consumo de larvas de culícidos (Diptera) en dos especies de peces indígenas de la zona central de Argentina

Abstract

ABSTRACT. Characterization of Culicidae larvae (Diptera) consumption in two species of native fish in the central zone of Argentina. Mosquitoes represent a threat to human health and animals because they act as vectors of several diseases. Native fish species are potential candidates to be considered for biological control populations of mosquitoes. Tests of half-hour and 24-hour consumption of Culex pipiens (Linnaeus, 1758) larvae by Cnesterodon decemmaculatus (Jenyns, 1842) and Jenynsia multidentata (Jenyns, 1842) were carried out, measuring the standard length, mouth width and weight in individuals of the two species of fishes. In both tests J. multidentata consumed more C. pipiens than C. decemmaculatus, being C. decemmaculatus female consumption higher than male consumption (and equal than both sexes of J. multidentata in the 24-hour test). These results remained unchanged when making comparisons of absolute or relative consumption in the half-hour test, but when consumptions relative to weight were compared no difference between species was found in the 24-hour test. Regression analysis between morphometric variables and weight vs. consumption rates showed low explanatory value for the half-hour test, while in the 24-hour test these variables had higher explanatory value, especially for the mouth width. Finally, a half-hour test was performed over C. decemmaculatus females using C. pipiens and Aedes aegypti (Linnaeus, 1742) larvae and it showed a strong preference for the latter ones. This work allowed us to observe that there are large differences in consumption rates of C. pipiens larvae between the fish species under study in short periods. Differences are attenuated when consumption times are longer and may even disappear when weight is taken into account. KEYWORDS.Cnesterodon decemmaculatus, Jenynsia multidentata, biocontrol, mosquito larvae. RESUMEN.Los mosquitos representan una amenaza para la salud del hombre y de los animales debido a que actúan como vectores de distintas enfermedades. Especies de peces nativos son potenciales candidatos a tenerse en cuenta para control biológico de poblaciones de culícidos. Experiencias de consumo de media hora y de 24 horas por Cnesterodon decemmaculatus (Jenyns, 1842) y Jenynsia multidentata (Jenyns, 1842) se llevaron a cabo con larvas de Culex pipiens (Linnaeus, 1758), midiéndose longitud estándar, ancho de boca y peso en individuos de las dos especies. En ambas pruebas, J. multidentata consumió más C. pipiens que C. decemmaculatus, consumiendo las hembras de esta última especie más que los machos (e igual a ambos sexos de J. multidentata en la prueba de 24 horas de duración). Estos resultados no variaron cuando se compararon tantos consumos absolutos o relativos para las pruebas de media hora, sin embargo cuando se compararon los consumos relativos al peso no se encontraron diferencias entre las especies para las pruebas de 24 horas. Análisis de regresión entre las tasas de consumo versus las variables morfométricas y el peso mostraron poco valor explicati...

Assessment of the predatory capacity on mosquito larvae of Jenynsia multidentata (Anablepidae) in presence of vegetation under laboratory conditions

“…Jenynsia multidentata consumption results obtained by Marti et al (2006) at a density of 60 larvae were like those achieved in this experiment and inferior at a larval density of 120. The results showed that J. multidentata predatory capacity was greater, even in the presence of vegetation, than those obtained by other authors in experiments without vegetation (Marti et al, 2006, Bonifacio et al, 2014. This could be due to the differences in water volume used in both experiments.…”

“…This could be due to the differences in water volume used in both experiments. Lower predatory capacity was observed in J. multidentata females in experiments with small volumes of water (Bonifacio et al, 2014). The fish energy expenditure could decrease with a lower volume of water that, in turn, would reduce the consumption of larvae.…”

“…It is an omnivorous species (Ringuelet, 1967), strongly euryhaline (Baigún et al, 2002) and associated with aquatic vegetation (Escalante, 1983;Menni, 2004;Quezada-Romegialli et al, 2009). The predation capacity of J. multidentata was evaluated under laboratory and field conditions with different results (Marti et al, 2006, Bonifacio et al, 2014, vegetation effect on predation efficiency is an important factor to consider if larvivorous fish are used as biocontrol agents in the environment, and such study has not been carried out in J. multidentata until now.…”