Biología de las larvas de Rhantus signatus (Coleoptera: Dytiscidae) y su asociación con larvas de culícidos en Buenos Aires

MICHAT, M. C.; TORRES, P. L. M.; SCHWEIGMANN, N.

Vaquerías, Valle Hermoso, Córdoba, Argentina

Jornada; ACTAS II Jornadas Regionales sobre Mosquitos 2001; 2002

Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba. Centro de Investigaciones Entomológicas de Córdoba. Facultad de Ciencias Médicas

Rhantus signatus is an aquatic coleopteran whose predaceous larvae inhabit many aquatic environments of Buenos AiresCity.In this work we studied some ecological aspects of these larvae, and its association with preimaginal culicids. Between 1998 and 2001 the temporary rain pools, shallow lakes and permanent ponds (with artificial shore) of Buenos Aires were surveyed. Samples were taken with a hand net or plastic recipients; in the pools, the surface area, depth and substrate vegetation cover were also measured. Ditiscid larvae were present around the whole year in the pools. On the other hand, in the shallow lakes they were only detected in winter and spring, and in the ponds they were not present, probably conditioned by predation. We observed an increment of pools with larvae at increasing depth and surface area, and at intermediate substrate vegetation cover. Increasing depth and surface area would be related to greater duration, thus allowing the larvae to complete their aquatic development. Mosquito immatures were present in 77% of the pools where ditiscid larvae were recorded. The scarce relationship between the seasonal fluctuations of both groups may be explained by the generalist character of these predaceous larvae, and by the presence of alternative prey.