Predation efficiency of indigenous larvivorous fish species on Culex pipiens L. larvae (Diptera. Culicidae) in drainage ditches in Argentina.

GERARDO A. MARTI; M. DE LAS MERCEDES AZPELICUETA MARÍA; CECILIA TRANCHIDA; SEBASTIÁN A. PELIZZA; JUAN J. GARCÍA

journal of vector ecology

Society for Vector Ecology

Año: 2006 vol. 31 p. 102 - 106

1081-1710

 Two neotropical freshwater fish species, Cnesterodom decemmaculatus (Poeciliidae) and Jenynsia multidentata (Anablepidae) were collected from man-made ditches, a common habitat of the house mosquito Culex pipiens in La Plata, Argentina. Cnesterodom decemmaculatus was recorded in 62 of the 100 examined ditches whereas J. multidentata was collected only from 21 ditches sympatrically with C. decemmaculatus. Culex pipiens was the only mosquito species collected, its larvae and pupae were collected in 38 of the 100 ditches. Fish and mosquito larvae and pupae were collected together in only two ditches and were significantly negatively associated. Siphons of larval Culex and remnants of chironomid larvae, copepods, aquatic mites and fish were present in the gut contents of two C. decemmaculatus from mosquito-positive ditches, while diatoms and filamentous algae were recorded in every fish dissected. Adult C. decemmaculatus and J. multidentata needed approximately 6.20 hours to completely digest one Cx. pipiens IV instar larva under laboratory conditions. When fish were confined with a density of 60 or fewer Cx. pipiens IV instar larvae, C. decemmaculatus and J. multidentata adults consumed 100% within one day, but only 35% and 42%, respectively, when confined with 150 larvae. Eradication of Cx. pipiens from a ditch, where densities had averaged 250 immatures per dip, was achieved 17 days after the introduction of 1,700 C. decemmaculatus.