An ovitrap (BR-OVT) based on physical and chemical stimuli for attracting gravid
Culex quinquefasciatus (Diptera: Culicidae) females was developed and evaluated under laboratory and field conditions. Attractants
were assayed using alternative chamber bioassays prior to being used in the BR-OVT oviposition trap. A significant
preference of gravid females for sites containing conspecific egg rafts was observed, as a response to
the natural oviposition pheromone, as well as for sites treated with the synthetic pheromone erythro-6-acetoxy-
5-hexadecanolide. Five- to 20-day old grass infusion was strongly attractive to gravid females for laying
eggs. On the other hand, entomopathogenic
Bacillus sphaericus
(
Bs) did not influence the choice of an oviposition site when used in combination with grass infusion and can therefore be used as a larvicide in ovitraps.
Results from field trials showed that the BR-OVT with grass infusion and with or without
Bs works as a preferred
oviposition site for
Cx. quinquefasciatus. The BR-OVT was more effective for egg collection when placed
indoors and comparison with the number of egg rafts laid in cesspits over 40 days indicates that this very simple
ovitrap may be a useful tool for monitoring populations of the most important of the vectors of bancroftian filariasis.
