The mosquito female appendages that detect volatile compound odors include surfaces on head antennae, palps and labella. Hair sensory neurons on such appendages express olfactory, ion and gustatory protein membrane receptors . Each olfactory neuron expresses one specific odor-receptor (OR) often complexed to one common co-receptor (ORCO). For example, females contained ~ 1130 neurons per antenna (64 % of which were ORCO +ve ), ~ 243 neurons per maxillary palp (38 % ORCO +ve ) and ~ 153 neurons per labella (73 % ORCO +ve ) . Legs, wings and ovopositor also contained receptors but most of them are ORCO -ve 2 . In addition to detecting odors, ORCO -/-mutants have unexpectedly shown that ORCO also interferes with mosquito reproduction . Thus, embryo malformations, lower fertility cycles, reduced percentages of egghatching and/or alterations in the expression of ion channel signalling genes, have been described in ORCO -/-mutants 3 . All those implications make ORCO an exceptional multitarget to interfere with mosquito bites and reproduction.