ABSTRACT.Host‐seeking behaviour in newly emergedAedes aegypti(L.) females is not expressed immediately after adult eclosion but develops gradually over a period of approximately 3–4 days. This development is accompanied by an apparent maturation of the antennal chemosensory afferent neurons involved in the detection of the airborne host attractant lactic acid. Since these events coincide in time with juvenile hormone‐dependent previtellogenic ovarian growth and since the expression of other reproduction‐associated behaviour has previously been shown to be dependent on juvenile hormone, the effects of juvenile hormone removal and replacement on the development of host‐seeking behaviour and the response characteristics of the lactic acid‐sensitive receptors were investigated. No effect of juvenile hormone removal by allatectomy or juvenile hormone replacement or augmentation by topical application of the juvenile hormone mimic methoprene was found. It was concluded that this hormone is not involved in the appearance of host‐seeking behaviour or the apparent maturation of the lactic acid receptors that occurs during early