Buoyancy and Ventilation in Aedes Aegypti (L.) Pupae (Diptera: Culicidae)

Various aspects of buoyancy in Aedes aegypti (L.) pupae were studied. Gas in the ventral air space is necessary for a pupa to be buoyant and maintain its normal position at the air-water interface. Pupae, under conditions of forced submergence, and commonly spontaneously, lose their buoyancy and reach or exceed the density of water. Contact with the atmosphere usually results in an immediate recovery of buoyancy. These changes in buoyancy are considered to be caused by changes in volume and/or gas pressure in the tracheal system. An hypothetical explanation for the observed changes in buoyancy is presented and aspects of the functional and adaptive significance of buoyancy and changes in buoyancy are discussed.