Physiology of accessory pulsatile organs: Hemolymph circulation in the mosquito antennae

Hemolymph propulsion across the insect hemocoel is primarily driven by the contractile action of the dorsal vessel.  Although effective in circulating hemolymph across the central body cavity, this pump does not produce sufficient force to propel hemolymph into some extracardiac areas.  To overcome this limitation, insects have evolved accessory pulsatile organs (APOs) that drive hemolymph through appendages and the ventral extracardiac space.  In the present study we used fluorescence-based intravital video imaging and histology to characterize the antennal accessory pulsatile organs of the mosquito, Anopheles gambiae (Diptera: Culicidae).  We will present data that (1) characterize the contraction rate of mosquito antennal APOs, (2) show that the antennal APOs and the dorsal vessel (heart) contract independently, (3) measure the directional velocity of hemolymph as it travels across the antennal space, and (4) describe the structure of the antennal APOs and the antennal vessel.