6 

 The antennae of male mosquitoes is such that resonant vibration occurs with female 



wingbeat frequency; the shaft of the antennae transmit the vibration to the 



Johnston's organs. Directional information is most likely acquired from sound due 



to a triangulation method with the antennae. Depending on the phase offset of 



vibrations on each antennae, it is postulated that mosquitoes can determine whether 



the sound is originating within or outside of a 30 degree arc of their flight path line 



[4]. Thus, their approach to a stimulus follows a zig-zag pattern [9]. Additionally, 



mosquitoes fly at approximately one meter per second when in a controlled flight 



toward a host and up to eight meters per second maximum [2,9]. 



One final note on the sensory capacity of the PNS: in a study of 

 Toxorhynchites brevipalpis, there were 622 neurons forming the PNS, not including 

 photoreceptors. Mechanoreceptors attributed for 526 of the neurons, and 

 chemoreceptors made up the final 96 neurons. Most of the mechanosensilla (500 of 

 526) were body setae. 

 Mosquito vision 



The discussion in this section will focus mainly upon the eyes as sensilla 

 pertaining to Ae. aegypti. In the larval stage, two types of eyes are present, the 

 lateral ocelli and the developing adult compound eyes [4]. The ocelli are separated 

 into two dorsal ocelli, a central ocellus, and a ventral ocellus. The ocelli contain 

 cells to gather light and transmit the visual information to the brain via 

 photosensitive nerve cells. Rhodopsin is the visual pigment in mosquito vision; the 

 An,3x for absorption is 515 nm. TTiis corresponds to a visual range of 323-631 nm with 



