4 

 females for mating. Additionally, differences exist among species as to preference 



of hosts for blood-meals. Ciilex, spp., generally prefer avian hosts ^h\\t Anopheles, 



spp., feed on mammalian hosts (e.g. man) [5]. Therefore, there are some innate 



differences in the genetic make-up of different species. This difference will result 



in different preferences for various cues (attractants) as well as differences in sensilla 



between species. 



Mosquito sensilla 



Sensilla, or sense organs, are constituents of the PNS. The function of a 

 sensillum is to transform a response from a stimulus into a viable means of response 

 the mosquito can process, such as a nervous impulse [4]. There are a range of 

 sensilla which can function to detect variations of thermal, chemical, mechanical, or 

 visual stimuli, as well as changes in humidity. Visual detection will be addressed 

 under its own section separate from this discussion of other sensilla. 



There are five types of chemosensilla found on the antennae o{ Ae. aeg\'pti 

 and one type of chemosensillum on the palps (capitate pegs) [4,5]. The capitate pegs 

 function in the detection of carbon dioxide. Grooved pegs, found on the antennae 

 flagellar segments, respond to airborne vapors. These vapors may be water vapor 

 or other airborne volatiles such as lactic acid, fatty acids, and essential oils in the 

 case oiAe. aegypti [6]. The detection by grooved pegs and palps is processed by the 

 CNS (see pg. 8); i.e., detection by each of these sensilla is specific and independent 

 for different cues [7]. Anophelines contain large sensilla coeloconica which are 

 thought to be similar to grooved pegs. The detection purpose of these sensilla is still 



