Piercing and sucking mouth parts sensilla of irradiated mosquito, Culex pipiens (Diptera: Culicidae) with gamma radiation

Abstract

Morphology, distribution and function of the sensilla associated with mouthparts of female mosquito, Culex pipiens (Diptera: Culicidae) were studied by using the scanning electron microscope. The female mosquito mouthpart is a piercing and sucking type and carrying many sensory organs which plays major role in host seeking, and oviposition behaviour of mosquitoes. Six types of mouthpart sensilla have been identified and described, Sensilla trichoidea, chaetica, basiconica, Capitate peg, campaniformia and squamiformia. Females mosquito were irradiated as pupae with 20, 40 and 80 Gy of gamma radiation to investigate their effect on mouthparts sensilla. Dose of 20 Gy had slight effect on the different types of the sensilla as compared with the control. Features of malformation observed in the maxillary palp segments at this radiation dose include falling of some scales (sensilla squamiformia) at certain parts of the 1st segment leaving vacuoles. At 40 Gy, the maxillary palp segments were liquefied in some areas leaving undistinguished shape. At the highest dose 80 Gy, the tip of labial palps had many tears and showed were most affected, especially, at the trichoid, basiconic and chateica sensilla. All these malformations may lead the mosquitoes to not reaching the host, impeding their ability to transmit diseases or killing the mosquitoes, and this is the main objective of this study.