Culex pipiens mosquito is considered as one of the most dangerous insect pests that affect humans and animals worldwide as they transmit epidemic and fatal diseases. Antennal structure of the normal and irradiated female mosquito, Culex pipiens was examined using scanning electron microscopy to study the changes in the antennal segments and associated sensilla when 1e2 days old pupae were irradiated at low dose (20Gy), moderate (40Gy) and high (80Gy). The antenna of the female C. pipiens is filamentous in shape and consisted of scape (S), pedicel (P) and flagellum (F) which has 13 flagellomeres. Various types of sensilla with distinct morphological characters and morphometric features were recorded. Sensilla trichodea are the most abundant sensilla observed, with other types like sensilla chaetica, sensilla basiconica (grooved peg), sensilla coeloconica and sensilla ampullaceal. Morphological changes were recorded to the antennal segments and their associated sensilla due to the doses of gamma radiation (20, 40 and 80Gy) such as shrinkage, curved of sensilla into different directions, irregularity in shape, swollen in some parts and some sensilla gathered into dense collections. These changes were obviously demonstrated at 80Gy and 40Gy doses whereas little malformations were observed when the pupae irradiated with 20Gy dose. The antenna has lost most of different types of sensilla and some of its segments became transparent with high and moderate doses. These changes also recorded in the distal 13th flagellomeres segments with the three used doses of gamma radiation compared to control ones.

Films of high-density polyethylene (HDPE) incorporated with different nanoparticles, ZnO or Ag, were prepared to protect food products from the stored-product insect pests. The developed composites were irradiated at different radiation doses and the associated properties were investigated in terms of gel content percent, tensile mechanical properties, thermal properties, and morphology. The possible application of the irradiated products in food industry via the insect pest test was investigated. The gel content percentage of the irradiated HDPE films loaded with ZnO and Ag nanoparticles demonstrated higher values than those of unirradiated unloaded films and unirradiated loaded HDPE. The mechanical measurements indicated significant increments by loading with nanoparticles as well as by irradiation. The tensile strength raised up to about 177 and 158% by adding 2% ZnO and Ag, respectively. Conversely, the elongation percentage was decreased by increasing nanoparticle concentration and by radiation dose. Thermogravimetric analysis elaborated that the thermal stability of the nanocomposites was lesser than that of HDPE unloaded films, yet improved by irradiation. The insect pest test revealed that the adults of Sitophilus granarius could not penetrate the loaded and irradiated HDPE film. The most efficient formulation was reported for the HDPE films incorporated with 2% Ag irradiated with a dose of 75 kGy. J. VINYL ADDIT.TECHNOL., 25:E120-E129, 2019.

The effect of different dose levels of gamma irradiation on the morphology and distribution of the sensory receptors of the antennae of lesser grain borer, Rhyzopertha dominica (F.), was studied with the scanning electron microscope. The results obtained distinguished three types of sensilla: chaetica (ch1"long" and ch2 "short"), basiconica (b), and ampucellaceous (am) present on the apical distal three segments of flagellomeres. Irradiation with a dose level of 75 Gy had no effect on the general distribution of different types of sensilla as compared with the control, whereas dose levels of 100, 150, and 200 Gy showed malformation which increased with the increased doses.

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.

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To investigate the effect of Gamma radiation on the reproductive systems of emerged female and male of Ephestia cautella (Walker) moths, mature pupae of both sexes were irradiated with doses of 50, 100 and 150 Gy. Histological study of the treated individuals showed in females that the ovaries appear sever damage in the follicular epithelium at all doses, which become thinness and separated from developing oocytes, moreover, some of the nurse cells were rupture. In males which treated with 150 Gy, it was noticed retardation in the stages of spermatogenesis and few numbers of sperm bundles and their dispersion in the testicular follicles’ adults, on the other hand, the doses of 50 and 100 Gy showed little or moderate effects on the structure of the testis contents.

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