**3. Results**

The antenna of the red palm weevil measures about 0.9 cm in length (geniculate antenna). It arises from the elongated anta cava in front of the anterior margin of the compound eye and at the base of the rostrum. It consists of three segments, (scape, pedicel, and flagellum) differing in size and shape (Fig.1).

### **3.1 The scape**

230 Gamma Radiation

Despite the importance of sense organs on the antennae of red palm weevil (for oviposition, feeding and mating) there is little information about it. Therefore, the objective of current study is to describe the distribution, types of sensillae in *Rhynchophorus ferrugineus* using scanning electron microscopy, and estimate the effects of gamma radiation on them. This

Red palm weevil*, R. ferruginous* adults were obtained from cocoons collected from infested date palm trees in the Salhia district (Sharkiya governorate, Egypt). A large number of cocoons were put into oblong opaque –white plastic boxes ( 21 x10.5x 7 cm in length, width and high respectively) covered with tight-fitting and perforated lids. Cocoons were kept in wet toweling until adult emergence.The newly emerged adults were sexually differentiated. Newly laid eggs from the adult culture were collected using a 0.2 mm brush and inserted into round plastic Petri dishes (50 mm diameter x 20 mm high) containing tissue paper soaket in Benzoate solution, which was renewed daily. The Petri dish had a screw cap and uniformly spaced perforations (2 mm diameter) around the surface of the box including lid

The hatched larvae were maintained in plastic cups (250 ml capacity) containing 5g of artificial diet as described by Rahalkar *et al.,* (1985). The plastic cups were covered with muslin cloth and kept at controlled laboratory conditions (27°C and 85% RH). Daily inspection was carried out until eggs hatched and the larval and pupal stages were completed. After emergence, adult weevils were transferred into wire screen cages

Adults weevils, 2 weeks after emergence, irradiated with 15, 20 Gy of gamma radiation using gamma cell (60 Cobalt –Source), installed in the Middle Eastern Regional Radioisotope

unirradiated and the irradiated adult weevils were freeze by liquid nitrogen then dried in the chamber of the scanning electron –microscope, SEM (Jeol-JSM-5600 LV in SEM Unit, Central Laboratory for Elemental Analysis, Inshas, Egypt) in the low vacuum mode. Then the micrographs were taken, this technique called low vacuum scanning electron microscope freeze drying (L V-SEM)(Gasser *et al*.,2008) .This technique resulted in the presence of few small particles in white color represents ice during freeze drying technique

The antenna of the red palm weevil measures about 0.9 cm in length (geniculate antenna). It arises from the elongated anta cava in front of the anterior margin of the compound eye and

Center for the Arab Countries, Cairo, Egypt, with the dose rate of 1 Gy / 1.95 sec.

**2.3 Examination with the scanning electron microscope (SEM)** 

of the specimens in low vacuum SEM on the micrographs

information may be useful for controlling the pests.

**2. Materials and methods 2.1 Insect rearing technique** 

containing pieces of suger cane as food.

**2.2 Irradiated treatments** 

and bottom.

**3. Results** 

It is the longest segment; it measures more than one-third of the length of the antenna. Proximally, it has a hook fitting in the antennal groove, while distally it is somewhat thickened (Fig.1).
