**3.6.1.2.1 Sensilla chaetica** 1

The S. chaetica 1 on the lateral sides of the club more curved on the antennal shaft and increased in size. The two branches of sensilla arise from the base of sensilla and are equal in length. The sensilla measure about 37.5 µm in length and about 8 µm in diameter (Fig.5A). The S. chaetica1 on the surface of the club become curved as if it needs support from nearby ones (Fig.5D).

Fig. 5. SEM photomicrographs of irradiated adult antenna of *Rhynchophorus Ferrugineus* with 15 Gy of gamma rays. (A): Enflected sensilla chaetica1 (Ch1) on the lateral side of club,

Ultrastructure Alterations in the Red Palm Weevil Antennal Sensilla Induced By Gamma Irradiation 239

Fig. 6. SEM photomicrographs of irradiated adult antenna of *Rhynchophorus Ferrugineus* with 20 Gy of gamma rays. (A): Tall sensilla coeloconic1 (C1) on the scape, (B): Sensilla coeloconic 2 (C2) on the pedicel, (C): Sensilla basiconic 1 (B1) on the ventral side between scape and pedicel and (D): Sensilla coeloconic 3 (C3) on the funicel. [Scale bars indicate 50 µm (A), 10

The sensilla thinned out, some of them lost the bifurcation at the apical part others fade into a blunt tip (Fig.6C). The length of sensilla ranged from about 18.5 to 27 µm in length and

µm (B) and 20 µm (C, D), respectively]

**3.6.2.3 Sensilla basiconica 1** 

about 6 µm in diameter.

(B): Swollen sensilla chaetica 2 (Ch2) on the surface of the club, (C): Blunt swollen tip of sensilla chaetica 2 (Ch2), (D): Irregularity of sensilla chaetica1(Ch1) on the surface of the club. [Scale bars indicate 20 µm (A), 100 µm (B) and 10 µm (C, D), respectively]

### **3.6.1.2.2 Sensilla chaetica 2**

The sensilla became shorter, swollen near to the base. The apical part of the sensilla is suddenly interrupted into a blunt swollen tip (Fig. 5C).

#### **3.6.1.3 Sensilla basiconica 1**

The sensilla fewer in number and thickened out, shrunken and thinner near to the tip; the bifurcated end appears located more towards the apex. The length measures from about 6.5 to10 µm and the diameter about 2 µm (Fig.4C).
