Impact of UV-C radiation on morphology of the antenna and antennal sensilla in Tribolium castaneum (Coleoptera: Tenebrionidae)

Abstract

The present study reveals the effects of ultraviolet-C on the morphology of the antenna and antennal sensilla of Tribolium castaneum. Pupae were irradiated with UV-C at a distance of 35 cm for 1, 2, 4, 8, 16, 32, or 64 min. The morphometric traits of the antenna and antennal sensilla were determined using light and scanning electron microscopy. UV-C caused abnormalities to the adults' antennae that were classified into 3 levels; mildly, moderately and strongly affected. A loss of segmentation occurred in the funicle and club, and the antennae were greatly reduced in size overall. The severity of the antennal abnormalities occurred in a dosedependent manner. The UV-C radiation significantly decreased the length of the scape, funicle, and club and the width of the club. Scanning electron microscopy of the resulting adults showed the antennae had a wrinkled cuticle, and the sensilla were fewer in number. The long sensilla trichodea became shorter, while the long and short sensilla trichodea were broader. Likewise, the width of sensilla basiconica subtypes 1 and 2 also increased after the UV-C irradiation. The results indicate that UV-C irradiation causes specific malformations in the antennae and antennal sensilla of T. castaneum.