Scanning electron morphological studies of Tribolium confusum Jacquelin du Val (Coleopteran: Tenebrionidae)

Abstract Background The confused flour beetle Tribolium confusum Jacquelin du Val (Coleopteran: Tenebrionidae) is the most destructive pest of stored products worldwide. It is the most common pest of wheat flour. Results This study describes and illustrates the larvae, pupae, and adults of T. confusum using scanning electron microscopy. The first larval instars are 5.0–5.1 mm long and 0.5–0.6 mm wide whereas the last larval instars are 5.75–6.9 mm long and 0.75–0.95 mm wide. Adults of T. confusum are reddish brown elongate beetles (4.0–4.5 mm in body length and 1.0–1.2 mm in width). Electron micrographs revealed the structure of the mouth parts during the larval, pupal, and adult stages as well as the structure of thoracic and abdominal appendages. Results indicated that the setiferous sex patches which were reported in males can often be used for sexing specimens. A specific feature of the first instar larvae of T. confusum is the extreme shortened antenna with a reduced number of antennomeres and the presence of well-developed and moderately long legs. Conclusion SEM examination may help us not only discover and understand new morphological details as the pits with spine on the elytra and the spikes on the membrane wings which will facilitate the identification of this species but also clarify the functions of various body parts.