Technical Note

Scanning electron microscopic studies on the head appendages and its sensory structures of an immature stage of Spilarctia obliqua (Wlk.) (Lepidoptera Arctiidae) – a pest of mulberry (Morus sp.).


Abstract


The mouthparts and antennae of the second and third instar larvae of Spilosoma obliqua Wlk., were studied using scanning electron microscope. The three segmented antenna bears sensory structures which are olfactory in function. The labrum and mandibles are also parts of the mouthparts and have their own function in selection and intake of food. Eight apical sensilla known to be olfactory are observed on the distal end of the maxillary palpus. The gustatory structures i.e., two sensory structures (ALP1 and ALP2), a fine sensory projection (STC), two sensory setae (SL1 and SL2) are observed on the maxillary palpi. A single pair of labial palpi, considered to be mechanoreceptors, is also observed. Further, the functional morphology of the sensory receptors on the head capsule of other lepidopterous larvae have also been discussed.  


Keywords

Sensory receptors; head appendages; S. obliqua; mulberry; ultastructure

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