Scanning electron microscopy study of the antennal sensilla of cob borer, Stenachroia elongella (Lepidoptera: Pyralidae)

Abstract

Stenachroia elongella is an important pest of maize in Meghalaya, India. To understand the roles of sensory organs in the biological behaviors of this insect, we determined the structure and distribution of sensilla found on the antenna of both male and female S. elongella by scanning electron microscope. The antenna of both sexes is a filiform type, and the overall length of the female antenna is significantly longer than the male antenna. In both sexes, seven types and two subtypes of antennal sensilla are identified; sensilla trichodea, sensilla chaetica, sensilla styloconica, sensilla coeloconica, sensilla auricillica (I, II), sensilla squamiformia and Böhm sensilla. No sexual dimorphism on the specific occurrence of sensilla is observed. Probable functions are discussed based on their external morphology. These results would be helpful for further studies on TEM investigations, electrophysiological recordings, and behavioral studies. Research Highlights Seven types and two subtypes of antennal sensilla were observed in both male and female Stenachroia elongella. Morphology and distribution of the antennal sensilla were discussed. Sexual dimorphism was observed on the overall length of the antenna where the female antenna is longer than the male antenna. No sexual dimorphism was observed on specific occurrences of antennal sensilla.

Morphological Characterization of the Antenna and Scent Patch of Three Danaus Species (Papilionoidea: Nymphalidae, Danainae)

“…The sensilla's morphological characteristics, including surface decorations that indicate their function, are similar to previous reports for D. gilippus and many other Lepidopteran species, except for STs. In Danaus and some butterfly species, such as Ascia monuste (Linnaeus) of Pieridae, the great southern white butterfly, it is smooth, but in Talponia batesi Heinrich of Tortricidae and Stenachroia elongella Hampson of Pyralidae, the cob borer, it has thread-like ridges [25,26]. Surface roughness has been speculated to be essential for detecting external volatiles [27].…”