OLFACTORY RESPONSES OF AULACOPHORA FOVEICOLLIS LUCAS – AN ECOLOGICALLY IMPORTANT PEST - FROM WEST BENGAL, INDIA

Abstract

Pumpkin, Cucurbita maxima, is severely harmed by Aulacophora foveicollis Lucas (Coleoptera: Chrysomelidae), as a major insect pest of the plant. Based on Scanning electron microscopic analysis, compared to mechanosensilla, prevalence of antennal olfactory sensilla, was observed. The number of olfactory sensilla in the circumferential band of IXth antennal segment was higher in female species. Stimulation of the sensilla present on the antennae of A. foveicollis was analyzed by electroantennogram (EAG) at four different concentrations viz. 10.0, 5.0, 1.0, and 0.1 mg/ml in both sexes. The male species displayed greatest peak amplitude at 5mg/mL for heneicosane, whereas the female species displayed maximum peak amplitude at 10.0 mg/mL for 2-methyl phenol followed by 5.0 mg/mL for 1,4-dimethoxybenzene. However, pooled EAG data revealed that GLV elicited the strongest reactions, followed by aliphatic chemicals, oxygenated monoterpenes, hydrocarbon monoterpenes, and sesqueterpenes. These findings univocally shows that the pest's antennal responses clearly displayed sexual dimorphism.