Insights into the biochemical basis of ovipositional preference of Earias vittella (Fabricius) in Abelmoschus species

The present study investigated the ovipositional preference of okra shoot and fruit borer, Earias vittella (Fabricius) (Order: Lepidoptera; Family: Noctuidae) in relation to host plant biochemical traits independently and also through combining with host plant morphological traits in different wild and cultivated Abelmoschus species. Correlation studies revealed a significant positive relationship between the number of eggs laid by E. vittella to total protein (P, r = 0.17) and a significant negative relationship with total phenols (TP, r = -0.57), total flavonoids (TF, r = -0.38), total sugar (TS, r = -0.57) and total reducing sugars (TRS, r = -0.64). Path co-efficient analysis revealed that total phenols, flavonoids, and total reducing sugars appear to be particularly important, as they, directly and indirectly, affect E. vittella egg-laying choice. Multiple step-wise regression analyses of the number of eggs laid by E. vittella on different Abelmoschus species with host plant biochemical traits together explained the variability in the egg laying to the tune of 54% (R² = 0.54; Y=26.71-0.30_TP+0.32_TF-1.39TS-4.41_TRS+8.29_P; R²=0.54; VIF=2.19). Further, combining the significant biochemical traits (TRS and P) with significant morphological traits (FL: fruit length, FW: fruit width, T: trichomes) based on r/SE explained the variability in the number of eggs laid by E. vittella to the tune of 78%; Y=7.15+1.35_FL-3.64_FW+0.05_T-2.00_TRS+1.66_P; R₂=0.78; VIF=4.56.