Importance of Plant Physical Cues in Host Acceptance for Oviposition by Busseola Fusca

Plant and surrogate stems exhibiting specific combinations of physical cues were used to determine which plant-related stimuli influence the oviposition of Busseola fusca (Fuller) (Lepidoptera: Noctuidae). The number of eggs and egg batches laid per female increased with an increase in diameter of both natural and artificial stems. Direct observations of the oviposition behaviour (walking, antennating, and sweeping with the ovipositor) indicated that the female moths preferred oviposition supports with a large diameter and non-pubescent or smooth surfaces over pubescent or rough ones. Pubescence and rough surfaces significantly affected the behavioural steps leading to oviposition by interfering with the ovipositor sweep process necessary to find a suitable oviposition site. Furthermore, more eggs and egg batches were laid on soft than rigid supports. The rigidity of the support affected the proper insertion of the ovipositor for egg deposition. Our results underline the importance of physical stimuli in B. fusca ’s choice of an oviposition site, which may facilitate the identification of potential host plants or preferred oviposition sites on a plant for this species.