Feeding Behavior of Collaria scenica (Stål) (Hemiptera: Miridae) on Wheat Plants: an EPG Waveform Characterization

In this study, we use for the first time the electropenetrography (EPG) technique to characterize and describe the feeding activities of Collaria scenica (Stål) adults and their respective waveforms on wheat, Triticum aestivum L. plants. It comprised of four waveforms, two related to non-feeding (Np and R) and two with feeding activities (CR and I). The Np wave represents the insect resting or walking on the plant surface (75% of the recording time). R wave was associated to sensory evaluation of leaf surface with the tip of the labium (labial dabbing activity-ca. 1% of the recording time). Feeding activities were of relative short duration; cell rupture waveform (CR-ca. 49 min-ca. 15% of the recording time) was highly irregular due to constant movement of the stylets internally in the plant tissue. The waveform I (ca. 28 min-ca. 9% of the recording time) showed stereotypical and repetitive pattern and represents ingestion of the cell contents previously degraded via cell-rupturing activities. The damage caused by C. scenica in wheat leaflets is a result of cell-rupturing activities, generated by action of digestive enzymes plus mechanical action of serrated mandibular stylets. This results in whitish streaks, dots, or spots on the leaflet of wheat plants which cause significant damage and eventually plants' death.