Olfactory response of the lady beetle Hippodamia convergens (Coleoptera : Coccinellidae) to prey related odors, including a scanning electron microscopy study of the antennal sensilla

The olfactory ability of the convergent lady beetle, Hippodamia convergens Guerin-Meneville, was investigated using an 8-arm airflow olfactometer. Lad y beetles tested were normal or had their antennal tips, or maxillary palps amputated. Normal beetles and those with their maxillary palps removed wer e highly attracted by the odor of radish leaves infested with green peach a phids, Myzus persicae (Sulzer). Beetles with their antennae or antennal tip s removed were not attracted. In addition. the normal lady beetles were sig nificantly attracted to clean radish leaves. These results indicate that H. convergens can perceive olfactory stimuli released their prey and their pr ey's host plant (or a combination of the two) and that the beetles' olfacto ry receptors are located principally on the tips of their antennae. Also as part of this study, the antennal sensilla of male and female convergent la dy beetles were examined using scanning electron microscopy. The sensilla w ere counted the majority of which were located on the terminal segment, and 4 morphological classes were identified: chetiform, Bohm, basiconic, and t richoid. Chetiform sensilla were observed on all 11 antennal segments, whil e the Bohm sensilla were located only on the first two segments. The basico nic and trichoid sensilla were located exclusively on the terminal two segm ents. The most abundant sensilla on the terminal segment, trichoid sensilla , were suggested to function in olfaction.