The Visual Cues In The Host Location And Visual Preference By Ambrostoma Quadriimpressum

The highly specialized chrysomelid Ambrostoma quadriimpressum Motschulsky (Coleoptera: Chrysomelidae) is strictly monophagous on elm trees, Ulmus pumila (Ulmaceae). This study had researched the lost location mechanism of the beetle and their relevant visual ability. The following are the results:1. In no-choice experiments under semi-natural conditions, beetles were released in distance of 1.5m from the host. Three treatments were tested, in which they were facing towards the host, away from the host but facing towards a black paper column, away from the host with no standing target in view. Video-recordings of the beetles’ walking tracks showed that a standing visual target in field of vision strongly influenced their behavior. The host plant and black paper column equally attracted beetles facing released towards them.2. In choice experiments under semi-natural conditions, the beetles randomly moved to both host and non-host plants, as well as to the host-plant and the black paper column, indicating that they do not discriminate host plants from a distance. This result shows the importance of visual cues on host location.3. The interest in black targets of beetles in the laboratory showed that higher, wider, vertical, and solid black targets are more attractive to the beetle than targets that are shorter, thinner, inclined or have stripes, whereas the details of the edge of the vertical target (wavy or serrated) do not affect attraction. In the field during the search for a host, these visual preferences could help the beetle avoid stones, herbs or shrubs, and target tall trees that have an obvious trunk.4.Under lighting condition in the laboratory, Red targets were significantly more attractive than the yellow, blue and green targets to beetles. However there was no significant difference between the red targets and black targets on the beetle’s attraction.5. Under indoor dark condition, the beetles showed obvious photo-taxis to red and yellow light. Although the green object and light do not stimulate the orientation behavior of the beetle, green light attracted more beetles stay in the aperture than other single color lights. This result showed that green light has the effect of the retention behavior of the beetle.