Abstract
Suitability of various ornamental trees as a host plant of the fleabeetle, Argopistes coccinelliformis CSIKI was investigated. Results of the field observations and some laboratory tests showed that adult beetles preferred Osmanthus×Fortunei, O. heterophillus, O. fragrans, O. f. var. aurantiacus, Ligustrum japonicum, L. ovalifolium, L. obutusifolium, Syringa vulgalis and S. reticurata as hosts for feeding and oviposition, and that they did not show much interest in Jusminum, Forsythia, Fraxinus plants nor Ligustrum licidum. Developmental succcess of immature stages were observed under the field conditions, and the results showed that Osmanthus×Fortunei, O. heterophillus and Ligustrum japonicum were suitable hosts. These results suggest some differences between the host plant preferences of larvae and adults of this beetle. Adult beetles left conspicuous feeding traces on the leaf, contrasting with a series of short feeding marks. However, little correlation was detected between the length of each feeding mark and the total feeding activity of the beetle on various host species. Furthermore, it was suggested that data on feeding amount and number of eggs deposited by adults alone might not provide a sound picture of host preference of this beetle. Based on the overall results observed, Osmanthus×Fortunei seems to be the most suitable host species of this beetle among the various trees investigated.
