Longhorned beetles (Anoplophora nobilis) cause serious damage and loss on poplar, willow in north China. Planting mixed forest was thought a better measure to control them, replenish the loss of forest and gradually replace pure forest according to previous research. But how to afforest mixed forest is a mystery which need to be exposed. Hence, the selecting-host behavior of longhorned beetles should be studied as a basis for making a strategic decision. In 1994, the behavior of selecting host of longhorned beetles was observed in a mixed forest consisted of 30 species of trees. The results showed: for different species of trees, the longhorned beetles had different selecting-host behavior respectively. The susceptive host trees in mixed forest, such as acer oliverianum, could finally be selected by a complex, time-consuming and gradual sense behavior. After a few longhorned beetles fed, mated on them, it was sure that more longhorned beetles would be attracted to them, and finally the susceptive trees were damaged seriously. It was obvious that longhorned beetles were attracted by the odor of hosts firstly, then by intraspecific sex attraction. However, for some species of trees, such as platycladus orientalis and robinia pseudoacacia, longhorned beetles loved to approach to them, selected them and sometimes inhabited on them for a long time, but they didn’t feed on them and had no mating behavior. It was thought that the odor of host trees apparently influenced this behavior of longhorned beetles. So, mixed forest could only delay the time that longhorned beetles reached susceptive hosts, but it couldn’t effectively prevent their invasion. When afforested, many trees, like platycladus orientalis, should be planted and a few susceptive trees, like acer oliverianum or poplar, should be planted as trap trees in mixed forest. Generally, longhorned beetles probed which species of trees they liked by swinging antenna, rubbing tarsus besides vision before they reached them. Beetles’ compound eyes or visual sense was the most important sense organ, and the next is antenna and tarsus. If losing vision, longhorned beetles would not know where they should head for, often went around at one place, and lost their most flying ability. Labial palpi and maxillary palp functioned only when longhorned beetles probed which food was flavorful or delicious. Tarsus was useful and indispensable in the whole selecting-host procedure because, together with other sense organs, it often supplied information for longhorned beetles to affirm hosts.

Index terms: Anoplophora nobilis, behavior, selecting host, sense organs, forest.

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