Abstract
A field study on the status of forest trees infested with Endoclita sinensis (Lepidoptera: Hepialidae)
was conducted in a natural forest around Renyi Lake in Chiayi County, southwestern Taiwan.
Host plants of E. sinensis included Macaranga tanarius and Mallotus paniculatus in the family
Euphorbiaceae, as these plants showed the highest infestation rates. Endoclita sinensis larvae
bored into the trunks of 6~24 cm diameter and 10~200 cm high and fed on callus tissue around the
hole, which was covered with silk, debris, and feces. Normally, only 1 larva was found per tree;
however, when the trunk diameter was larger than 10 cm, more than 2 well-separated larvae could
be found. In the forest, larvae dispersed in a cluster or in a clumped pattern. Female larvae were
significantly larger than male larvae in body length and weight, head capsule width, and pupal
length and weight. Field-collected E. sinensis larvae exhibited a male to female ratio of 1: 1.2 after
being fed an artificial diet.