HOST ANT TRAIL FOLLOWING BY MYRMECOPHILOUS LARVAE OF LIPHYRINAE (LEPIDOPTERA, LYCAENIDAE)

In this study we report a case of ant-trail following by lycaenid cate rpillars. Euliphyra mirifica and E. leucyana caterpillars are involved in a commensal association with the weaver ant Oecophylla longinoda. The host nests are made with leaves which over the course of time dry out or are broken open by storms, forcing the ants to migrate and buil d a new nest elsewhere. Euliphyra caterpillars are stimulated by recru itment behaviour which triggers the migration of their host. They then follow the host trails leading to the new nesting site. Laboratory ex periments showed that these caterpillars are able to follow host trail s under varied conditions: (1) fresh trails actually used by workers, (2) fresh trails in the absence of workers, (3) heterocolonial, 2-mont h-old trails, and (4) fresh trails washed with water (to simulate the effect of tropical rains). They can also bridge trail gaps of more tha n 1 cm. Under natural conditions, the trails are frequently situated a long thin twigs. The forward progress of the ants in such a situation is not impeded by the presence of large Euliphyra larvae. Workers just climb over the caterpillars, even on larger trails where there is eno ugh room to pass alongside them. This suggests that an allomone is sec reted on the dorsal part of the caterpillars. When crawling along hete rocolonial trails, the caterpillars are not attacked, even if about 21 % of the workers from the new colony spread their mandibles when encou ntering them. They are then adopted and are admitted to the nest of th e new host colony of O. longinoda.