Butenolides in small ermine moths,Yponomeuta spp. (Lepidoptera: Yponomeutidae), and spindle-tree,Euonymus europaeus (Celastraceae).

A new butenolide, isosiphonodin [3-hydroxymethyl-2(5H)-furanone], along with a trace of siphonodin [4-hydroxymethyl-2(5H)-furanone], was isolated from fifth-instar larvae of the small ermine mothYponomeuta cagnagellus. Leaves of its host plant spindle-tree,Euonymus europaeus, were found to contain the same two butenolides with siphonodin being present as the major compound. TLC showed that isosiphonodin was also present in larvae or pupae of six other small ermine moths which did not feed on spindle-tree. InY. cagnagellus butenolides might be plant derived, while isosiphonodin in the other investigated small ermine moths is probably synthesized by the insect. The possible role of butenolides in the chemical defense of small ermine moths is discussed.