Ragweed Borer (Lepidoptera: Tortricidae: Eucosmini): Taxonomic Implications of an Allometric Analysis of Adult Characters

Abstract

Epiblema strenuana (Walker) and E. minutana (Kearfott), which develop on ragweed (Ambrosia spp.) and other plants, have been differentiated by previous authors on the basis of forewing length-width ratio, male valval neck width, male socius length, female signa base diameter, and female sterigma length-width ratio. These variables (y) were examined relative to forewing length (L), a surrogate for insect size, using the nonlinear form of the allometric equation, y = b(L^k). Study material consisted of 101 adults corresponding to both species originating in 17 states. All variables were significantly affected by insect size, with values of k ranging from −0.25 to 2.32. No discontinuities suggesting multiple species or interspecies limits were found in any relation. Allometric analysis could prove useful in studying problems of this type in other Lepidoptera. Lectotypes of E. strenuana and E. exvagana (Walker) are also designated.