Variation in the female Frenulum in Tortricidae (Lepidoptera). Part 2. Olethreutinae

Authors: ROTA, JADRANKA - Smithsonian Institute; YANG, APRIL - University Of California; Brown, John

Submitted to: Proceedings of the Entomological Society of Washington
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/15/2009
Publication Date: 10/30/2009
Citation: Rota, J., Yang, A., Brown, J.W. 2009. Variation in the female Frenulum in Tortricidae (Lepidoptera). Part 2. Olethreutinae. Proceedings of the Entomological Society of Washington. 111:826-866.

Interpretive Summary: The larvae of moths of the family known as leaf-rollers are important pests of agricultural, ornamental, and forest plants, causing millions of dollars in damage each year. Understanding relationships among groups of these moths provides us with the predictive power to anticipate which groups may become pests, which may show promise for biological control, and which may have the potential to become invasive species. This is the second paper of a proposed three-part series in which we examine the occurrence of an anatomical character, the spines that allow the wings to function in unison. Knowledge of the variation in this character helps us define some groups of leaf-roller moths and provides us with clues about their relationships. This information will be of interest primarily to scientists involved in understanding relationships among groups of leaf-roller moths, but also to those interested in the evolution of, and variation in, the anatomical character we investigated, which occurs in many families of moths.

Technical Abstract: This paper, treating the tortricid subfamily Olethreutinae, represents the second in a proposed three-part series examining variation in the number of bristles in the frenulum of female tortricid moths. Based on an examination of 6,334 individuals of 1,466 species representing 188 genera of Olethreutinae, the number of bristles in the female frenulum varies from one to six, and it is sometimes asymmetrical on the same specimen (7.5% of individuals examined). A three-bristled frenulum is the most common state in Microcorsini, Endotheniini, Bactrini, Gatesclarkeanini, Olethreutini, Enarmoniini, and Eucosmini, with varying degrees of intraspecific variation in number within each tribe. However, in both Eucosmini and Enarmoniini several genera have a predominantly or exclusively two-bristled frenulum (e.g., Gypsonoma Meyrick, Herpystis Meyrick, and Rhopalovalva Kuznetsov in Eucosmini; Hystrichophora Walsingham, Neoanathamna Kawabe, and Pseudacroclita Oku in Enarmoniini). In Grapholitini, the two- and three-bristled frenulum occurs in nearly equal frequency, suggesting that these character states may be of some phylogenetic significance, but an overall pattern is not immediately obvious. In contrast to the situation in Chlidanotinae, where the distribution of the two- and three-bristled frenulum corroborates previously proposed phylogenetic hypotheses, we conclude that variation in the number of bristles in the frenulum in Olethreutinae is not phylogenetically informative at higher levels (e.g., tribes, subtribes) owing to the high degree of intrageneric and intraspecific variation. However, the number of bristles may be of some phylogenetic significance at the generic level, particularly in Eucosmini and Grapholitini.