Extreme intraspecific variation in Hystrichophora (Lepidoptera: Tortricidae) genitalia — questioning the lock-and-key hypothesis

The lock-and-key hypothesis of genital evolution is evaluated using the highly variable male genitalia of two species of Hystrichophora (Tortricidae: Olethreutinae) moths. Traditionally, morphological differences in male genitalia have been used to differentiate similar species of Lepidoptera, and, while other characters may be examined, it is often assumed that genital morphology is the unique characteristic that "defines" a species. The significance of this assumption is based, many times unknowingly, on the lock-and-key hypothesis, which states that male and female genital compatibility serves to isolate different species reproductively. This concept is tested by quantifying the shape of Hystrichophora male valvae and analyzing variation in individual populations using principal components analysis. The resulting extreme levels of intraspecific variation support evolution by means of sexual selection and reject the traditional lock-and-key hypothesis.