For native herbivores, novel plant communities formed by the introduction of nonnative species represent both more complex and less reliable resource environments. In many cases native herbivores recognize a nonnative plant as a resource despite not being able to successfully exploit it. Butterflies are particularly susceptible to maladaptive use of novel plants since most of them have very specialized diets, feeding on plants from no more than three families. In many cases, butterflies and other insects first interact with a novel host through the egg-laying decisions of females, making oviposition preference an important phenotype for exploring how the structure of heritable genetic variation affects adaptive responses to novel hosts. Previous research detected a sex-linked genetic basis for oviposition preference differences between species of butterflies and between geographically distant populations. On the other hand, studies within butterfly and moth populations have found that detectable variation in oviposition preference tends to exhibit autosomal inheritance. However, no one has examined whether this inheritance pattern persists within populations whose stable historical resource environment has been disturbed by novel host plants. In their latest study titled "Novel host unmasks heritable variation in plant preference within an insect population", former graduate student Dr. Rachel Steward, Rebecca S. Epanchin-Niell and their mentor Dr. Carol Boggs quantified the heritability of preference for the invasive Eurasian mustard Thlaspi arvense within a population of Pieris macdunnoughii butterflies, which are found in regions of Montana, Wyoming, and Colorado. Unexpectedly, they found evidence for within-population sex-linked, rather than autosomal, genetic variation in preference for T. arvense over native hosts, indicating that persistent maladaptive oviposition on this lethal plant must be maintained by alternative evolutionary dynamics such as migration- or drift-selection balance or pleiotropic constraints. Congrats!