Herbivorous insects use plant metabolites to inform their host plant selection for oviposition. These host-selection behaviors are often consistent with the preference-performance hypothesis; females oviposit on hosts that maximize the performance of their offspring. However, the metabolites used for these oviposition choices and those responsible for differences in offspring performance remain unknown for ecologically-relevant interactions. In this time, I will talk about the host-selection behaviors of two sympatric weevils, the Datura (Trichobaris compacta) and tobacco (T. mucorea) weevils in field- and glasshouse-experiments with transgenic host plants specifically altered indifferent components of their secondary metabolism. In addition, I will show that adult females are able to choose the best host plant for their offspring and use chemicals different from those that influence larval performance to inform their oviposition decisions.