Oviposition Experiments Three experiments were carried out to study the oviposition behavior of M. cinxia in response to concentrations of iridoid glycosides and plant size of P. lanceolata. In experiments 1 and 2, we offered potted plants to butterflies in cages by using dual (exp. 1) or multiple (exp. 2) choice tests. In experiment 3, we transplanted plants and butterflies to a natural field plot. Experiments were carried out in Finland, except for one of the cage experiments (exp. 2) that was carried out in the Netherlands. In the cage experiments, none of the plants flowered, and M. cinxia females usually laid a single egg batch per plant