Females prefer to lay eggs on leaves with the highest chlorophyll contents. Therefore, the reflectance and chlorophyll concentration of leaves also affects the choice of oviposition site for "E. aurinia". Chlorophyll content (the "greenness" of plants) can be an indicator for increased fitness of the host plant, which in turn will provide optimal growth opportunities for the newly hatched larvae. Females therefore use visual cues to seek out the greenest leaves to lay their eggs on. However, there are also indications that it is not high chlorophyll concentration but the presence of conspecific egg clusters which attracts females to oviposit on a certain leaf.