Purple emperor and Lesser purple emperor butterflies – a simplified life cycle and how to see them.
These two butterflies spend most of their time in the woodland canopy where they feed on aphid honeydew, or occasionally when they descend to feed on sap runs or, in the case of the male, animal droppings, carrion or moist ground that provide much needed salts and minerals which are generally the only times we get the chance to see them.
Click on images to expand
Above - Male
Above - Female
Both species use willows, principally Goat willow, and in the case of the Lesser Purple Emperor poplars as well, especially Populus tremula, for their caterpillars to feed on.
Eggs are placed singly on leaves near the tree canopy and the caterpillars have an extraordinary life cycle that can last 300 days or more with various pauses between each instar change, the last before pupation being a long hibernation through winter in a crevice or branch fork wrapped in a little spun silk. Pupation takes place in spring and adults fly from May.
Both species can be observed throughout
France where there are woodlands or copses
but are more numerous in the warmer parts of the country.
As mentioned above they are drawn to animal droppings, carrion or moist ground where they can access minerals and other salts and many people make up mixtures to attract them during the summer months. Most of these mixtures are fairly foul by human standards and frequently contain rotting shrimp and other seafood or fish such as sardine. Best put in a container for a week or two somewhere warm before being put out on the ground on a sunny morning in July or August. Dead animals and mammal excrement are also popular but maybe not something everyone would want in their garden.
Of course your success will be dependant on the butterflies being present which is one more good reason for growing Goat willow and even if you don’t have either species of Purple Emperor where you are these mixes will attract some other species of butterfly.
Have fun - Chris