Fennel Butterfly

Exhibit of the Month 5 / 2023

The fennel butterfly is one of our most well-known butterflies. It is depicted on many book covers and is often associated with nature conservation, as it is one of the specially protected species, although it is not currently completely endangered.

The fennel butterfly is a striking butterfly with a wingspan of up to around 10 centimeters. It occurs from Europe to Japan. In our country, it is currently widespread throughout the territory, but this has not always been the case. In the 1970s and 1980s, it experienced a significant decline in population and became rare. At that time, it was primarily found in larger steppe areas or, for example, in wetland areas in the foothills. Today, it occurs in non-forested habitats, especially in agricultural landscapes, as well as in cultural meadows, gardens, steppes, and even forest steppes. We also find it in spoil heaps or reclaimed areas of surface mines. The caterpillars of the fennel butterfly feed on various plant species. Most commonly, these are common carrot, fragrant dill, forest angelica, or various species of masterwort.

This species has two, and exceptionally three, generations per year. We can encounter it from April to October. Interestingly, males and females meet at elevated places (e.g., hilltops). This behavior is called hilltoping. If you want to observe this species, just visit the hills around Most in May. It is abundant, for example, on Písečný vrch near Bečov, or you can encounter it in the summit area of Zlatník Hill or on Bořní.

Text and photo: Pavel Krásenský - entomologist OMGM