Endangered on our doorstep

False Bay Unique Ranger
Kedestes lenis lenis

The False Bay Unique Ranger (Kedestes lenis lenis) is a small butterfly endemic to the Western Cape.  They are “dull” looking butterflies (I know, I know, you were hoping for something pretty and colourful…) but they should not be overlooked because, despite looking like a moth, they are endangered.

False Bay Unique Ranger (Kedestes lenis lenis)

If you are lucky enough to spot them during their peak flight season in Spring (November), the male’s wingspan is 26 – 31mm and the female, 29 – 35mm.

According to the Red List of butterflies, they have very restricted habitat requirements and are only found at five localities on the Cape Flats.  Though previously widespread and common, most of its habitat on the Cape Flats north of Table Mountain has been destroyed (Claassens, 2000).  

Distribution map

Of the five localities mentioned above, the Cape Flats Nature Reserve has the largest stand of Imperata cylindrica (larval food plant) (so one would assume this reserve is full of Kedestes lenis lenis, right?) Unfortunately not…it is unknown why the population is so small and only restricted to two localities within the reserve, irrespective that the entire reserve is covered in their larval food plant.  Some of the other localities are restricted to a patch alongside a road, yet they yield more individual butterflies…the reason for this is unknown (research possibility).

Larval food plant (Imperata cylindrica)

Lepidopterists (butterfly specialists), Andrew Morton and Fanie Rautenbach do an annual survey for this butterfly at the CFNR but only a maximum of five individuals were recorded per survey.  What could the reason be for this small population?  Why are their numbers not increasing with a reserve full of their larval food plant?  The Imperata cylindrica growing in the reserve is quite old…do they perhaps prefer younger grass? There is no mention of an adult food plant in my search…what does the adult feed on?

There are so many questions about this butterfly and so little answers.  Research on this endangered butterfly is definitely needed to ensure its future.