Mating Brimstones

A few weeks ago, I was wondering why I had never seen mating Brimstones (Gonepteryx rhamni). This is a common and widespread species in England and I started to ponder as to how I might witness such an event.

By the time I started watching Brimstones in previous years, usually during April and May, any courtship behaviour by males was invariably rejected by the females.

It seemed likely that most females are mated early in the season, soon after they wake from hibernation and this year, I set out to keep a close eye on Brimstone activity.

February 15th was a warm and sunny spring-like day and in a sheltered corner of a local wood, it wasn't long before I was seeing my first Brimstones of the year. I saw at least 10 males rapidly quartering the rides and beds of dead bracken. Over the next few weeks I saw more males but no females.

 It became clear to me that females either remain hidden and wait to be found by a male, or they emerge from hibernation much later than the males.

I saw my first female Brimstone on 14th. March. She was flying slowly and erratically over the undergrowth and my plan was to follow her for as long as possible. However, within a minute, a passing male homed in on her and after a very brief courtship they were mating.

Brimstone (Gonepteryx rhamni) (mating)