Voyeur

I spend a happy hour in the garden yesterday afternoon observing the mating behaviour of the Conopidae (thick-headed flies), such are the passions of a Dipterist. The species in question was Sicus ferrigineus, a fly that we have been seeing in the garden over the last couple of weeks, favouring the scabious (Scabiosa) flowers.

The pairs of flies stayed latched together throughout. I assumed that the deed had already been done, and the male was ensuring that no other male could dislodge his sperm and mate with the female. The female was nectaring on flowers (she probably needed the energy), though her flight was not quite as agile as normal with the extra baggage.

Sicus ferrugineus

This was all very nice and romantic, but things were about to get a whole lot more interesting. There was another male taking close account of the goings on and he decided that he wanted to get involved with a bit of menage-a-trois action. He latched onto the back of the male, with the triple decker causing the female to become a bit more laboured. When trying to fly to another flower the group dropped like a stone, with the interfering male shaken off. He tried a couple more times, but did not manage to dislodge male number one.

Sicus ferrugineus