This sequence was taken over a 15 minute period on 25 July 2009. It shows a pair of leopard slugs (Limax maximus) in the act of mating. The slugs are 'hermaphroditic', that is they carry both male and female organs. It still, however, takes a pair to breed.

When they are ready to mate, the slugs suspend themselves in mid-air by a length of mucus, and then entwine their bodies tightly together. The male organ then everts (emerges) from just behind the head of each slug, and together embark on a prehensile dance. The shots here show most of the stages as they twist together and create a blue-white, semi translucent globe. Both slugs are fertilized by the process, and then disentangle before going their separate way.

There's a BBC video (narrated by David Attenborough) over on YouTube. Or direct link to the BBC (needs Real Player).

The shots were taken hand-held on a Canon EOS 40D with the Sigma 105mm F2.8 EX DG macro lens and a standard Canon 430EX flash unit set to manual and 1/4 output. I also used the diffuser to control the light.