Greenhouse Millipede - Oxidus gracilis

2 mysteries are solved here ( as of 07 -15 -10 ):

Questions:

1. What kind of millipedes are these?
2. Why do I often find then in swarms on top of each other?

Answers:

1. Greenhouse Millipede ( Oxidus gracilis )
2. As quoted by Aaron Goodwin from Bugguide:

A lot of times the male millipede will run over the top of the female to stimulate her with his legs. I've seen it with captive African giants and also desert millipedes (Orthoporus ornatus).

It's interesting to see them mosey along at a slow pace, and then all of a sudden a male will move really fast over the top of a female. Once he reaches her head, they turn face-to-face for copulation, or sperm transfer.

- Aaron Goodwin @Bugguide

Finally. I would see swarms of these on the fences at camp on damp mornings and lots of them would be on top of each other ( sometimes 3 at a time! Males fighting for dominance? ).

I'm immensely pleased to know the actual reason. I knew it had something to do with.....hem hem... sex but since millipedes don't mate on top of each other I naturally had questions. But I didn't know where to begin to search for answers.

So I'm finally happy to have some after years of wondering. I thought many things but all of them were wrong....in a sense. I was right about one thing.

It all had to do with.....*blush* sex. So there you go. XD

Hope Mr. Goodwin doesn't mind me quoting him. ^.^;