First, tackle the difference in the levels. Much of the research I've seen is basically saying that it's easier for women to stay close to home, and that's partly because they have responsibilities, and responsibilities that they can't rely on their partners to take care of to the same degree men can. There is this notion that they need to be home, if you will, or at least as close as possible to home. Travelling to Ottawa is quite a burden, depending on where you are in the country, and I think that's part of it.
There's also a belief that Ottawa is higher, harder and more important. Again, when we think of political ambition, we know that women tend to downplay their skills. Therefore, even if you have the notion that you might want to participate in politics and that you might want to run.... By the way, we're talking about 1% of women and 5% of men, so it's a very small, and yet large, number of individuals. If you have the sense that you may want to run, you're likely—and I have to admit I've done this—to say well if I'm going to do it, maybe I should do it at the civic level because that's a bit easier; it's not likely to be quite as difficult. You start low, in a way, and it's part of women's political ambition.
The second part of your question was about why they vote but do not run at the same levels. You heard from Melanee Thomas, my colleague at the University of Calgary. She's done a lot of work on the notion of stereotypes and so on, and her early work in her Ph.D. was on political interest and political engagement among women. Part of it is that voting is not as difficult a political act as running for office—those are two very different things. We tend to say it's all about political engagement, but they're not the same; they're very different.