I knew it was a redback spider when I found it on our sliding door at home, but a few other people commented on its interesting stripey markings.
So I did a little research and this is what I discovered:
"...Juvenile spiders have a more elaborate pattern including lateral stripes - this type of pattern is occasionally retained in adult females. Redback spiderlings are coloured white and black, but with each moult the black pigmentation increases and the red stripe gradually gets larger. The tiny males mature quickly and retain the early juvenile colour pattern. They are only about 3 mm in body length and are not dangerous. Female are up to12 mm body length.." [
source]
Considering this spider is the length of my thumbnail, chances are it's a female who has retained her juvenile markings. :)
