Numerous fungi, bacteria and small animals attack spruce needles that fall to the ground. They feed on the needles until only scraps remain – a good example of how decomposition occurs in nature.
Thin fungi hyphae intrude into the needle, break it down and absorb nutrients and energy. The needle becomes hollow.
The needle is now accessible to mites, millimeter-large creatures. The female box-mite lays her eggs in the needle's cracks.
Young mites hatch after some time. The needle becomes their nursery, offering shelter and food. The young mite's development can take up to two years and entirely within the needle.