How do worms appear in compost heaps? (or anywhere else?)

[Primrose]

I'm hoping there are some biologists here who can explain to me how works appear in compost heaps. There are obviously none when one starts to build a new heap yet by the time it's ready to be dug out, the material is full of them. How do they grow/generate and are they a special kind of worm.
Similarly one can have a patch of ground that contains no worms yet if you dig in humous, grass cuttings etc, the worms suddenly start to appear. I'm curious what kicks this process off, and is it a sign that your soil is more fertile if it hosts a lot of worms?

[FelixLeiter]

They crawl / inch their way there. Worms can travel quite rapidly, especially after rain showers. They are also distributed by eggs, which may be present in some materials put onto the compost heap. It's always recommended for a compost heap to have an earth base, for the worms to find their way up into it, but most of the worms involved in decomposition are different from those in soil.

Worms are indeed a good sign of fertility, demonstrating that the soil is rich in organic materials, which is what they eat.

[peter]

I can't afford to dig in humous, I use humus instead.

[Monika]

Relating to this question, another one (yes, I know that I asked that same question a few years ago!): what happens to the compost worms when we spread the compost onto the garden? Do they die? I even wrote to Wrigglywrigglers at the time with this query, but never got an answer.

Can you answer it, Felix?

[Primrose]

Well some of the worms that get dug out of my compost heap disappear rapidly down the gullets of the local robins as soon as I start spreading the stuff. . They always seem to appear from nowhere when this action is underway and hover close by looking for an easy snack.

[Flanjamin]

The worms that you get in your compost tend to be the red Brandling worms. Normal soil has a few of these, along with all the other standard earthworms. When you create a compost heap (or just leave a pile of something on the ground) these will be attracted to the waste, and then breed like crazy as they've found a good food source. When you spread the compost on the ground the ones that don't get eaten will go back into the soil, and carry on eating the stuff you've just deposited and living in the soil. Their breeding rate will reduce as there is less of their favoured food, and the soil population will eventually return to normal.

[Monika]

Thank you, FJ, that explains it nicely.

[Primrose]

So if I put a grass mulch around the base of my bean or tomato plants for example, I can trigger off the whole worm breeding process again? Presumably the breeding process also depends on soil temperature too?