If you are sure they are ladybugs and not asparagus beetles then there must be something on the plants that they are feeding on. I've seen ladybugs feeding on asparagus beetle larvae in my garden.

Is there a time of year where you are when they start to congregate to hibernate? Perhaps your asparagus are near a good hibernation location?

As noted above, the #1 issue right now is whether they are really ladybugs. Asparagus beetles resemble ladybugs. You say you don't see the former, so that suggests that you know the difference. But be careful.

Please post picture or two to help settle this discussion.

Sorry I couldn't get a clearer picture, but it was windy today. What do you think? Ladybugs or asparagus beetle?

Ladybugs are round. Asparagus beetles are elongated. BUT, what I see here is more like a ladybug larva. See the bottommost picture on this website -

http://gardenmentors.com/garden-help/wildlife-2/asparagus-beetle-id-easy-control/

Those look like ladybug nymphs in various stages of development to me. I see white flecks on the asparagus fronds, which are probably honeydew and/or shed skins of aphids. My dill looked exactly like that when it got a bad aphid infestation one year. I think they're there chomping up your aphids or some other sap-sucking insect that leaves honeydew.

Wow, I didn't even notice the honeydew! So should I spray for the aphids, or leave the ladybugs to their work? Thank you!

Agree with Dave. Even organic pesticides like neem and DE will harm predators, too, and create conditions for later pest overpopulation, so I'm sparing with these. I don't do anything for aphids unless the problem starts looking like it's in danger of getting out of control, in which case I wash some of them off the plants with a stream of water from a good squirt bottle or, depending on how tough the plant is, a blast from the hose. They're either killed by the force of the water or have a hard time making it back onto the plants. It's very effective. I don't do anything about a general low-density population of aphids. They're usually kept in check fine by hoverflies, parasitoid wasps, ladybugs, lacewings, etc. if you have a garden or yard that supports these predators, trying to eliminate aphids entirely just makes everything worse in the long run.