Looks like what we call rolly polly around here. We usually find them under pots. Never seen one on the the tree eating green leaves. They don't do that. They like to hide away in the moist areas, in the dark, eating dead stuff. I'm not a bug expert so I'll let other say if they are harmful and how to get rid of them. I have never worried about them, but I usually dont find them with my citrus containers.

Also known as pill bugs (scientific name Armadillidiidae) because, when frightened, they roll up into a little ball. They eat rotting vegetation and are harmless. I think they are cute.

They are harmless They turn dead plants into insect manure through their digestive track.

Steve

And as a side note, these sow bugs are also not really "bugs" (or insects) but are (ancient-descended) crustaceans and have gills.

Yup Steve. Put it under water and.... IT LIVES (and crawls around)!!!!!! :-D

Steve, you crack me up!

I will leave them be as long as they don’t grow up to be a half crustacean half man creature.

Do they eat plant roots?

My calamondin is not doing well and I’m trying to figure out what it is. What could be eating the leaves and causing the yellow spots?

They eat dead mater only and are no threat to your trees.

Steve

I found a cool site that lists a number of common garden pests in Australia (includes those that can impact citrus) - https://blog.fantasticgardenersmelbourne.com.au/common-garden-pests-australia/

You may have a couple of things doing something to those leaves.

Those guys are harmless. I grew up in humid Crimea and they were everywhere. Kids call them autobuses :)

I rarely see them in California (where I live at least).

The presence of pill bugs in you plant may be an indication that your soil is too moist for too long.