Not much has been going on lately with these. Of the females that I captured and put in a small hatching tank, neither has done anything yet. One of them, the one that had only a very few eggs to start with, has either dropped or hatched her eggs without me noticing, so she was returned to the main tank.
I did another full rescape today after discovering that floramax contains chips of carbonate rocks (they fizz wildly in vinegar) and has almost certainly been the source of my pH/KH headaches in that tank lately (numerous lost batches of bumblebee shrimp eggs and 0 surviving baby bumblebees in the last 2 months...) In the process of moving everything I was more concerned with speed than doing a proper head count, but it appears that most, if not all, of the crabs have survived to this point. I checked each as I moved them, and checked size, sex, and berried status. Of the females, all but 3 were berried. I left 3 berried females in the main tank and transferred the remaining berried females to my hatching tank to see if I could finally get some zoeas. I've seen numerous instances of mating behavior lately, so it seems likely that conditions are good for them to reproduce. Hopefully now that I rescaped I didn't mess things up overly much.
I've noticed a few things about these animals. I would like to be perfectly clear that these are just my observations and that it's entirely possible that they would be proven wrong with a larger or more representative sample of the animals.
Sexual dimorphism: Males appear to grow substantially larger than females. Of the crabs I have, the 5 largest are males, and they are larger by far than any of the remaining crabs. I have very few small males, and it seems likely that the small males that I have are young animals. The males also have much heavier claws and are much more setose (aka hairy.)
Color: RandomMan noted this in another microcrab thread recently. Microcrabs kept in soft, acidic water tend to turn gray. If they are kept in hard, basic water, they tend to turn brown.
Temperament: Peaceful, entirely so. The most aggressive acts I have seen involved mating, when the males occasionally use their claws to hold a female's leg, or when several microcrabs are in the same small container (as in shipping) they will tend to grab onto one another and form a crab ball. They disengage from the ball without injuring one another, however. While rescaping I tried repeatedly to get a crab to pinch me, they just wouldn't do it. I believe that one of my largest males managed to get me once, but his claw power was so weak that I am not certain whether that was what was happening or not.