I've noticed these little swarms of bugs on my trees a few times.
They're fun to bother; when I get too close, they avoid me but they stay
together in a group while they run. Sometimes I can poke right in the
middle and they form a bug donut shape.
I think that these psocid bugs graze on the lichen that grows on the
tree bark. They prefer the shadows; when I try to nudge the group to the
sunny side of the tree for pictures they don't cooperate at all.
The adult bark lice are dark with narrow yellow lines and a white spot
at the back of each wing. When you peek at them from the side you can
still see the stripes that the nymphs display.
The bark lice scampered over some interesting looking
while they were running away
I've found these bark lice, also called barklice and Psocids, on my
and Wild Tamarind
trees. I have more lichen
Purple Jacaranda, but it's a smaller tree with little crown so it's
probably too sunny for these tiny bugs