We never saw them before, this morning they appeared on a weed plant. The leaves of the plant have some minor holes, but my guess is those were already there.
The biggest ones are about 1 centimeter long. They move slowly. With such bright colors they attract attention, which is quite remarkable. We're in the tropics, 1200 m / 3600 ft altitude. Does anybody know what type of insect this is?
These are nymphs of some sucking insect aka "bug" - so they won't make holes. There are tons of different kinds of sucking insects - we have a horrible kind here, the Kissing Bug, which drinks blood! Some other bugs attack other insects. Most are attracted to specific plant families.