another terrarium-related thread?
personally, i would ask this question on your observation rather than in the forum. you’re more likely to get someone who knows what they’re talking about looking at your observation.
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that said, even if you can’t find info about a particular species, you can look for information about the genus or family, and that may tell you all you need to know. members of the family appear to be generalist predators.
you can also look at GLOBI, and that sometimes has useful info, if you can’t find any other information. for example: https://www.globalbioticinteractions.org/?interactionType=interactsWith&sourceTaxon=Prostemma.