Great spotting Santhosh! I think this is one of the “Seed bugs” and the nymphs & adults feed on the sap of the seeds. A popular seed bug is the Milkweed Seed bug and their host plant is the toxic Milkweed plant, so maybe your bugs are getting theirs from the Oleander seeds. This is just my hunch, so keep and eye out on them in the coming days and see what they are eating 🙂