The Dung Beetles are minor characters in the series that appear every now and then in season. They become more major in the episode "Revenge of the Small Fries" where 4 Dung Beetles struggle to roll a ball of dung and Oscar helps them. They offer Oscar their might to get him a bannana from the Trio, which he failed to get before helping them, all appears to be going well, when Oscar is discovered helping them and is knocked out while the beetles are trapped. Oscar however rescues them making them even more grateful to him.
But he's captured by the Trio and the four retreat. Later we see Oscar in a cage with the Trio asleep when Popy is awoken by a sound she looks to see the dung beetles only to realize that a whole army of them had come to rescue Oscar and punish the Trio. They give a grateful Oscar the bannana and they become allies though this alliance isn't ever shown again.
They are oscar's friends in the show they also help oscar in many things.