PLAGUES of poisonous and cannibalistic ladybirds are making their way into homes across the News Shopper area. The brightly-coloured harlequin ladybird will bite humans when hungry – leaving behind an itchy lump.LAGUES of poisonous and cannibalistic ladybirds are making their way into homes across the News Shopper area. The brightly-coloured harlequin ladybird will bite humans when hungry – leaving behind an itchy lump.