Beetle larvae are found inside whole grains, so you won’t spot those until you see the adults in the bottom of the packet. That applies to Sitophilus oryzae, the “rice weevil”, for instance, says Associate Prof Rob Emery from Murdoch University.
‘Kind of like Gonzo from the muppets’: Sitophilus oryzae, commonly known as a grain or rice weevil. Photograph: Adid Jimenez/Getty Images/EyeEm
“It uses the snout to bore into the grain, turns around and lays eggs in the opening and seals the hole,” he says. “The egg hatches into a larvae, then generally stays inside the grain until it pupates.”