Most cold-tolerant insect (aquatic)

The world's most cold-tolerant aquatic insect is the Weddell sea louse (Antarctophthirus ogmorhini). As its name suggests, this ectoparasitic insect's host is the Weddell seal (Leptonychotes weddellii); it attaches itself to hairs on the the seal's flippers, ankles and hips. Because this seal is an Antarctic species that spends much of its time each year swimming below the ice, the louse is almost constantly subjected to subzero temperatures – i.e., as low as -2°C (28.4°F).

The most cold-tolerant insect overall is the larva of the red flat bark beetle (Cucujus clavipes puniceus), native to Alaska, USA. Some populations in the wild state have been seen to remain unfrozen at temperatures as low as -80°C (-112°F). Moreover, under laboratory conditions these beetle larvae were found to survive unharmed at temperatures as low as -150°C (-238°F)