grasshopper
螽 centers on a grasshopper, a specific kind of insect.
螽 combines 冬 (winter) on top with 䖵 (two insects) on the bottom. The exact historical reason for this combination is uncertain, but it may relate to the grasshopper's seasonal appearance or a phonetic role of 冬.
Two insects 䖵 huddle together under a winter 冬 sky, like grasshoppers seeking warmth before the cold.
For シュウ, imagine a grasshopper making a soft 'shoo' sound as it leaps away: shoo -> シュウ, and the grasshopper disappears into the grass.