A locust swarm can form when crowded grasshoppers change both behaviour and colour.

The longer version

Crowding triggers changes in these grasshoppers because frequent physical contact alters hormone levels, and those hormones reshape development across generations. The same species essentially switches between two ways of living, with newly gregarious individuals becoming busier, brighter, and far more inclined to travel together.

Colour shifts from green toward yellow and black, reflecting different chemistry in the outer skin. Moving in a band offers some protection, since animals in a group are less often targeted alone. When rains produce abundant green growth populations build, and once vegetation dries they concentrate and move onward. Winged adults can cover long distances when warm air currents carry them over unsuitable ground.

Where this entry sits

This collection gathers small wonders from the world of ants, bees, butterflies, beetles, and spiders. Expect surprising details about swarms, silk, and metamorphosis, plus the strange everyday abilities of creatures small enough to fit on a fingertip. The full list sits on the Insects and Spiders page, where every entry is listed in order.