Mosquitoes find people partly by sensing the carbon dioxide in human breath.

The longer version

Carbon dioxide acts as a long-distance clue because every breathing animal releases it in a steady plume. Sense organs on the antennae detect even slight rises above the ordinary background level, prompting the insect to fly upwind toward whatever is producing the gas.

As distance closes, other cues take over: body warmth, moisture, skin odours produced by bacteria, and dark shapes against the surroundings. Layering several signals in sequence is efficient, since each works best at a different range. Only females take blood meals, needing the protein it supplies for their eggs. Males generally feed on nectar and plant juices instead, visiting flowers mainly for sugar.

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.