Editing Dragonfly (section)

=== Temperature control ===

The flight muscles need to be kept at a suitable temperature for the dragonfly to be able to fly. Being [[Ectotherm|cold-blooded]], they can raise their temperature by basking in the sun. Early in the morning, they may choose to perch in a vertical position with the wings outstretched, while in the middle of the day, a horizontal stance may be chosen. Another method of warming up used by some larger dragonflies is wing-whirring, a rapid vibration of the wings that causes heat to be generated in the flight muscles. The [[green darner]] (''Anax junius'') is known for its long-distance migrations, and often resorts to wing-whirring before dawn to enable it to make an early start.{{sfn|Berger|2004|pp=44–46}}

Becoming too hot is another hazard, and a sunny or shady position for perching can be selected according to the ambient temperature. Some species have dark patches on the wings which can provide shade for the body, and a few use the [[obelisk posture]] to avoid overheating. This behaviour involves doing a "[[handstand]]", perching with the body raised and the abdomen pointing towards the sun, thus minimising the amount of solar radiation received. On a hot day, dragonflies sometimes adjust their body temperature by skimming over a water surface and briefly touching it, often three times in quick succession. This may also help to avoid desiccation.{{sfn|Berger|2004|pp=44–46}}