Well, Shiver Me Butterflies!

One method of thermoregulation in monarch butterflies is shivering. Butterflies can vibrate their wings in place which causes their flight muscles and thorax to warm above the external air temperature.



Butterflies and some other poikilotherms ("of varying temperature") have some methods of adjusting their body temperatures. Monarch butterflies, like the one pictured in the video, will also bask in sunlight and allow the solar radiation to warm the haemolymph (circulatory fluid of certain invertebrates) that runs through the veins in their wings, basically using their wings like solar panels. Basking with the addition of shivering can raise the temperature of a monarch so that it can fly even though external temperatures might be prohibitive.

The article Thoracic temperature, shivering, and flight in the monarch butterfly, Danaus plexippus (L.) from The Journal of Comparative Physiology (April, 1970) showed that a monarch butterfly shivering its wings at 59 to 60 degrees Celsius could raise its temperature at 1.3 degrees Celsius/minute reaching a thoratic temperature of 4 degrees Celsius greater than ambient temperature. At higher temperatures the butterflies could warm themselves faster and to an even greater temperature above ambient. Pretty cool!

Video by MOSI Outside volunteer Jill Staake