Re: How can the Monarch butterfly sustain the flight to Mexico without food?

Hi Allan,

Some years ago, I was crossing the mid-west and came across a line of Monarchs flying south for the winter. I looked both north and south; the line of butterflies extended as far as the eye could see in either direction over this vast flat land. It is one of the most spectacular events that I have been lucky enough to witness.

I am not sure where you learnt that Monarchs fly all the way to Mexico without food, but I don't think that it is true. I came across at least one website putting out totally spurious information about the Monarch migration. (See below for a great website)

The Monarchs stop to feed in the southern United States and actually gain weight on the trip. The butterflies that arrive in Mexico typically consist of 50% body fat by mass, which must sustain them through the winter. One area of research, which needs to be completed, looks at to what extent and how monarchs conserve energy during migration. If you have any further questions about monarchs, then try the reliable and excellent Monarch Watch site, or continue posting questions to the mad entomologists on this site.

Richard Kingsley