Every fall, millions of monarch butterflies leave their summer homes in Canada and the northern United States and travel over 3,000 miles south to their winter home in the mountains of central Mexico.
Even though the journey is long and arduous, instinctively, the butterflies know that they need to find a safe place to spend the winter. This makes sense. But what is very unusual is how the butterflies make their spring return trip to their breeding and feeding territories in Canada.
You see, the individual butterflies that leave the north are not the ones that will return. While favourable air currents permit the monarchs to make their way south to Mexico relatively quickly, the return trip to northern climes takes much longer. In fact, because the life cycle of a butterfly is just 5-7 weeks, individual monarchs stop for breeding and feeding cycles, and eventually they die before completing the journey.
However, their offspring continue the journey. Eventually, it takes the monarchs four to five generations to actually make the entire trip back up to Canada.
We still don’t know why …
Science is still deciphering how an individual monarch knows to return to the summer breeding and feeding grounds from several generations ago. Is it Continue reading