Monarch Butterfly

Description:

Every year, millions of Monarchs migrate from Canada and the US to overwintering sites in Mexico. These beautiful butterflies reach wingspans between 8-10cm, with males being slightly larger than females. The conspicuous orange and black colouration is aposematic, meant to warn potential predators of the fact that it is distasteful and poisonous. The females (picture #5) have darker and broader wing venation, while the males (picture #6) have lighter venation with narrower lines, and an additional pair of spots on the hindwing. These spots are on the vein closest to the abdomen.

Habitat:

Spotted in Sierra Chincua, in Oyamel Fir forests in the mountains of central Mexico (Michoacán). However, Danaus plexxipus has world wide distribution, with several subspecies being recognised.

Notes:

The overwintering populations in Mexico, come from populations east of the Rocky Mountains. The 'western' populations usually spend the Winter in California. The moderate climate in these Mexican mountains seems to be ideal for the butterflies, making this incredible journey worthwhile. The huddle together in thousands in order to maintain warm and conserve energy. One of the most fascinating facts of this unique migration is that the return journey spans 3-4 generations of butterflies. And still they're able to find their way! This year (2017) butterfly numbers were down from the previous year, but up from the record low in 2013/14. Because counting the butterflies would be impossible, population size is measured in hectares in which these insects roost. In 2017, colonies covered 2.91 hectares, in contrast to 2016's 4.1 hectares.