Transformation of a monarch

It is always fascinating to see the transformation of invertebrate life. In my opinion, there is no more interesting example than to follow the development of a butterfly, and in this case, the Monarch butterfly.

The following images weren't all taken in the last few days, but many of them were. This first one shows an adult female with the tip of her abdomen turned up to the underside of a milkweed leaf as she lays an egg.

 The egg is very small, as to be expected. It is only a couple of millimetres in diameter.

 After a few days, it hatches (hopefully!). Ants are known to find and consume the developing larva, so not all eggs will hatch. Upon hatching, the larva consumes the remains of the egg and will chew a small hole through the leaf.

 This next one shows a larva that is probably 2-3 days old. It hatched out on a small milkweed plant that I was growing from seed in some plug trays.

 Over the course of several days it feeds ravenously.

 After several periods of growth, it gets to the point where it seeks out a place to change to its pupa stage. This usually is in a more obscure location, and often happens well away from the milkweed plant. The caterpillar hangs upside down with its hind end producing a sticky mass of threadlike substance which will provide an anchor, holding it in place while it develops into the adult. While hanging upside down, the caterpillar splits its skin and wriggles out of it, revealing this beautiful chrysalis of the pupal stage. It is decorated with black and gold spots.

When the above photo was taken, it shows a slight darkening of the chrysalis at the bottom. Just before the adult emerges, the outer part of the chrysalis turns clearer and somewhat brown. A close look will show some of the detail and colour of the newly formed adult inside. I wasn't expecting it to happen quite so quickly, and so I missed that part! This next photo was taken less than 24 hours after the one above. The new adult emerges and climbs a bit to a surface where it can hang for several hours while its body fluids are pumped into the venation network making the wings rigid.

 Usually within 4 or 5 hours of emerging, the butterfly is able to take flight and will hopefully survive to continue the propagation process.

It truly is an amazing transformation!

Now that the end of August is close at hand, over the next few weeks, Monarch butterflies will be heading south and west by the hundreds of thousands, on their long journey to the wintering ground in some Mexican mountains. In southwestern Ontario, the peak of their migration seems to occur from about the middle of September to the end of the month, although some individuals can be seen up to the end of October or even after. It all depends on when the latest generation emerges as an adult, which is somewhat weather related. Corridors of natural vegetation and lots of milkweeds are critical for the butterflies to make it to Mexico as well as for future generations to return.