Few metamorphoses are as dramatic as the one experienced by the Monarch butterfly (
Danaus plexippus), which are a welcome sight during the summer across the many regions of Canada. Its beautifully patterned black and orange wings easily make the species one of the most recognisable butterflies found in North America; however, this iconic form is only attained during the final stage of its life cycle, after it sheds its brightly striped caterpillar form and develops within the safety of the chrysalis that encases it.
The process begins when the caterpillar spins a silk pad on the underside of a milkweed (
Asclepias) leaf and attaches its hind claspers to it. Now suspended with its head facing downwards, the caterpillar's life depends on the strength of this attachment. Twisting around, the caterpillar sheds its skin to reveal a moist exoskeleton that hardens to a waxy, green-coloured coating. The chrysalis darkens and becomes transparent over the course of nine to 15 days, during which time the pupa develops inside. The butterfly soon emerges (after approximately 10 days with a little assistance from gravity as it pushes down and outwards to split the chrysalis. Now free, the butterfly will rest on its former enclosure while expanding its wings in preparation for its first flight.
Did you know…
• Many think of a butterfly chrysalis as a "cocoon" but this isn't accurate – a chrysalis is made of protein (like the caterpillar's skin) while a cocoon is made of silk and is often associated with moths.
• The milkweed (
Asclepias) is both home and a food source for the Monarch caterpillar. It will eat nothing but milkweed leaves day and night until it becomes a chrysalis, and then will not eat again until it emerges as an adult butterfly. The milkweed also protects the Monarch – its toxins build up in the caterpillar's system, meaning the Monarch will be poisonous to many predators for the rest of its life!
Specifications
- No. 130534
- Mintage 10000
- Composition fine silver (99.99% pure)
- Finish proof
- Weight (g) 7.96
- Diameter (mm)27
- Edge serrated
- Certificate serialized
- Face value 3 dollars
- Artist Trevor Tennant (reverse), Susanna Blunt (obverse)