By Jo Marshall, CVT
Senior Veterinary Information Specialist at Pet Poison Helpline
I don’t think that I am letting out any big secret when I tell you that I work with geeks here at Pet Poison Helpline. It is true we are all a bunch of geeks! I don’t mean the technology obsessed kind of geeks; the group I work with are more the kind of geeks that are obsessed with animals. Oh – and let’s not forget, we are all a little weird or geeky about poisons and toxicology here at our place of work. I know you are now wondering where this blog is heading so just hang with me here while I share one of our favorite summer time animal geek activities and a little of the poison trivia that seems to float around our office.
For a few years now, many of our staff has been actively involved in Monarch hatching. This year Dr Ahna Brutlag, our esteemed Associate Director of Veterinary Services, took this particular hobby to a whole new level (see this is where the animal geek title is earned – sorry Ahna)! But we all got to enjoy this hobby with her as she shared the progress of her little caterpillars. I thought it would be fun to relive the hatching of the Monarchs as we move into late fall and the soon to be frozen tundra of our Minnesota winter.
- So this is day 1 of the caterpillar. This little guy started his life as a very small, cylindrical egg. These eggs are laid on leaves of plants, in the case of the Monarch, on the leaves of the milkweed plant. The adult butterfly lays their eggs on the leaves of the plant that they need to eat so that as soon as the larvae comes out of the egg, they can start their job – eating, eating and more eating! This larvae stage is the second stage in the life cycle of the Monarch butterfly.
- This is Day 4 of the little larvae.Obvious growth as milkweed leaf after milkweed leaf is devoured. The interesting thing about the growth of caterpillars is that their skin does not stretch or grow. As they grow, they molt and shed the outgrown skin or exoskeleton several times during their life as a larva. I think one of the trivia facts that Dr Brutlag shared with us during this phase is that the larvae grows something like 50,000 times their original size. Yikes – that is a whole lot of eating milkweed leaves! And this leads to inventions such as the milkweed leaf holder pictured below.
- Here is day 13 and they are quickly getting ready for the third stage of their life, the pupa stage. They have reached their full length and weight and the caterpillar is becoming chrysalis.
- You can almost see the wings through the cocoon or chrysalis. They are in this stage from day 14 to day 26 and then the magic starts! With close monitoring, you can watch these beauties come out of their cocoon. Their wings are very soft and flexible as they emerge. Their vibrant wings gently unfold in preparation of flying. Within 3 to 4 hours of hatching, they will master flying.
So now it is time for the toxicity part of this tale. The milkweed plant that the Monarch butterfly feeds on is toxic. There are approximately 76 varieties of milkweed in the United States that all have varying levels of toxicity. Milkweed tends to be a concern primarily in grazing animals such as sheep, cattle and horses. These poisonings occur in pastures or corrals that are over grazed and have nothing more for the livestock to eat. Interestingly, milkweeds are also toxic to poultry and birds. Milkweed becomes the Monarch butterfly’s protection against their primary predator, birds. The cardiac glycoside (the poisonous property of milkweed) is actually collected in the Monarch’s body making them poisonous to the birds that ingest them. Birds poisoned by eating Monarch’s have learned over time to avoid them.
So there you have it! A tale of toxicity and proof that animal geeks are alive and well here at Pet Poison Helpline!