It’s a commonly known fact that Monarch caterpillars like to feed on milkweed and they’ll rarely eat any other plants. But, is this the case for Monarch caterpillars only or do all caterpillars eat milkweed?
No, not all caterpillars eat milkweed. The monarch caterpillar is well-known for consuming milkweed but there are plenty of other caterpillars who eat it too!
It’s easy to identify a Monarch caterpillar due to its distinctive yellow, black and white stripes on its body and two black tentacles on either side. You can spot these types of caterpillars easily on milkweed plants.
Yes, Monarch caterpillars will generally only eat milkweed providing that milkweeds are available, of course. Planting milkweed is a great way to encourage Monarch caterpillars and butterflies into your garden.
Monarch caterpillars will only eat milkweed. They will not eat other plants in your garden. Therefore, if you want to encourage monarch caterpillars and then butterflies into your garden you’ll need to plant milkweed.
Which Caterpillars Eat Milkweed?
Milkweed plants generally aren’t a favourite food source for many animals as their white sticky sap (where the milkweed’s name comes from) is toxic, and also the leaves are filled with toxins called cardiac glycosides.
This toxin prevents animals and most insects from eating the plant, so only a couple of types of insects that evolved a way of dealing with the toxins without being poisoned can eat the milkweed plants.
Monarch caterpillars are mainly the only caterpillars that consume milkweeds as their only source of food, but there are also other, slightly less common, caterpillars that like to eat milkweed:
Striped Garden Caterpillar
Striped garden caterpillars can sometimes be seen eating milkweed plants. Still, unlike Monarch caterpillars that only feed on milkweeds, striped garden caterpillars can eat other plants such as yarrow, grasses, goldenrod and clovers.
The striped garden caterpillar pupates into becoming the striped garden moth. It’s a small grey moth with tiny diamonds on its wings. The striped garden caterpillar is a black caterpillar with yellow stripes.
Milkweed Tussock Moth Caterpillar
The fuzzy and fluffy milkweed tussock moth caterpillar depends on milkweed plants as their primary source of food. The caterpillar is black and orange in colour. The milkweed tussock moth caterpillar basically looks like a crawling colorful hairbrush if you see it from a distance, it’s that hairy.
Meanwhile, the adult caterpillar, which is the milkweed tussock moth, displays a similar colour combination of black and orange on its body while its wings are a dull greyish colour. This bright yellow and black combination of colour on both the caterpillar and the moth notifies their predators that these insects are distasteful and are toxic upon eating.
The bright colours are a defensive mechanism so predators will stay away.
The caterpillar’s hair is dense, and as mentioned earlier, it looks like a hairbrush because of all of its fluffy and thick tufts of yellow, white or black hair. This is how you can identify the caterpillar through its colourful protrusions on its body.
The endangered Cycnia Inopinatus is another type of moth larvae that is very unusual looking and likes to feed on milkweed plants. It’s a moth that belongs to the family of Erebidae. It’s usually seen in the US. It pupates into a Cyncia moth, and its diet mainly consists of milkweed.
Do Monarch Caterpillars Eat Anything Else?
No, monarch butterflies only eat milkweeds from the Asclepias family and won’t eat any other plant. They specifically prefer milkweeds over anything else. The monarch butterfly is also called the milkweed butterfly due to its favouritism of milkweeds over any other plant.
The milkweed plant has all the nutrients and nourishment necessary for the monarch caterpillar to pupate into the adult monarch butterfly.
Unfortunately, these plants are reducing in numbers at a concerningly high rate. Their sudden increase in loss is due to habitat stemming because of more and more land being used for commercial and residential buildings and because people spray weed killers on the fields where they usually grow.
Milkweeds aren’t just one plant. They’re a diverse family of varying types of milkweeds. There are a couple of types that can thrive in full sun. Some grow in humid temperatures and can even grow in dry places. They grow every year, even in harsh winters. They have pink flowers and are preferred specifically by monarch butterflies.
Milkweed plants are the preferred food source of monarch butterflies and monarch caterpillars. The caterpillars solely depend on milkweed plants to provide them with enough food and nourishment so they can pupate into monarch butterflies.
Milkweeds are toxic, and due to this reason, animals and many insects stay away from them, but only a few insects feast on milkweeds, and several of them are caterpillars. Not all caterpillars will eat milkweeds, but the monarch caterpillars aren’t the only ones that will feed on them.
Ryan is a keen gardener from the UK who’s spent years dealing with countless, common pests over the years so knows the ins and outs of how to deal with pests in the garden