Do Aphids Eat Monarch Eggs?

Aphid eggs and monarch eggs can be quite often confused when investigating a plant as they will sometimes inhabit the same one. But are these two species compatible or do aphids eat monarch eggs?

The Quick Answer

Do Aphids Eat Monarch Eggs?

Aphids do not eat monarch eggs. Aphids, also, do not kill monarch eggs. Aphids only consume the sap from plants.

Do Aphids Kill Monarch Eggs?

Even though they often occupy the same plant, aphids will not kill monarch larvae or monarch eggs. They are not aggressive to the other creatures and they do not cause any direct harm to the monarch eggs. However, their presence can cause indirect harm. 

What Do Aphids Eat?

Aphids only eat sap that is produced by plants, so they do not eat monarch eggs. They will obtain this plant sap either through the roots, leaves or stems of plants. They have specialised mouth parts where they inject a needle-like structure into the plant to draw out sap.

Aphids would be unable to consume monarch eggs as they do not have the mouth structures needed to pierce animal tissue and they cannot bite.

Do Aphids Harm Monarch Eggs?

Whilst aphids do not harm monarch eggs or monarch larvae themselves, their presence does sometimes result in an indirect death of these monarch eggs.

Here are a couple of ways in how this may occur:

Removing Aphids Can Remove Monarch Eggs

If you are removing aphids from your plant, you may accidentally remove monarch eggs as well. Once they are removed from the plant they will not survive.

This most commonly happens when people are using hoses to spray aphids off their plants and unfortunately many monarch eggs get knocked off in the process. 

Killing Aphids Can kill Monarch Eggs

There are a number of ways in which you can kill aphids and their eggs, but you need to be careful, these methods can also kill monarch eggs.

For example, some people use an alcohol spray to kill aphids, but alcohol is also a killer of monarch eggs. Instead of using a spray. Dab the aphids directly with a cotton bud soaked in alcohol to be more precise when killing the aphids. 

Aphid Predators Eat Monarch Eggs

Where there are aphids, there are aphid predators. Ladybugs are primary predators of aphids and will often return to plants that aphids inhabit to get their food.

One problem with this is that as well as aphids, ladybugs will prey on both monarch eggs and monarch larvae.

So, whilst they are very useful for controlling aphids and maintaining a healthy ecosystem, they also put the monarch eggs in your garden at risk. 

Do Ladybirds Eat Monarch Eggs

The Difference Between Aphid Eggs and Monarch Eggs

To make sure that you do not remove or kill the wrong set of eggs, here are a couple of points that will help you to tell the two apart. 

Monarch Eggs

Monarch eggs are laid by monarch butterflies on milkweed plants. They are circular in shape and off-white in colour.

Usually, monarch eggs are planted alone rather than in big clusters and they are often found on the underside of leaves but can also be found on flower buds or stalks. Monarch eggs are around the same size as fully grown aphids. 

What Do Monarch Eggs Look Like

Aphid Eggs

Aphid eggs are much smaller than monarch eggs and are usually laid in big clusters on the underside of plant leaves.

Aphid eggs are usually more difficult to spot as they will be coloured to blend in with the plant leaves, often making them green or yellow in colour. Some species of aphids also cover their eggs in a layer of wax that looks white and stringy when investigated under a microscope. 

Monarch eggs are only found on milkweed and the only aphids found on milkweed are oleander aphids that are yellow or orange in colour. If there are eggs on any of your other plants, then they will not be monarch eggs. 

Final Summary

To summarise, aphids do not eat monarch eggs or monarch larvae. Aphids only eat sap produced by plants. Aphids do not kill monarch eggs, but aphid removal methods and aphid predators have been known to also kill monarch eggs.

Monarch eggs are white and are larger than aphid eggs. They are usually found alone or in very small number rather than aphid eggs which are tiny and are laid in big clusters on the undersides of leaves. 

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