Why didn't my butterfly eggs hatch?

We're often asked why someone's butterfly eggs that they brought in from their garden didn't hatch.  The bottom line is, in most circumstances, we don't know for sure!

[First photo; healthy Monarch egg]

But we do know several reasons why they perhaps didn't hatch. 

1.  The eggs were infertile.  Yes, females that do not pair will often still lay eggs.  After a few days, the eggs start to collapse on themselves, losing their plumpness and beauty.

[Second photo; infertile eggs after several days]

2.  Trichogramma wasps. These rascals are tiny!  They lay eggs in freshly laid butterfly eggs and the wasp larvae eat the inside of the egg.  Instead of a caterpillar, many miniature wasps emerge.

[Third photo; trichogramma wasp and Brazilian Skipper butterfly egg]

[Fourth photo; trichogramma wasps leaving a Giant Swallowtail buttterfly egg]

3.  Excessive Heat.  The eggs were in a spot that became too hot.  They should never be kept in a window or car.  Just like chocolate melts, eggs will cook. 

4.  Insect spray.  Eggs in a room that has had insect spray in the room can die.  NEVER use insecticide in the same room as butterfly or moth eggs, caterpillars, chrysalises, or adults.

[Fifth photo; Hatching Monarch caterpillar from a Monarch egg]

These are just four basic reasons why perhaps someone's eggs didn't hatch. 

There are several reasons why you may find your butterfly eggs empty or totally missing.  We'll cover those topics in another post. 

Skiff Moth - Prolimacodes badia

Prolimacodes badia

It's an unusual caterpillar that doesn't look like a caterpillar. It looks like a green box that moves. Small and cute, it moves slowly along leaves and stems. The rear of the caterpillar is pointed.


The Skiff Moth caterpillar eats oaks, winged elm, and other tree leaves. The pattern of brown on the caterpillar may vary from caterpillar to caterpillar.

The pupa is inside a tiny dark circle cocoon.



The adult moth is beige with a brown semicircle on its wings.

A Soft Chrysalis Falls ...

A soft chrysalis falls and you know that if it isn't hanging properly, it will be deformed. A deformed chrysalis means either a dead or deformed butterfly.

What do you do?

If you are nearby, you can save it!

One of the new pages on our educational butterfly website details how to save it.

It's super easy - anyone can do it! Just click on the link above to see photo instructions.

Fertilizer NPK - What does it mean?

You're planting a new garden or adding new plants. OR your plants are turning yellow or not blooming. Or ... anyway, you decide you need fertilizer for your garden.

You stand and look at the fertilizer containers which carry three numbers and wonder ... what do they mean?

The newest webpage on the site is about fertilizer numbers and soil pH and why they are important.

Silk Moth Mouth?

Silk moths emerge as adults without mouths. Imagine - they emerge, spread and dry their wings, mate, females lay eggs, and they die. They starve to death. The Luna Moth (above) is the beauty that is used in Lunesta commercials.


The caterpillar of the IO moth will sting - badly! But the adult is a beauty. Named for it's 'eyes' on its hingwings, it does not have a mouth when it becomes an adult.


Cecropia moth caterpillars start black, turn yellow, then turn green. Growing to 3" long, they make a cocoon, pupate into a pupa, and emerge as a huge beautiful moth, wihtout a mouth and cannot eat.


The Polyphemus moth is a huge brown moth. The spots on its wings are clear as glass. Again, the adult moth does not have a mouth.

Raising these moths are fun. The caterpillars do eat a ton of food - be prepared!

Dogbane vs Milkweed

Can you tell which plant is dogbane and which is milkweed? Dogbane doesn't grow in Florida but in areas where it does grow, many people use it to 'feed' their Monarch caterpillars, thinking that it IS milkweed. The result is starved caterpillars. Monarch caterpillars will not eat dogbane.

The plant on the left is dogbane and the plant on the right is common milkweed. Both have white sap.

Milkweed has hollow stems and dogbane has solid stems (thank you Jodi and Linda for these tips). Common milkweed has green stems while dogbane has red stems.



The flowers resemble milkweed in this species of dogbane but it is not the exact same flowers. Some species of dogbane grows flowers that closely resemble milkweed flowers.

If you're not sure, send a photo to someone who knows the difference. Remember, feeding dogbane to Monarch caterpillars (or rather, attempting to feed it to Monarch caterpillars) is a sure way to starve them to death!

At Shady Oak Butterfly Farm we use tropical milkweed exclusively. We're jealous! We'd love to have the larger leaves of common milkweed but it won't grow with our warmers winters - it needs cold winters.

Aphids and Ladybug Nymph

Ladybugs (known also as Lady Birds) are quite handy little critters in a garden with aphids. Aphids are well known as the enemy of milkweed. A few won't cause harm but they multiply like crazy - those aphids. Once there are more than a few, they can cause harm to your milkweed plants.



Adult lady bugs also eat aphids.

While watching Monarch caterpillars eat milkweed today, I saw the nymph running around. A short while later, it was eating lunch.

~Edith
Shady Oak Butterfly Farm

What is Going On Inside a Monarch Chrysalis?

There is a lot of action going on inside a Monarch butterfly chrysalis.

We assume that the inside is just 'mush' but it isn't mush. It is soft and tender and easily damaged.

A large caterpillar already has wings - so to speak. They are called 'wing pads' and are already growing into wings. (Swallowtail caterpillars can be identified by the wing pads alone when the wing pads are viewed under special lights.)

This freshly pupated Monarch chrysalis is labeled. Wings, proboscis, legs, eyes, and antennae are clearly identifiable at this stage.  (The arrows are slightly inward for the eyes in this photo.  The eyes are a little lower and further out.)

The proboscis is seen as two lines. These two lines are two tubes that are forming. When the adult butterfly emerges, the proboscis is two tubes that the adult must fuse together into one proboscis.  They zip together and create a channel between the two; the channel is the 'straw' through which the butterfly drinks.  Each side of the proboscis is a 'tube' that has blood flow, nerves, trachea, muscle, and more.

The chrysalis cannot see although the eyes are also forming.

As a caterpillar changes into a chrysalis, it is extremly active. Some species of butterfly chrysalises are super active, moving every time something touches it. Red Admirals and Painted Lady chrysalies are notorious for their activity in their chrysalis stage. 'Mush' doesn't move - it requires structure to move in a co-ordinated fashion to first, work the cremaster tightly into its silk pad and knock off its old skin and two, to knock off or discourage parasitoids and predators.

As the chrysalis changes shape and hardens, these parts are less visible. Although less visible, they are still clearly identifiable.

If a soft, freshly pupated chrysalis falls, some of its organs can be seen in the resulting 'splat'. Yes, a fall kills a soft chrysalis.

In most cases, a hardened older chrysalis can fall for several feet without damage. If the emerging adult butterfly is not on a smooth surface and can obtain a grip on something wtih its feet and climb up on something to hang (to expand it's wings), it will also live and become a normal adult butterfly.