Tuesday, May 26, 2015

Raising Wild Silkmoths: Pt. 1

One of my hobbies as a park Naturalist has been capturing and raising various moth species.

Moths in the Giant Silkmoth family are easy to spot, and if you happen to find a female during the daylight hours, she has likely already been bred and is ready to lay her eggs. All you have to do is put her into a paper bag to collect them!

But how do you tell male from female?

Males have much larger antennae, for one thing. They use them to detect pheromones the females release - which is how they find each other in the darkness.

Notice how much fuller the male's antennae are when compared to the female's:

Females are usually larger than the males, with a much larger abdomen (full of eggs!).

Some species are sexually dimorphic - meaning males and females are different colors. Probably the most strongly sexually dimorphic species occuring around here is the Io silkmoth.

These photos are not to scale, by the way - the female is noticeably larger than the male.
Both have the distinctive large eyespots on their hindwings, but males are bright yellow and the females are reddish brown.

It will be awhile before many of these species start making an appearance, but you can look for them around porches, tennis courts or anywhere there are bright lights.

Our Regional Interpretive Specialist usually makes the rounds with captive raised Cecropia Moth Caterpillers every summer.

They make a great educational tool for the Seasonal Rangers, and the adult moths get released into all the state parks (Cecropias have become less common in recent years).

Last summer's Cecropias over-wintered in their cocoons on our front porch, and have been emerging one or two at a time for the last several weeks.

It just so happens that yesterday a male and female emerged at the same time!

So I decided I would go ahead and collect eggs from her so this summer's Seasonal Ranger would have some caterpillars to program with.

The process is quite simple.

I just tossed the couple into a paper bag, where they soon decided their intimate relations were over.

I went ahead and released the male.

Hopefully he was able to find another Cecropia girlfriend out there before his life ended.

Many moth species spend a very short amount of time as adults. In fact, a great majority of them don't even have mouthparts since they don't eat anything. They rely on the food stores they accrued during their life as a larva.

Within the space of a week, they emerge, mate, lay eggs and die.

So I left the female closed up in the paper bag overnight, and this morning found that she had laid her eggs.

I went ahead and released her, but having fulfilled her one and only purpose, she likely perished shortly thereafter.

Now it is time to collect the eggs.

I simply tear open the bag and cut out the areas where the eggs are attached.

They are stuck on there pretty good, so this way you don't risk damaging them by trying to pry them away.

Then I just take the leaflets and close them up in a plastic bag.

The bag will help protect them from predators and the elements, while also insuring they don't all wander off when they hatch.

The bag will sit in a protected spot on my porch until they hatch, which will be in 10-14 days.

Stay tuned for what comes next!

In the meantime, I'll show you a few more giant silkmoth species you may encounter.

The Luna is probably the most recognizable:

Here is the male Io again, only without his wings spread.

By the way, before you decide to raise some Ios, be aware that the caterpillars sting.

They are literally a pain to raise. I did it once, but ended up releasing them after a few weeks because I was tired of getting stung.

The sensation is just like stinging nettle, only it lasts longer. They have a bad habit of dropping from their twigs when you move them around, which is necessary when changing out their food. Not only do you have to pick them up somehow, but I found out the hard way that those stinging hairs can penetrate denim.

Another show-stopper is the Royal Walnut moth:

Not only are they a gorgeous moth, but their caterpillars are the largest of any species in North America. They are so impressive they have their own name: the Hickory Horned Devil...

Citheronia regalis - HickoryHornedDevil-Simons.jpg
Despite their menacing appearance, they are harmless. The horns are all for show.

If you decide to try and raise some wild caterpillars, it's really important you identify your species! That will determine what type of plant you feed them.

Most moth caterpillars feed on trees and shrubs.

One good resource for identification and information on life history is the Butterflies and Moths of North America website.

We'll pick back up in a couple of weeks when my Cecropia eggs hatch, and then talk about how to raise the little guys! See you then!

Another male Luna moth


  1. Fascinating! I can't wait to read the next part of this series. :)

    1. They develop very quickly, so you won't have to wait long! They actually grow faster than rabbits! ;)

  2. That is amazing! I missed this post but I am so glad I found it. What beautiful creatures! I've always favored moths over butterflies for some reason- I want to try this so bad! Thank you! <3

    1. This was kind of a spur-of-the-moment post. I really wasn't expecting any more of the cocoons to hatch! They are fun to raise, though. :)

  3. That is fascinating! What beautiful moths. Thanks for sharing!

    Thanks for linking up with Green Thumb Thursday! I hope you'll stop back again this week!