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Raising Cabbage White Caterpillars

July 4, 2014

Two weeks ago I discovered some visitors in my garden who weren’t invited but weren’t wholly unwelcome either.

I knew I couldn’t leave the tiny caterpillars in my flower pots because they would devour and destroy my plants so instead of relocating them to allow nature to take its course elsewhere I decided to raise them in the house.

Below I have detailed the whole experience of raising the tiny caterpillars with a lot of photos and even a few videos. I’ll make another post in a couple of weeks when (if) the butterflies emerge following their metamorphosis. 

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The first butterfly we saw investigating the planter when we happened to be out playing with the paddling pool in the garden.

This story starts with the two giant half barrel planters I got for Christmas. I’ve always wanted recycled whiskey barrel planters because I just love the rustic look of them in a garden and lucky for me, my mother-in-law is an amazing gift picker.

Once spring finally sprung we filled them with soil and I planted seeds, eagerly anticipating what they would look like once they filled in. Then to my complete lack of surprise the neighbor’s cat decided the barrels were her new litter boxes, which was a change from her usual act of going right in the middle of the yard while watching me through the window.

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This is what happens when you dump approximately 6 random packets of seeds into a large barrel planter

Then since I had lost all of my sprouts I panic planted a PILE of seeds of plants I’ve never grown before in the planters and as a result they sort of exploded with life. About 8 of the seeds I planted between the two planters were Nasturtiums which took in a big way.

I didn’t realize it at the time but apparently cabbage white caterpillars adore Nasturtium leaves and one day before there were any flowers my husband and I spotted a cabbage white butterfly showing a great deal of interest in the planters.

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This is how big they were when I found them

Shortly afterward we found a LOT of caterpillars in multiple deposits. I removed 23 of about 100 and put them in a bug observation jar for my daughter.

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Our 2 year old observing her little pets in the bug jar she got for her birthday from her great grandparents. Because every child NEEDS a bug jar :)

They were easy to identify despite their tiny size with some help from an amazing UK website dedicated to butterflies . 

To introduce them to our daughter I showed her websites with photos of the caterpillars.

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After she had been at it for about 3 minutes I brought out the jar and I wish I’d had a camera ready because in that moment when she put two and two together her face lit up in a way I can’t even describe.

I am not ashamed to admit that I was so proud I welled up a little.

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Here I underestimated how much they would be eating overnight, which never happened again.

The caterpillars were ravenous and went through about 1-2 and then 2-3 leaves a day for 2 weeks. This actually was good for my plants because the Nasturtium leaves were shading all of the plants trying to grow in the middle of the planter and feeding the caterpillars was a good excuse for thinning them out.

About every 2 days the caterpillars would crawl up to the lid of the container and molt.

I observed them whenever I could because, you may find this difficult to believe (sarcasm) but ever since I was old enough to put a bug in a jar I have found this sort of stuff absolutely fascinating.

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These are all lined up to molt and you can see one skin in the photo. The molted caterpillar is the one with the white face.

Everywhere they went they spun silk. The entire interior surface of the container where they lived was coated in a thin layer of silk and when I damaged parts of it they would actually target those areas for repair.

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I thought this photo best illustrated how oddly shiny they get before they actually shed their skins. It’s also a pretty good photo of the shed skins from the others. Note the mesh on the glass from the carpet of silk!

Watching them molt was interesting as well because they would sort of fix their bum to a surface away from the food and then go completely rigid for several hours. Before they actually came out of their skin they’d also start to look sort of taught and shiny as opposed to pudgy and fuzzy. I only witnessed them coming out of their skins a couple of times in the entire 2 weeks before they pupated because when they finally came out, it happened fast and then they speed away to chow down on some leaves.

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From the underside

Besides being adorable eating machines they are very curious little beasties. I really enjoyed observing them just crawling around when they were larger and their features were easier to make out.

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Adorableness

Of course everything that went into the 23 little guys came out again in the form of tiny green pellets so I also cleaned out the container about every 3 days just to remove the poo, the skins and the wilted abandoned leaf skeletons.

I used a soft paintbrush to handle any caterpillars that I needed to physically move because this was the most gentle way that I could think of to do it. Sometimes it took a lot of coaxing to get them onto the paintbrush so cleaning out the container could sometimes take a while.
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I brought the jar out for my daughter to look at every day for as long as her extremely limited attention span would allow (about a minute). On a few occasions I allowed her to pet one that was stuck to a leaf while I was cleaning out the poo which she was very excited about. I didn’t handle them at all with my hands and neither did she. I don’t actually know if they’re biters but I didn’t want to find out the hard way.

I especially love watching them eat and  looking at their sweet little feet and bellies from the underside.

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They more or less grew at the same rate. Some were noticeably fatter than others but they were generally the same length except for one runt who never seemed to grow no matter how often he molted. The fact that some were getting so fat probably should have served as a warning to me if I knew then what I now know about parasitic wasps. (keep reading)

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Here is a good perspective photo of the runt.

Anyhoo… they ate and ate and grew and grew and GREW and thankfully I’d ordered a butterfly habitat thingy for them from amazon shortly after I’d decided that I was keeping them because it arrived in the mail just in time.


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Funnily enough, this particular habitat was marketed with cabbage white (large white) butterflies in mind which I hadn’t even noticed when I made my purchase. It was in my price range and it was the right size so I was happy, it even came with an order form for mail order caterpillars.

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The habitat is sort of just a pop up tent with clear plastic on two sides as well as the top, mesh on the other two sides and nylon on the bottom. There are handles and a zipper at the top for loading in the caterpillars as well as their food.

I put some sticks in there because I wasn’t sure if the caterpillars might like them for pupating on. As it turns out they loved them for exploring but not a one tried to pupate on a stick.

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Runty again

The transparent sides and lid make for very clear observation. I’m 100% happy with the product, especially since I can see it lasting us for years.

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Tummy tummy

 

In the video above I recorded the caterpillars doing adorable caterpillar stuff the day before they started to pupate/explode.

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As I was pretty sure that the caterpillars had all just completed their last molt I took some final photos of them with a penny for perspective. I read that they were supposed to get to 5cm long before they pupated but I’m pretty sure they were really about 4cm.

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I figured that the caterpillars had entered their first stages of pupation when I noticed one had fixed its bum to a spot, spun a girdle and assumed a really odd posture.

Several  others had gone up to the top and sides of their habitat and just froze as if they were going to molt. Then a few began to move in a really repetitive way.

I watched one specifically all night (while also watching a couple of films) as it went back and forth on the same spot over and over for about an hour laying down a thick bed of silk. It then made a concentrated spot of silk on the bed of silk that looked like a white dot. It then proceeded to attach its butt to the spot and rested.

When it began to move again it was spinning its girdle which is the harness that the caterpillar spins around its waist. The concentration of the silk used for the girdle creates another two distinct white spots on either side of the middle of the catterpillar where they’re attached to the surface which happened to be clear plastic.  I was fairly curious to see how this was actually done since the mechanics of it seemed a bit awkward so when it happened I took a short video. (below)

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Note two girdle spots, a butt spot and the odd posture.

 

Once the girdle was spun  the caterpillar rested and assumed that weird posture I’d seen in the other one (see photo above) where it drew its front legs in and hunched up its head appearing to shorten its whole body. After this happened it was bedtime so I couldn’t watch them any longer. The following morning, the unexpected happened.

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The first thing that I did when I came downstairs was I checked on the caterpillars to see how many of them had pupated overnight… what I found was most of them either sitting on a tidy pile of silk cocoons or literally bursting out the sides with wriggling wasp larvae.

I knew it was a possibility that this could happen but they were SO tiny when I found them I didn’t really think that a wasp had time to lay eggs inside.

Clearly I was mistaken.

I was especially perplexed when the caterpillars who had just had dozens of larvae burst out of their skin started to move. I’d assumed they were dead after such a traumatic event, but alas they were only paralyzed.

So it was time to visit Google where I learned all about what was happening from a very informative, short National Geographic video on YouTube.

I took my own videos of what was happening but, of course NG did it better. As it turns out the larvae paralyze the caterpillars while they exit and then they crawl under and make themselves little coccoons. Once they’re nicely cocooned the paralization wears off and the brainwashed caterpillar starts spinning more silk over it’s little parasite brood to keep them nice and safe. Then the wounded caterpillar sits on top of them to defend them until it dies of starvation. Sad but true. It’s grotesque… but that’s nature. (watch the NG video!!!)

So after I recovered from the disappointment of losing my caterpillars I noticed that the ones who had spun girdles the night before hadn’t burst and there were 8 of them in the pupa pose so I figured they must not have been infected considering the fact that they went along their normal life cycle up to that point.

 

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I don’t kill things unless it’s absolutely necessary but I also couldn’t have a hundred wasps in my house so I figured that I would compromise and remove all of the caterpillars who had exploded, along with their wasp larvae and I’d put them back in the garden to let nature take its course. Removing them from the habitat was really easy since the silk which had been woven EVERYWHERE just came away in a sheet. I used a butter knife to wedge between the larvae and the habitat and it worked very well to gently pry them off.

Along with the caterpillars I removed I also included the few who hadn’t burst or started to pupate just to be safe.

That is how I’ve ended up with 8 pupated caterpillars out of the 23 I’d raised.

Here is the video that I took of the caterpillars after I removed them. Some of the brainwashed caterpillars got separated from their larvae and just started weaving silk over the first brood they found. You can see in the video as well as in the photo directly above the video that there are three caterpillars tending one little pod of wasp larvae. The caterpillars that aren’t moving hadn’t regained their ability to move yet but they were quite alive.

 

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You can very clearly see the girdle at work here

The next day when I came downstairs I was very happy to find 8 of these ^^. I half expected more wasp cocoons but what I found was that they’d all progressed in their pupation and shed their skin as the pupa took it’s bizarre spiky shape. Each one had a little skin nugget hanging from the bottom with a little face on it which was slightly disturbing. I was surprised at how small the pupa are compared to the length of the caterpillars when they make them. It’s really scrunched up.

So at the time I’m writing this, all 8 are still looking perfectly healthy. The vibrant green has faded a bit and every once in a while the whole thing will twitch. I’m hopeful that they’ll emerge as butterflies and then we’ll release them.

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There were actually two separate batches on the leaf I found. The one in this photo is of the older/larger batch, the others were actually half that size and the penny is right up against it so there is no perspective gap. They’re freaking tiny.

Yesterday I also found another massive batch of caterpillars on my Nasturtium and they were even smaller than the batch that I’d raised.

*Updates* Click HERE if you’d like to read about our butterflies.

Click HERE if you’d like to see some photos I managed to get of a parasitic wasp with some sawfly larvae.

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From → Scotland

4 Comments
  1. pebbles4christ permalink

    Thank you for your wonderfully informative blogpost! I’ve just rescued a whole lot (30+) of Cabbage White Caterpillars from my mother-in-law’s cabbages & wasn’t certain how to take care of them.

Trackbacks & Pingbacks

  1. Sawfly Larvae And A Parasitic Wasp | StuwahaCreations
  2. Butterfly World – Edinburgh | StuwahaCreations
  3. Cabbage White Butterflies | StuwahaCreations

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