Tag Archives: metamorphosis

Very hungry caterpillars

The unschooling diaries: week twenty-five

After the success of our tadpole project, I’ve been on the lookout for another opportunity to explore metamorphosis in action. A couple of weeks ago one appeared, in the shape of several very hungry caterpillars eating their way through our lettuces.

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We picked out two, and created a little habitat for them in the fishtank, complete with the remains of one of the lettuces they had been munching so that they could continue to prepare for their transformation.

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They were already pretty big when we found them, and it wasn’t long at all before they each settled into a crevice in their new home and began to spin a web of silk around themselves.

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This was fascinating to watch, as was the way their bright green bodies slowly went brown and hard as they pupated.

Whilst we waited for them to hatch, we read up about the process – Usbourne Beginners ‘Caterpillars and Butterflies’ had lots of interesting facts, and of course we re-read Eric Carle’s classic. I also did a bit of googling to try to find out what sort of butterflies we might expect, and discovered that actually the silk cocoons suggested that we were more likely going to be welcoming moths.

And indeed about ten days later first one then the other broke out and spread their wings.

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We watched them for a couple more days, and when we were sure that their wings were strong enough Arthur reluctantly agreed to let them go.

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Once they had flown away, he was keen to have a closer look at the empty cocoons. He felt the sticky silk, and prodded at the shell of the pupa within.

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And after that, whilst I attempted to tidy up our overgrown veg patch, he even washed out the tank, ready for his next pets.

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As it happened, he didn’t have to wait very long. I had a feeling that the latticed spinach and calendula might be hiding some more little creatures and, in fact, it was teeming with them.

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It made for some very interesting conversation, around how these bugs are interesting to watch and study but are also pests, especially when they’re competing for our vegetables! We transferred some of the caterpillars we found to another part of the garden, but because they looked different to the first ones we’d found we decided to keep a few back so we could observe the metamorphosis process again and see if we noticed any changes.

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After this lot I think we’ll be done though, at least till next year…

Anyone have any ideas how we can make the remains of our crops slightly less attractive to the very hungry caterpillars? After all, it would be quite nice to be able to enjoy some of our vegetables too!

Project metamorphosis

The unschooling diaries: week seventeen

Just over a month ago, we were in my parents garden when we spotted clusters of tadpoles in their pond. I mentioned how cool it would be to have some for Arthur to watch grow at home, and a little while later my brother appeared with a jar containing four little tadpoles and a healthy dose of pondweed. Thus began our science project for the past few weeks – one which fascinated me at least as much as it did Arthur!

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First step was to prepare a suitable habitat. A bit of googling suggested a fairly shallow container with space for the tadpoles to swim and also to hide, and rocks for them to crawl up on once they developed legs. I decided that the fish kettle was the closest thing we had to a tank, and Arthur helped me collect a selection of stones to help make it a bit more homely.

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He was pretty chuffed with how it turned out, and loved to watch the tadpoles swimming around and getting used to their new home.

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In fact each morning we both gravitated towards the tadpoles to check how they were getting on: Arthur curious to see what pets were up to, me desperately hoping that I would have more success with amphibians than I do with house plants.

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They seem to get on ok, but after the first week or so it was clear that we were going to have to clean them. My mum brought over a fresh supply of pond water, and Arthur helped me clear out the worst of the muck using a baster (thank you google again) which worked surprisingly well!

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All of these online investigations, though, were making me doubt the wisdom of the receptacle I’d chosen to contain them. Apparently you shouldn’t use anything made of metal (though I didn’t manage to find a reason why) and, more compellingly, a lid would come in very handy for stopping seagulls from sourcing an easy lunch when they were out on the deck and stopping the little froglets themselves from climbing (or jumping) out when metamorphosis kicked in.

So I found a cheap and cheerful fishtank, and Arthur helped me transfer them over (with another dose of pond water for good measure).

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The transparent tank had the advantage of making it much easier to see what was going on, though I’m not sure how much the tadpoles liked being on display 24/7…

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Under our constant surveillance it did feel, for ages, as if nothing much was happening. The tadpoles were definitely getting bigger: we experimented with feeding them finely chopped, frozen lettuce, though to be honest I think they preferred the pond weed. We read some books, so we knew what was coming: Osbourne Beginner’s Tadpoles and Frogs was predictably good, as was the slightly macabre Tadpole’s Promise.

But every morning when we checked they were still just tadpoles. Until one day things began to change… And once the metamorphosis had started they seemed increasingly frog-like (and increasingly well camouflaged) every time we looked.

One of the things that I thought was particularly interesting (and particularly apt, seeing as we were right in the middle of our anti-SATs campaign), was the different pace at which the tadpoles developed. Even though they had all looked identical at the start, their metamorphosis progressed at quite different rates.

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They all got there in the end though, and one morning we came down to find four tiny but perfectly formed frogs witting on top of the rocks.

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It was at this point that I started to get really worried about keeping them alive – whilst the tadpoles can survive on pond weed, frogs are carnivorous and need live insects to sustain them. There were a fair few bugs in the pond water, and we increasingly left the tank outside to entice others into their lair, but still it was clear that we were going to have to return them to their habitat sooner rather than later.

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And so, on a suitably grey and rainy day, we took our little frogs in their tank back to my parents’ pond, and released them back into the wild.

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It was genuinely a little bit sad to be saying goodbye to them (though I was secretly proud as well that we still had four). Arthur was incredibly careful and gentle as he helped me transfer them one by one from tank to pond, and once the frogs had got over their initial bewilderment at how big their world had become they hopped happily away.

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We did have one little guy who seemed less sure about the transition, but once we’d persuaded him to check out the world on the other side of the tank he seemed to agree it was preferable.

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All in all this has been a wonderful learning opportunity for Arthur (and me). I’m already keen to do it all again next year, and in the meantime am thinking about what our next living science project might involve.

Arthur’s asking for a dog, but I’m thinking worms might be more likely…