Question about cocoons at my lads' school

[PaulJBN]

As part of a nature project in my boys class, they have had delivered in the post, some caterpillars.

They come with their own tub of food and they stay in the tub until they turn into cocoons.

They are supposed to cling to the specially designed tub lid while in their cocoon form.

Now only one of them is still actually clinging to the roof of this tub, all the others having fallen to the bottom, where they are just lying there.

My question is: Will the cocoons lying on the floor be able to turn into butterflies ?

Don't they have to be hanging to be able to get out properly and complete their transformation ?

Once I get an answer, I can let my lads teacher know what you think, cos she was asking about it.

Thanks in advance.

[Pete Eeles]

Hi Paul,

Do you know what species this is? And by "cocoon", do you mean "chrysalis / pupa"?

Assuming that the pupae are not damaged, then I suspect they'll be OK where they are. However, you may end up with a few "cripples" that are unable to separate themselves from their pupal case. One option is to place the pupae back on the lid. At the end of most pupae (the "cremaster"), there is a set of small hooks. It is these that normally keep the pupa hanging in place, where they latch onto the silk pad spun by the larva. You may be able to "re-hook" the pupae back on these pads. Another option is to glue the pupae in place, but you have to be very careful not to get glue on anything other than the cremaster.

Cheers,

- Pete

[PaulJBN]

Yes, I meant chrysalis/pupa.

I'm not really up on all that kinda stuff.

I shall recommend that they are re-attached.

I was told they are going to be Tortoiseshells....not sure wether large or small though.

cheers