Yet another unidentified caterpillar - knotgrass?

18ck · #1 (**permalink**) 18-09-2010, 05:14 PM

Found while out exploring with my daughter. we think it's a knotgrass caterpillar although it seems to have slightly less red on the body and slightly more orangey hair than the pictures i've found. it's not a bad match though. Sorry for the terrible pic... am i on the right lines or are there other candidates?

The leaves in the jar are the ones it was munching when we found it.
We're mainly trying to figure out how to look after it - e.g., is it ok in this size of jar? should we change the leaves or leave well alone? does it need water to drink? what does it like to pupate on? so if anyone can point me to that info too we'd be very grateful!

GuyF · #2 (**permalink**) 19-09-2010, 02:11 PM

Hi and welcome to the site!
You're correct with your identification, it's a Knot Grass.
Hopefully someone with more experience of rearing larvae will be able to give you some advice soon, but for the moment I will have a go at answering your questions!
1. It should be fine in that jar as long as you don't put it anywhere too hot or sunny, then there may be a risk of it overheating!
2. You should try and regularly replace the leaves that it's feeding on with fresh ones. From the photo it looks like it's feeding on a species of Plantain e.g. Ribwort Plantain, this tends to be quite common so hopefully you'll be able to find some more of the same.
3. It won't need water to drink, but people often suggest providing some moisture by spraying a very light mist on the foodplant or jar every few days, too much water can cause problems though!
4. Knot Grass caterpillars pupate in leaf litter apparently. This caterpillar looks like it's fully grown so it probably won't be too long before it decides to pupate, if you provide a good thick layer of leaf litter in the bottom of the jar that should keep it happy!
After that it can be left for the winter in a cool, sheltered place, and at some point next spring you should see the adult moth.
Good luck!
Guy

18ck · #3 (**permalink**) 19-09-2010, 08:43 PM

Thanks GuyF - I'm very impressed you managed to identify the leaves, but yes, you're right - we hunted some up and sure enough these ones had the sort of flowery seedy bits (to use the technical term) which even i was able to identify! However, it seems as though once they wilt a bit the caterpillar (now named sweetpea) loses interest in the leaves and just sits there until new ones are brought, so i guess we have a daily chore now of topping them up until she is ready for the big sleep.
She is now munching away happily. She's a she, and if my daughter could find a pink dress small enough she'd have put it on her...
re. pupation, presumably old, manky, wilted plantain leaves aren't classed as leaf litter though are they? i guess dried-out leaves, maybe some little bits of twig?

18ck · #4 (**permalink**) 24-09-2010, 04:55 AM

I'm getting a bit concerned about sweet-pea now. She didn't eat any of the leaf i brought her yesterday just tore round her jar at a greyhound's pace. i take this as indicating she was looking for a place to pupate so if anyone has any more advice on what that leaf litter should consist of i'd love to hear from you!

18ck · #5 (**permalink**) 01-10-2010, 10:57 AM

Well at the risk of seeming like a man having a conversation with himself... we put in about 8 dried-out tree leaves of various textures and a small twig, with some fresh plantain leaves in case she was still peckish. She didn't come out from under at all and after a week or so we wondered if she had joined the choir invisible but after some careful investigation with the chopsticks she does indeed seem to have made herself a cosy cocoon in between two leaves. i could even feel her wriggling. So we've put everything back and we're looking forward now to the arrival of a moth in... April???