Wild teasel leaf reservoirs

[Hedera]

I am growing a wild teasel near my pond and noticed the water contained at the leaf axils after it rained. Is there a reason for this, e.g trapping or attracting insects or absorbing the water?

[Johnny Redgate]

I wish I knew. I, too, have wondered whether the plant gains any benefit from insects trapped in the water. Perhaps we could design an experiment to feed a group of plants insects and compare it with an unfed group?

[Richard Baber]

It's an interesting question. The teasels in my garden always end up with drowned insects in their leaf bases and the suggestion has certainly been made that teasels could be carnivorous plants. I only know of one paper looking into this, which suggests that teasels prevented from catching invertebrates have noticably smaller seeds:

Carnivory in the Teasel Dipsacus fullonum ? The Effect of Experimental Feeding on Growth and Seed Set

Richard

[Johnny Redgate]

Brilliant Richard, thanks for the link. I'll have a look at that tonight.

[Hedera]

Thanks for that Richard. I've just had a look and there are some tiny black blight in one axil! Can't think why I'd never noticed this before in my lifetime.

[Richard Baber]

I've just had a quick nose around the 3 teasels in my garden. Many of the pools have dried out, as the axils have torn, but in those remaining there are many aphids, one harlequin larva, one fly and one wasp. Whatever the reason, they are effective traps.

Richard

[Hedera]

Very interesting article on the research. They mention at the end "how were the insects ingested", but they never mentioned testing the content of the water: whether the plant exudes toxins etc. Drowning seems unlikely for, say, a wasp?

[Meta menardi]

There is a large bank of teasels near me, I have always just taken it as a "known" that they derive something from the reservoirs, it is very interesting to see some evidence.

[Johnny Redgate]

I've just had a quick look at the paper. Very interesting. The authors thought it needed duplicating. I see a big WAB-based experiment

[Richard Baber]

Count me in.

Richard