>mainly P. vulgaris with some P. alpina, is that NOT A SINGLE INSECT was
> glued on the leafs. Leafs were in good conditions, and insects were all
>around, but
>I have not found a single captured prey.
I also have seen many Pinguicula sites with no or almost no insect prey
glued on the leaves, while some dozen meters apart the rosettes of the same
species are full of sciarid and similar flies, smaller ants and other
insects. Some insects seem to be more picky about microclimate and other
habitat conditions than the Pings. In species which usually do not grow in
pure Sphagnum but in more nutritious substrate (e.g P. alpina, balcanica,
corsica, grandiflora, leptoceras, vulgaris) I could not observe a
conspicuous difference of leaf size, vigor, number of flowers, hibernaculum
size between specimens with and without heterotrophical support. However
species growing in Sphagnum bogs (P. variegata, villosa) or petrophilous
species (e.g. P. crystallina/hirtiflora, longifolia, vallisneriifolia) seem
really to grow somewhat more vigorously and forming larger winter buds if
thrilled by some protein (nitrogen) supply.
Juerg
___________________________________________________
Juerg Steiger, Institut fuer Aus-, Weiter- und Fortbildung IAWF
University of Bern, Inselspital 37a, CH-3010 Bern, Switzerland
Office: +41 31 632 9887 Fax: +41 31 632 9871