I would not be so sure, my friend. At least 2 species are common in our areas[FONT="](Ireland, Britain) [/FONT] : Hedera helix( ditto), and Hedera hibernica. And if you have a look at pictures provided for different species in the link I gave, you realy need to be an expert in order to distinguish ivy species .
I.e. Hedera rhombea (or Japanese ivy)
http://en.wikipedia.org/wiki/Hedera_rhombea [FONT="]is very similar to helix.[/FONT]
“The island Hedera of Macaronesia in the eastern Atlantic, northern African Hedera and European Hedera are closely related species. Until recently it was thought there was a single species (Hedera helix), but recent studies have shown that there are several species that differ mainly by microscopic details of the hairiness of the buds.”
http://en.wikipedia.org/wiki/Hedera_canariensis
I`m sure it affects nectar density, but in doubt whether may it affect ratios of sugars , as it`s mostly genes programmed factors AFAIK.