50%: when feeding potential hosts with Nitrogen 20-30% %/within few hours
||Parasitic plant Cuscuta spp. (dodder)
||Trewavas A. The foundations of plant intelligence. Interface Focus. 2017 Jun 6 7(3):20160098. doi: 10.1098/rsfs.2016.0098. p.9 right column top paragraphPubMed ID28479977
|| Kelly CK. 1990 Plant foraging: a marginal value model and coiling response in Cuscuta subinclusa. Ecology 71, 1916–1925 link  Kelly CK. 1992 Resource choice in Cuscuta europaea. Proc. Natl Acad. Sci. USA 89, 12194–12197 PubMed ID11607344
||Primary source  abstract: "Stems of the parasitic plant Cuscuta subinclusa (Convolvulaceae) discriminate among host species and invest in resource acquisition (coil around the stem of a host plant) relative to host quality in a way predicted by a marginal value model of resource use." Primary source  abstract: "Individual stems with growing tips of dodder (Cuscuta europaea) were transplanted onto host plants (hawthorn) of varying nutritional status."
||P.9 right column top paragraph: "Kelly [primary sources] offered numerous suitable hosts to dodder by tying them together and found a rejection rate of 50% within a few hours, indicated by the parasite branch growing away. The assessment period is thus completed in this short time and since contact is only surface in character, assessment is probably made of the volatile chemical signature of the host. Dodder is using taste like Lymnea and changing search strategy when the source is not satisfactory. The future assessment of host potential is made in these few earliest of hours. By feeding potential hosts with N, rejection can be reduced to 20–30%, suggesting additional N modifies host chemistry in terms of volatile organic compound synthesis and food suitability. The parasite can make a quantitative assessment of the future resource return."