However, detailed measurements of photosynthesis of carnivorous plants in response to prey or
nutrient additions—the primary measure of the first hypothesized benefit of carnivory—have generated more
equivocal results. Me´ndez and Karlsson (1999) reported no
significant increase in photosynthetic rates of Pinguicula
villosaL.,P. vulgarisL., orDrosera rotundifoliawhen they
were provided supplemental prey. Adamec (2008) found
that the photosynthetic rate of Aldrovanda vesiculosaincreased following prey additions, but that of Utricularia
australisdecreased following prey additions.