Prey capture by the non-native carnivorous pitcher plant Sarracenia
purpurea across sites in the Britain and Ireland.
Abstract
• The carnivorous pitcher plant Sarracenia purpurea is native to North
America, but has been introduced into Europe, where it is now
widespread. We have little understanding of how this species functions
in its non-native range. Such understanding will provide insight into S.
purpurea ecology and support its use as a model system for investigating
food webs. We measured pitcher morphology and prey capture by S.
purpurea in Britain and Ireland. • Pitchers were removed from different
plants at each of six bogs covering the species rage in the UK and
Ireland (n = 10 pitchers per site). For each pitcher we counted and
identified every prey item and took measurements of morphology. We also
compiled prey capture data for existing studies in Europe and North
America. • Prey capture characteristics varied between sites in the UK
and Ireland. The amount of prey captured varied 2-fold between sites and
was partially explained by differences in pitcher size; larger pitchers
caught more prey. The primary prey was Formicidae, Diptera and
Coleoptera. At the rank of order, prey composition varied between bogs,
some contained mainly Formicidae, some mainly Diptera and some a mix.
Plants were more specialised in prey capture at some bogs compared to
others. There was no overall difference in prey capture (composition or
degree of specialism) at the rank of order between plants in Europe
compared to those in North America. At the rank of species, prey capture
varied between populations even within the same order. • This study
demonstrates a large amount of variability between sites in prey capture
characteristics. This may reflect different site characteristics and/or
plant strategies, will likely impact plant function, and may impact on
the inquiline community. In terms of prey capture at the rank of order
S. purpurea functions identically in its non-native range. This supports
its use as a natural experiment for understanding food webs