アイテム詳細

要旨

Bomb-radiocarbon analysis of modern carbon has been applied in many fields of ecology. The method allows determining
the residence time of carbon in photosynthetic
products and thus all organic matter in ecosystems. The
atmospheric 14C signature will soon drop below the prebomb
level due to fixation of atmospheric carbon in terrestrial
and marine ecosystems and high rates of 14C-free
fossil fuel combustion. Hence, the time is running out for
bomb-radiocarbon application. Insect collections shelter
an immense quantity of specimens stored in alcohol. We
show how those specimens can be used for exploring the
trophic structure of food webs by comparing their isotopic
radiocarbon signature.
Arthropods are one the most diverse and numerous
groups of animals in many ecosystems. Their involvement
in the trophic structure of an ecosystem is often poorly understood,
but a good understanding of food web topology
is indispensable to investigate and model how structural
changes will affect ecosystem functionality (Dunne et al.,
2002). The first challenge in analyzing trophic structures
of arthropod communities lies in identifying the species
and then, in the very labor intensive methods, to study
their feeding habits. Recently isotopic methods have been
recognized as useful tools to describe the often nontransparent
linkages in the trophic levels of food webs. The
most recent development was the application bomb radiocarbon
by Hyodo et al. (2012) and Hyodo et al. (2015)
impressively showing how this method could be applied
to analyze the diet age of various invertebrates and even
vertebrates. By analyzing the diet age, the study showed
how intensively plant-based and detritus-based food webs
are connected and how long it takes for carbon to flow through the web from primary producers to the consumers.
Up to now applying bomb-radiocarbon in food
web studies is the rare exception; however this method has
become a standard tool in many other ecological studies
looking on residence time of assimilated carbon in biological
systems (e.g., Carbone et al., 2013; Muhr et al.,2013).