Limnomysis benedeni ingestion rate in different prey

Understanding the diet preferences and food selection of invasive species
is crucial to better predict their impact on community structure and
ecosystem functioning. Limnomysis benedeni, a Ponto-Caspian
invasive mysid shrimp, is one of the most successful invaders in numerous
European river and lake ecosystems. While existing studies suggest
potentially strong trophic impact due to high predation pressure on native
plankton communities, little is known of its food selectivity between
phyto- and zooplankton, under different food concentrations. Here, we
therefore investigated the feeding selectivity
of L. benedeni on two commonly occurring prey organisms
in freshwaters, the small rotifer zooplankton Brachionus
calyciflorus together with the
microphytoplankton Cryptomonas sp. present in increasing
densities. Our results demonstrated a clear shift in food selection,
with L. benedeni switching
from B. calyciflorus to Cryptomonas sp. already
when the two prey species were provided in equal biomasses. Different
functional responses were observed for the two food types, indicating
somewhat different foraging mechanisms for each food type. These findings
provide experimental evidence on the feeding flexibility of invasive mysid
shrimps and potential implications for trophic interactions in invaded
ecosystems.