CS39B Zooplankton - Community Dynamics
Date: Wednesday, June 12, 2002
Time: 11:30:00 AM
Location: Sidney
 
RiessenHP, SUNY College at Buffalo, Buffalo, USA, riessehp@buffalostate.edu
 
RE-EVALUATION OF INVERTEBRATE PREDATION IN ZOOPLANKTON COMMUNITIES: DOES SIZE REALLY MATTER?
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The generalization that invertebrate predators in plankton communities strongly select small zooplankton prey (primarily < 1 mm in body length) has been a cornerstone of zooplankton ecology for nearly 30 years. However, close examination of the diverse feeding behaviors found among the array of invertebrate planktivores present in lakes and ponds reveals that this widely accepted view is limited in scope and often untrue. I re-examine invertebrate predation on zooplankton by classifying both predators and prey into functional groups based on their interactions with one another. Predators are categorized according to the particular mechanism they use to handle and ingest prey (engulfing, shredding, or piercing-sucking), size of the feeding apparatus, and their relative ability to detect and attack prey before being detected themselves (continuum from ambush predators to "quiet" cruising predators to "noisy" cruising predators). Prey are arranged in a 3-dimensional "vulnerability space" according to their size, development of morphological defenses, and effectiveness of evasion behavior. This integrated approach to predator-prey interactions provides a much more realistic picture of invertebrate predation in zooplankton communities than one based solely on prey size.