Collaborative Proposal: The Relation of Behavior of Copepod Juveniles to Potential Predation by Omnivorous Copepods

Skidaway Institute Of Oceanography, Savannah GA

Investigators

Abstract

During a planktonic copepod's life cycle the effects of predation can be particularly pronounced during the early naupliar stages. Among the major predators are omnivorous copepods. The processes leading to such predation have been evaluated but rarely demonstrated. These processes include fluid dynamics near both prey and predator, recognition of hydrodynamic signals by both, and the respective responses with either attack and/or escape, and the eventual outcome. The objective of this research project is to determine the various mechanisms that can lead to predation by omnivorous copepods on nauplii of different abundant species of planktonic copepods, and on an early copepod stage of one of those species. Our hypothesis is that predation rates are a function of a juvenile's motion and perception behavior, and the predator's perceptive and capture capabilities. We will determine these mechanisms by combining modeling studies with empirical observations. Published, unpublished, and newly obtained empirical results on copepod motion will be used to develop fluid dynamics models of free?swimming prey and predators as they approach and encounter each other. The same empirical data will be used to verify the modeling results. The modeling results will suggest new, additional empirical work. We feel that coupling modeling with empirical studies presents a promising opportunity to unravel the mechanisms leading to predation, in relation to the behavior of prey and predator. The ecological significance of the proposed studies is related to in situ mortality of copepod juveniles. Since this variable, mortality, is usually impossible to quantify in situ, our proposed research can be seen as an attempt to use results at small scales towards an understanding of a bigger picture i.e. the relation of behavior to mortality in the ocean. Intellectual Merit. The idea of combining this type of behavioral observations with the proposed hydrodynamic modeling is original. The modeling focuses on a self?propelled body, as compared to nonswimming particles used in previous studies. The empirical effort provides initial information for modeling, such as the various behaviors of the different prey and of the predator; and is later used to verify it. The expected results will provide insights on the comparative ability of early juveniles of different copepod species to minimize predation by co?occurring omnivorous species, including their own species. Broader Impact. We will provide with our empirical?modeling studies detailed information to undergraduate and graduate students at the Institute of Ecology and the School of Marine Sciences, University of Georgia, emphasizing the significance of interdisciplinary research in ecological studies. We will recruit at least 2 undergraduate students each year to cooperate closely with us. These undergraduate students will be trained for at least 3 months per year in copepod process studies, and advanced small?scale modeling of fluid dynamics. The significance of the proposed research is to develop a general understanding of the probability of predation on early copepod juveniles by adult omnivorous copepods.