TY  - JOUR
A1  - Bukovinszky, Tibor
A1  - Helmsing, Nico R.
A1  - Grau, R. A.
A1  - Bakker, Elisabeth S.
A1  - Bezemer, T. Martijn
A1  - Vos, Matthijs
A1  - Uittenhout, H.
A1  - Verschoor, A. M.
T1  - A device to study the behavioral responses of zooplankton to food quality and quantity
JF  - Journal of insect behavior
N2  - In order to explore the behavioral mechanisms underlying aggregation of foragers on local resource patches, it is necessary to manipulate the location, quality and quantity of food patches. This requires careful control over the conditions in the foraging arena, which may be a challenging task in the case of aquatic resource-consumer systems, like that of freshwater zooplankton feeding on suspended algal cells. We present an experimental tool designed to aid behavioral ecologists in exploring the consequences of resource characteristics for zooplankton aggregation behavior and movement decisions under conditions where the boundaries and characteristics (quantity and quality) of food patches can be standardized. The aggregation behavior of Daphnia magna and D. galeata x hyalina was tested in relation to i) the presence or absence of food or ii) food quality, where algae of high or low nutrient (phosphorus) content were offered in distinct patches. Individuals of both Daphnia species chose tubes containing food patches and D. galeata x hyalina also showed a preference towards food patches of high nutrient content. We discuss how the described equipment complements other behavioral approaches providing a useful tool to understand animal foraging decisions in environments with heterogeneous resource distributions.
KW  - Foraging behavior
KW  - behavioral choice
KW  - food preference
KW  - Daphnia
KW  - flow-through vessel
Y1  - 2013
U6  - https://doi.org/10.1007/s10905-012-9366-0
SN  - 0892-7553
VL  - 26
IS  - 4
SP  - 453
EP  - 465
PB  - Springer
CY  - New York
ER  - 
TY  - JOUR
A1  - Hartwich, Melanie
A1  - Martin-Creuzburg, Dominik
A1  - Wacker, Alexander
T1  - Seasonal changes in the accumulation of polyunsaturated fatty acids in zooplankton
JF  - Journal of plankton research
N2  - In aquatic food webs, consumers, such as daphnids and copepods, differ regarding their accumulation of polyunsaturated fatty acids (PUFAs). We tested if the accumulation of PUFAs in a seston size fraction containing different consumers and in Daphnia as a separate consumer is subject to seasonal changes in a large deep lake due to changes in the dietary PUFA supply and specific demands of different consumers. We found that the accumulation of arachidonic acid (ARA) in Daphnia increased from early summer to late summer and autumn. However, ARA requirements of Daphnia appeared to be constant throughout the year, because the accumulation of ARA increased when the dietary ARA supply decreased. In the size fraction 140 m, we found an increased accumulation of docosahexaenoic acid (DHA) during late summer and autumn. These seasonal changes in DHA accumulation were linked to changes in the proportion of copepods in this size fraction, which may have increasingly accumulated DHA for active overwintering. We show that consumer-specific PUFA demands can result in seasonal changes in PUFA accumulation, which may influence the trophic transfer of PUFAs within the food web.
KW  - accumulation
KW  - Daphnia
KW  - copepods
KW  - ARA
KW  - DHA
Y1  - 2013
U6  - https://doi.org/10.1093/plankt/fbs078
SN  - 0142-7873
VL  - 35
IS  - 1
SP  - 121
EP  - 134
PB  - Oxford Univ. Press
CY  - Oxford
ER  -