Impact of food concentration on diel vertical migration behaviour of Daphnia pulex under fish predation risk

Vertical migration of Daphnia represents the best-studied predator-avoidance behaviour known; yet the mechanisms underlying the choice to migrate require further investigation to understand the role of environmental context. To investigate the optimal habitat choice of Daphnia under fish predation pressure, first, we selected the individuals exhibiting strong migration behaviour. The animals collected from the hypolimnion during the daytime were significantly larger, being more conspicuous, and in turn performed stronger diel vertical migration (DVM) when exposed to fish cue. We called them strong migrants. Second, we provided the strong migrant D. pulex with food at high and intermediate (1 and 0.4 mg C l(-1), respectively) levels, which were well above the incipient limiting level and of high quality. They traded the benefits of staying in the warm water layer and moved down to the cold water in response to fish cue indicating fish predation. The availability of food allowed the animals to stay in the cold hypolimnion. However, at the low food level (0.1 mg C l(-1)), which is an additional constraint on fitness, Daphnia moved away from the cold hypolimnion. Poor food condition resulted in strong migrant Daphnia to cease migration and remain in the upper warmer water layer. Although temperature is known to be a more important cost factor of DVM than food, our results clearly show that this is only true as long as food is available. It becomes clear that food availability is controlling the direction of vertical positioning when daphnids experience a dilemma between optimising temperature and food condition while being exposed to fish cue. Then they overlook the predation risk. Thus, the optimal habitat choice of Daphnia appears to be a function of several variables including temperature, food levels and fish predation.


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Yuan, Guixiang; Fu, Hui; Zhang, Meihong; Lou, Qian; Dai, Taotao; Jeppesen, Erik (Springer Science and Business Media LLC, 2020-10-01)
The growth and reproduction of plants are highly size-dependent and markedly affected by light intensity.Vallisneria spinulosaS.Z.Yan is a common submersed macrophyte and is widely used in current lake restoration projects. The size of plants to be used to get optimal restoration results is not known, however, and may vary with water clarity. In this study, the effects of different plant sizes (large, medium and small, i.e. approximately 2.40 g, 1.01 g and 0.27 g per plant) on the growth and reproduction of...
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It has been argued that waterfowl and fish may threaten growth of submerged macrophytes, especially in spring during the early growth phase when plant biomass is low. A small reduction of biomass at that time might delay growth or decrease subsequent productivity. We investigated the impact of waterfowl and large fish on the spring growth of fennel pondweed (Potamogeton pectinatus L.) by employing an exclosure experiment in the macrophyte-dominated clear-water Lake Mogan, Turkey. Birds and large fish were e...
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While extensive knowledge exists on the relationship between nutrient loading and nutrient concentrations in lakes in the cold temperate region, few studies have been conducted in warm lakes, not least in warm arid lakes. This is unfortunate as a larger proportion of the world's lakes will be situated in arid climates in the future due to climate change and a larger proportion will suffer from a higher frequency of intensive drought. We conducted a comprehensive 11-13 year mass balance study in two intercon...
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Previous work on a set of small lakes, of varying depth, the meres of North West England, has shown that nitrogen availability controls the summer phytoplankton populations in the deeper ones (max depth > 3 m) and zooplankton grazing in shallow ones. The meres have generally high total phosphorus concentrations and this may be a natural phenomenon dependent on the local geochemistry. Some anthropogenic eutrophication has occurred, however, and from a chain of three meres, sewage effluent was diverted in 199...
Citation Formats
M. Beklioğlu, A. G. Gözen, and S. Önde, “Impact of food concentration on diel vertical migration behaviour of Daphnia pulex under fish predation risk,” HYDROBIOLOGIA, pp. 321–327, 2008, Accessed: 00, 2020. [Online]. Available: