Food-dependent aggregation and mobility of the water fleas Ceriodaphnia dubia and Daphnia pulex

1994 ◽  
Vol 72 (7) ◽  
pp. 1217-1226 ◽  
Author(s):  
K. M. Cuddington ◽  
E. McCauley
Keyword(s):  
Swimming Speed ◽  
Daphnia Pulex ◽  
Food Concentration ◽  
Ceriodaphnia Dubia ◽  
General Interest ◽  
High Food ◽  
Predator Prey ◽  
Individual Mobility ◽  
Flow Through ◽  
Filtering Rates

In this paper, we show that two freshwater cladoceran zooplankters (Ceriodaphnia dubia and Daphnia pulex) differ in swimming speed and ability to locate local regions of high food concentration in a flow-through circular chamber. This comparison is of general interest, since models of spatially structured predator–prey dynamics have predicted that differences in individual mobility and foraging behaviour may affect spatial distributions and, consequently, population dynamics. Daphnia pulex was more mobile than C. dubia, and also located the high end of a food gradient while C. dubia did not. It seems likely that the mechanisms used by D. pulex to locate these regions are related to ingestion and (or) filtering rates. It was hypothesized that individuals reduce their swimming speed in order to linger in regions of high food concentration. Differences in mobility and behaviour between C. dubia and D. pulex were used to generate hypotheses about the distribution and stability of their respective populations. Specifically, it was predicted that C. dubia populations would have a more aggregated and, consequently, a more stable population in smaller environments than D. pulex.

scholarly journals Inducible morphological defense in Daphnia pulex: food quantity effects revised

2020 ◽  
Author(s):  
Sandra Klintworth ◽  
Eric von Elert
Keyword(s):  
Chemical Cues ◽  
Daphnia Pulex ◽  
Food Concentration ◽  
Bacterial Degradation ◽  
Inducible Defenses ◽  
Chemical Cue ◽  
High Food ◽  
Food Quantity ◽  
Morphological Defense ◽  
Food Concentrations

Abstract In aquatic systems, organisms largely rely on chemical cues to perceive information about the presence of predators or prey. Daphnia recognize the presence of the predatory larvae of Chaoborus via a chemical cue, emitted by the larvae, a so-called kairomone. Upon recognition, neckteeth, an alteration of the carapace, are induced in Daphnia that reduce predation rates of Chaoborus. Neckteeth induction was often reported to entail costs. In a previous study, food quantity affected the level of neckteeth induction, with stronger neckteeth induction at low food concentrations and weak induction at high food concentrations. However, reducing neckteeth induction at high food quantities seems to be maladaptive and not in accordance with the concept that inducible defenses are associated with costs. Here, we hypothesized that weaker neckteeth induction at high food concentrations is caused by increased bacterial degradation of the kairomone. More specifically, we assume that higher algal food concentration is associated with higher bacterial abundances, which degrade the kairomone during the experiment. We tested our hypothesis by treating food algae with antibiotics before providing them as food to Daphnia. Antibiotics reduced bacterial abundances at high and low food concentrations. Reduced bacterial abundances at high food concentrations led to the same level of neckteeth induction as at low food concentrations. A linear regression revealed a significant correlation of neckteeth induction to bacterial abundances. We therefore conclude that differences in neckteeth induction at different food concentrations are not caused by the food quantity effects but by differences in bacterial degradation of the kairomone.

scholarly journals Predator-prey nutrient competition undermines predator coexistence

2019 ◽  
Author(s):  
Toni Klauschies ◽  
Ursula Gaedke
Keyword(s):  
Nutrient Limitation ◽  
Uptake Rate ◽  
Species Coexistence ◽  
Logistic Growth ◽  
Nutrient Competition ◽  
Functional Responses ◽  
Predator Prey ◽  
Natural Systems ◽  
Prey System ◽  
Flow Through

AbstractContemporary theory of predator coexistence through relative non-linearity in their functional responses strongly relies on the Rosenzweig-MacArthur equations (1963) in which the (autotrophic) prey exhibits logistic growth in the absence of the predators. This implies that the prey is limited by a resource which availability is independent of the predators. This assumption does not hold under nutrient limitation where both prey and predators bind resources such as nitrogen or phosphorus in their biomass. Furthermore, the prey’s resource uptake-rate is assumed to be linear and the predator-prey system is considered to be closed. All these assumptions are unrealistic for many natural systems. Here, we show that predator coexistence on a single prey is strongly hampered when the prey and predators indirectly compete for the limiting resource in a flow-through system. In contrast, a non-linear resource uptake rate of the prey slightly promotes predator coexistence. Our study highlights that predator coexistence does not only depend on differences in the curvature of their functional responses but also on the type of resource constraining the growth of their prey. This has far-reaching consequences for the relative importance of fluctuation-dependent and -independent mechanisms of species coexistence in natural systems where autotrophs experience light or nutrient limitation.

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

Hydrobiologia ◽  
2008 ◽  
Vol 614 (1) ◽  
pp. 321-327 ◽  
Author(s):  
Meryem Beklioglu ◽  
Ayse Gul Gozen ◽  
Feriha Yıldırım ◽  
Pelin Zorlu ◽  
Sertac Onde
Keyword(s):  
Predation Risk ◽  
Vertical Migration ◽  
Diel Vertical Migration ◽  
Daphnia Pulex ◽  
Fish Predation ◽  
Food Concentration ◽  
Migration Behaviour

scholarly journals A Tale of Two Metrics: The EPA Risk Quotient Approach versus the Delay in Population Growth Index for Determination of Pesticide Risk to Aquatic Species

2021 ◽  
Author(s):  
John D. Stark ◽  
John E. Banks
Keyword(s):  
Population Growth ◽  
Daphnia Pulex ◽  
Growth Index ◽  
Ceriodaphnia Dubia ◽  
Aquatic Species ◽  
Risk Quotient ◽  
Cladoceran Species ◽  
Generation Times ◽  
Species Being

Abstract The risk that two closely related insecticides, spinetoram and spinosad, posed to three Cladoceran species, Ceriodaphnia dubia, Daphnia pulex, and D. magna was determined using two approaches, the USEPA Risk Quotient method and the Delay in Population Growth Index (DPGI). Results of the RQ method showed that spinetoram posed a risk to all three species, but spinosad posed a risk only to C. dubia. The DPGI analysis showed that exposure to spinetoram resulted in populations of all three species being delayed > 3 generation times. Exposure to the LC50 and the lower 95% CL resulted in delayed populations while exposure to the upper 95% CL concentration of spinetoram resulted in no recovery of any of the three species over the course of the modeling exercise (88 d). Exposure to the lower and upper 95% Cl and the LC50 of spinosad resulted in C. dubia populations being delayed > 3 generations. D. pulex populations were not negatively affected after exposure to spinosad. D. magna populations were delayed > 3 generations, but only after exposure to the upper 95% Cl of spinosad. These results illustrate that although the EPA risk quotient method indicated that spinetoram posed a risk to all three species and that spinosad only posed a risk to C. dubia, the DPGI showed that D. magna would be negatively affected by spinosad and none of the three species would recover after exposure to the upper 95% CL of spinetoram. Because the DPGI uses the 95% Cl as well as the LC50 in its calculation and produces a measure of population growth and recovery or lack thereof, it provides more detailed information in terms of the potential risk of pesticides to populations than the RQ method.

Inhibitory effect of Anabaena sp. on in situ filtering rate of Daphnia

1986 ◽  
Vol 64 (9) ◽  
pp. 1831-1834 ◽  
Author(s):  
Patricia Chow-Fraser ◽  
W. Gary Sprules
Keyword(s):  
Lake Water ◽  
Laboratory Experiments ◽  
Carapace Length ◽  
Daphnia Pulex ◽  
Biomass Concentration ◽  
Inhibitory Effect ◽  
Filtering Rate ◽  
Anabaena Sp ◽  
Filtering Rates

We found that in situ filtering rates of Daphnia spp. measured in a lake containing Anabaena were significantly lower than those measured in a filament-free lake. Even after accounting for the depressing effects of high nannoplankton biomass concentration, filtering rates in the lake with Anabaena were 64% lower than those from the filament-free lake. We also found that filtering rates for Daphnia pulex in laboratory experiments were lower when Anabaena was present in experimental beakers than when Chlorella was present. When Anabaena was removed from Three Mile Lake water, filtering rates compared closely with predicted rates based on nannoplankton concentration and carapace length alone. Our analysis indicates that the presence of Anabaena filaments depresses Daphnia grazing rates in general, and that the filaments themselves are ingested at a lower rate than algae such as Chlorella.

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