Morphological defenses of Daphnia against copepod predation on eggs msaccc:1994-10-02

Understanding the long-term controls on cladoceran size structure has important implications for aquatic ecosystems. Although there has been considerable interest in zooplankton size trends for Canadian Shield lakes, data are not available for zooplankton size structure prior to the period of anthropogenic disturbances. Here, we present pre- and post-impact size data for the common pelagic cladocerans Bosmina and Daphnia for 44 well-studied Shield lakes in south-central Ontario (Canada). We show that Daphnia were larger and that the length of Bosmina body appendages (mucrones and antennules) was longer in pre-industrial times than they are today. The reduction in Bosmina appendage length we observed may suggest a reduction in copepod predation pressure since pre-industrial times. Reduced maximum body size in Daphnia is a predicted response to a warming climate in north temperate lakes; however, we suggest that alternate explanations, specifically acidification and subsequent recovery following emission reductions, should also be explored as the primary drivers of Daphnia size changes in this lake set. Overall, our results highlight the importance of pre-impact data for understanding the long-term controls on cladoceran body size from pre-1850 to present.

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Vulnerability of carp larvae to copepod predation as a function of larval age and body length

Aquaculture ◽

10.1016/j.aquaculture.2012.01.001 ◽

2012 ◽

Vol 338-341 ◽

pp. 274-283 ◽

Cited By ~ 9

Author(s):

Ram Kumar ◽

Sami Souissi ◽

Jiang-Shiou Hwang

Keyword(s):

Body Length ◽

Copepod Predation

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Correction for Laforsch et al., An acoustic microscopy technique reveals hidden morphological defenses in Daphnia, PNAS 2004 101:15911-15914

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.0408763101 ◽

2004 ◽

Vol 102 (2) ◽

pp. 515-515

Keyword(s):

Acoustic Microscopy ◽

Microscopy Technique ◽

Morphological Defenses

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The interaction between antipredator behaviour and antipredator morphology: experiments with fathead minnows and brook sticklebacks

Canadian Journal of Zoology ◽

10.1139/z95-261 ◽

1995 ◽

Vol 73 (12) ◽

pp. 2209-2215 ◽

Cited By ~ 50

Author(s):

Mark V. Abrahams

Keyword(s):

Predation Risk ◽

Yellow Perch ◽

Prey Species ◽

Pimephales Promelas ◽

Antipredator Behaviour ◽

Fathead Minnows ◽

Behavioural Modification ◽

Reactive Distance ◽

Habitat Avoidance ◽

Morphological Defenses

Prey species have two fundamental strategies for reducing their probability of being killed by a predator: behavioural modification and morphological defenses. It is hypothesized that prey species which possess morphological defenses should exhibit less behavioural modification in response to predation risk than species lacking such defenses. Experiments were conducted to examine behavioural modification by armoured (brook sticklebacks, Culea inconstans) and unarmoured (fathead minnows, Pimephales promelas) prey species foraging in the presence of a predator (yellow perch, Perca flavescens). Two experiments measured habitat avoidance and reactive distance to an approaching predator. The results of these experiments were consistent with the hypothesis. Compared with fathead minnows, brook sticklebacks exhibited relatively little behavioural modification in response to the presence of a predator, both in terms of avoiding dangerous areas and in their reactive distance to an approaching predator. Sticklebacks, however, graded their reactive distance to an approaching predator in relation to both their body size and group size. These data suggest that the morphology of brook sticklebacks and their behavioural sensitivity to predation risk may allow them to efficiently exploit habitats that contain predators.

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No impact of biocontrol predator on development time or size of surviving Aedes albopictus under optimal nutritional availability

10.1101/2021.09.16.460697 ◽

2021 ◽

Author(s):

Marie C. Russell ◽

Lauren J. Cator

Keyword(s):

Aedes Albopictus ◽

Development Time ◽

Wing Length ◽

Sublethal Effects ◽

Cyclopoid Copepod ◽

Adult Size ◽

Fish Food ◽

Predator Treatment ◽

Copepod Predation ◽

Significant Difference

AbstractBackgroundCyclopoid copepods have been applied successfully to limit populations of highly invasive Aedes albopictus mosquitoes that can vector diseases, including chikungunya, dengue, yellow fever, and Zika, to humans. However, there is concern that changes in certain vector traits, induced by exposure to copepod predation, might increase the risk of disease transmission. In this study, we tested whether cyclopoid copepod predation has sublethal effects on the development time or adult size of Ae. albopictus under the scenario of an invasion in southeast England, which lies at the northern edge of the vector’s expanding global range.MethodsThird instar Ae. albopictus larvae, hereafter referred to as “focal individuals”, were placed in individual Petri dishes, each containing four newly-hatched Ae. albopictus larvae, which were counted, removed, and replaced daily. All focal individuals were provided with fish food ad libitum, and half were exposed to Megacyclops viridis copepod predators. The day of pupation was recorded for each focal individual, and the wing length of each focal adult was also measured.ResultsExposing late instar Ae. albopictus to predation decreased their chances of surviving to adulthood. Mortality of the focal individuals was 12.9% in the predator treatment, and 2.9% in the controls. Three focal larvae that died in the predator treatment showed signs of melanization, indicative of wounding. Among surviving Ae. albopictus, no significant difference in either pupation day or wing length was observed due to copepod predation.ConclusionsWe found that M. viridis predation on smaller Ae. albopictus larvae does not significantly affect the pupation day or adult size of surrounding larger larvae that are less vulnerable to copepod attacks. This study controlled for density effects on size by maintaining a constant number of newly-hatched prey larvae surrounding each focal larva. Those working to control Ae. albopictus populations in the field should be made aware that increased adult body size can occur if copepod biocontrol agents are applied at lower than necessary levels. The absence of a significant sublethal impact from M. viridis copepod predation on surviving later-stage larvae in this analysis supports the use of M. viridis as a biocontrol agent.Graphical abstract

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