Predation Risk, Prey Behavior, and Feeding Rate in Daphnia pulex

1992 ◽  
Vol 49 (1) ◽  
pp. 159-165 ◽  
Author(s):  
Charles W. Ramcharan ◽  
Stanley I. Dodson ◽  
Jason Lee
Keyword(s):  
Antipredator Behavior ◽  
Phenotypic Expression ◽  
Daphnia Pulex ◽  
Spatial Separation ◽  
Antipredator Defense ◽  
Feeding Experiments ◽  
Prey Behavior ◽  
Morphological Defense ◽  
Genetically Determined ◽  
Vulnerable Adults

Exposure to chemical exudates from the planktonic invertebrate predator Chaohorus americanus causes the prey Daphnia pulex to migrate upwards in the water column of laboratory experimental chambers. This behavior is an antipredator defense that results in spatial separation of Daphnia from Chaoborus, since this predator tends to remain near the bottom of the chambers. We test the effects of prey vulnerability, genotype, prior exposure to predators, and predator density on antipredator behavior of D. pulex. To study differences in vulnerability, we compared two genotypes of Daphnia that differed in their ability to produce a morphological defense (growth of neck spines) when exposed to Chaohorus chemical. Overall, behavioral responses to Chaoborus were stronger at higher predator densities. Juvenile Daphnia that are most vulnerable to Chaoborus predation had stronger responses than the less vulnerable adults. Neither genetically determined ability to produce neck spines nor phenotypic expression of neck spines affected strength of antipredator behavior. Vertical migration to avoid Chaoborus may have an ecological cost. Presence of Chaoborus reduced ingestion rates of juvenile Daphnia at low food levels (5 × 103 algal cells∙mL−1). Feeding experiments also showed differences in feeding characteristics of two different clones of D. pulex.

scholarly journals Genetic correlations across genetically determined and developmentally plastic alternative reproductive tactics

2019 ◽  
Author(s):  
Jessica K. Abbott ◽  
Oscar Rios-Cardenas ◽  
Molly Morris
Keyword(s):  
Body Size ◽  
Genetic Correlation ◽  
Genetic Correlations ◽  
Phenotypic Expression ◽  
Alternative Reproductive Tactics ◽  
Phenotypic Trait ◽  
Sexual Antagonism ◽  
Reproductive Tactics ◽  
Genetic Conflict ◽  
Genetically Determined

AbstractAlternative reproductive tactics occur when individuals of the same sex have a suite of morphological and/or behavioural traits that allow them to pursue different reproductive strategies. A common pattern is e.g. the existence of “courter” and “sneaker” tactics within males. We have previously argued that alternative reproductive tactics should be subject to genetic conflict over the phenotypic expression of traits, similar to sexual antagonism. In this process, which we called intra-locus tactical conflict, genetically determined tactics experience conflicting selection on a shared phenotypic trait, such as body size, but a positive genetic correlation between tactics in body size prevents either tactic from reaching its optimum. Recently, other authors have attempted to extend this idea to developmentally plastic alternative reproductive tactics, with mixed results. However, it is not clear whether we should expect intra-locus tactical conflict in developmentally plastic tactics or not. We have therefore run a series of simulation models investigating under what conditions we should expect to see positive estimates of the inter-tactical genetic correlation, since a positive genetic correlation is a prerequisite for the existence of intra-locus tactical conflict. We found that for autosomal, X-linked, and Y-linked genetically-determined tactics, estimated inter-tactical genetic correlations were generally high. However, for developmentally plastic tactics, the genetic correlation depends on the properties of the switching threshold between tactics. If it is fixed, then estimated genetic correlations are positive, but if there is genetic variation in the switch-point, then any sign and magnitude of estimated genetic correlation is possible, even for highly heritable traits where the true underlying correlation is perfect. This means that caution should be used when investigating genetic constraints in plastic phenotypes.

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.

The influence of benthic tundra pond vegetation and prey behavior on Zooplankton predation by the flatworm Mesostoma lingua

1985 ◽  
Vol 63 (7) ◽  
pp. 1617-1621 ◽  
Author(s):  
Hugh J. MacIsaac ◽  
Thomas C. Hutchinson
Keyword(s):  
Daphnia Pulex ◽  
Chironomus Riparius ◽  
Alternative Prey ◽  
Prey Behavior ◽  
Predation Rates ◽  
Branchinecta Paludosa

Experiments were conducted at the Smoking Hills and Tuktoyaktuk, N.W.T., to determine if Mesostoma lingua, a common pond inhabitant, preys selectively on co-occurring Zooplankton, and whether predation rates are affected by the presence of pond vegetation. Experiments were conducted in 250-mL containers at the sites. Mesostoma fed heavily on Daphnia pulex and Chironomus riparius, but not on Branchinecta paludosa or Diaptomus arcticus. The presence of alternative prey led to significant reductions in Daphnia predation rates, while the presence of the pond plants Cladophora insignis and Drepanocladus aduncus, which provide shelter and cover, significantly increased predation rates. The advantage of the moss and algal habitat was largely to the predator.

scholarly journals Thalassemia Intermedia

Blood ◽  
1964 ◽  
Vol 23 (6) ◽  
pp. 829-838 ◽  
Author(s):  
HOWARD A. PEARSON ◽  
WARD D. NOYES
Keyword(s):  
Clinical Studies ◽  
Phenotypic Expression ◽  
Individual Factors ◽  
Minor Components ◽  
Thalassemia Intermedia ◽  
Hematologic Disease ◽  
Biochemical Genetic ◽  
Genetically Determined

Abstract Biochemical, genetic, and clinical studies of two adult Negro brothers with clinical thalassemia intermedia are presented. Their hematologic disease appears to have been caused by interactions of thalassemia with another gene which had no phenotypic expression or was non-allelic to the thalassemia locus. These men had striking differences in the proportions of the minor components Hb A2 and F. It is considered unlikely that these differences were genetically determined. Rather, it is suggested that environmental or individual factors can modify this biochemical expression of thalassemia genes.

scholarly journals Effects of steroid hormones and xenobiotics on the pubertal development of UDP-glucuronosyltransferase activities towards androsterone and 4-nitrophenol in Wistar rats

1984 ◽  
Vol 222 (2) ◽  
pp. 321-326 ◽  
Author(s):  
H K Watanabe ◽  
M Matsui
Keyword(s):  
High Activity ◽  
Steroid Hormones ◽  
Wistar Rats ◽  
Pubertal Development ◽  
Suppressive Effect ◽  
Feeding Experiments ◽  
Oestradiol Benzoate ◽  
Old Rats ◽  
Udp Glucuronosyltransferase ◽  
Genetically Determined

Oestradiol benzoate, testosterone propionate, progesterone, corticosterone, 3-methylcholanthrene and phenobarbital were administered to Wistar rats at the pubertal period, and their effects on hepatic UDP-glucuronosyltransferase activities were determined. Pretreatment with oestradiol benzoate had a temporary suppressive effect on androsterone UDP-glucuronosyltransferase activity in rats with the high-activity phenotype of androsterone glucuronidation. The effect was marked in 40-day-old rats, but was not found in older rats. Androsterone UDP-glucuronosyltransferase activity was induced by phenobarbital in rats with the high-activity phenotype, but not in rats with the low-activity phenotype. Foster-feeding experiments showed that breast milk did not alter the genetically determined expression of androsterone UDP-glucuronosyltransferase activity in Wistar rats. In contrast, 4-nitrophenol UDP-glucuronosyltransferase activity was not affected by steroid hormones, but was highly induced by 3-methylcholanthrene.

Spontaneous and induced activation of genes affecting the phenotypic expression of glucose 6-phosphate dehydrogenase in Daphnia pulex

1983 ◽  
Vol 189 (3) ◽  
pp. 485-489 ◽  
Author(s):  
A. O. Ruvinsky ◽  
Yu. I. Lobkov ◽  
D. K. Belyaev
Keyword(s):  
Phenotypic Expression ◽  
Daphnia Pulex ◽  
Glucose 6 Phosphate Dehydrogenase

scholarly journals Antipredator behavior of newts (Cynops pyrrhogaster) against snakes

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0258218
Author(s):  
Koji Mochida ◽  
Akira Mori
Keyword(s):  
Low Temperature ◽  
Antipredator Behavior ◽  
Chemical Defenses ◽  
Body Parts ◽  
Control Stimulus ◽  
Warm Temperature ◽  
Antipredator Defense ◽  
Cynops Pyrrhogaster ◽  
Temperature Conditions ◽  
Specific Predator

Newts and salamanders show remarkable diversity in antipredator behavior, developed to enhance their chemical defenses and/or aposematism. The present study reports on the antipredator behavior of newts (Cynops pyrrhogaster) in response to snakes. Newts displayed a significant amount of tail-wagging and tail-undulation in response to a contact stimulus from the snake’s tongue, which is a snake-specific predator stimulus, as compared to a control stimulus (behavioral scores: tongue, 1.05 ± 0.41; control, 0.15 ± 0.15). Newts that were kept in warm temperature conditions, 20°C (at which snakes are active in nature), performed tail displays more frequently than newts kept in low-temperature conditions, 4°C (at which snakes are inactive in nature). Our results suggest that the tail displays of C. pyrrhogaster could function as an antipredator defense; they direct a snake’s attention to its tail to prevent the snake from attacking more vulnerable body parts. We also discussed the reason for inter-populational variation in the tendency of newts to perform tail displays.

scholarly journals The antipredator benefits of postural camouflage in peppered moth caterpillars

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hannah M. Rowland ◽  
Robert P. Burriss ◽  
John Skelhorn
Keyword(s):  
Natural Selection ◽  
Ambient Temperature ◽  
Food Availability ◽  
Energetic Cost ◽  
Antipredator Defense ◽  
Prey Behavior ◽  
Series Of Experiments ◽  
Ad Libitum

AbstractCamouflage is the most common form of antipredator defense, and is a textbook example of natural selection. How animals’ appearances prevent detection or recognition is well studied, but the role of prey behavior has received much less attention. Here we report a series of experiments with twig-mimicking larvae of the American peppered moth Biston betularia that test the long-held view that prey have evolved postures that enhance their camouflage, and establish how food availability and ambient temperature affect these postures. We found that predators took longer to attack larvae that were resting in a twig-like posture than larvae resting flat against a branch. Larvae that were chilled or food restricted (manipulations intended to energetically stress larvae) adopted a less twig-like posture than larvae that were fed ad libitum. Our findings provide clear evidence that animals gain antipredator benefits from postural camouflage, and suggest that benefits may come at an energetic cost that animals are unwilling or unable to pay under some conditions.

Spontaneous and induced activation of genes affecting the phenotypic expression of glucose 6-phosphate dehydrogenase in Daphnia pulex

1986 ◽  
Vol 72 (6) ◽  
pp. 811-815 ◽  
Author(s):  
A. O. Ruvinsky ◽  
Yu. I. Lobkov ◽  
D. K. Belyaev
Keyword(s):  
Phenotypic Expression ◽  
Daphnia Pulex ◽  
Glucose 6 Phosphate Dehydrogenase

Spontaneous and induced activation of genes affecting the phenotypic expression of glucose 6-phosphate dehydrogenase in Daphnia pulex

1983 ◽  
Vol 189 (3) ◽  
pp. 490-494 ◽  
Author(s):  
A. O. Ruvinsky ◽  
Yu. I. Lobkov ◽  
D. K. Belyaev
Keyword(s):  
Phenotypic Expression ◽  
Daphnia Pulex ◽  
Glucose 6 Phosphate Dehydrogenase
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