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Effects of algal food quality on sexual reproduction of Daphnia magna.

Choi JY, Kim SK, La GH, Chang KH, Kim DK, Jeong KY, Park MS, Joo GJ, Kim HW, Jeong KS - Ecol Evol (2016)

Bottom Line: From the results, we found that the mating frequency and copulation duration increased in the treatment with S. hantzschii, resulting in a significant increase of hatching rates of resting eggs.In the other two repetitive mating strategies (e.g., one female vs. multiple males, and one male vs. multiple females), we found that the hatching rates of resting eggs were greater in the S. hantzschii treatment.In summary, our study manifested that diatom consumption of D. magna leads to more successful sexual reproduction.

View Article: PubMed Central - PubMed

Affiliation: National Institute of Ecology Seo-Cheon Gun Chungcheongnam Province 325-813 Korea.

ABSTRACT
The objective of our study was to investigate sexual reproduction of Daphnia magna associated with mating behaviors and hatching rates, according to different algal food sources. Since a diatom is known to contain more abundant long-chain poly unsaturated fatty acids (PUFAs), we hypothesized that the diatom-consuming D. magna would exhibit more successful reproduction rates. Upon the hypothesis, we designed three experiments using two algal species, a green alga (Chlorella vulgaris) and a diatom (Stephanodiscus hantzschii). From the results, we found that the mating frequency and copulation duration increased in the treatment with S. hantzschii, resulting in a significant increase of hatching rates of resting eggs. In the other two repetitive mating strategies (e.g., one female vs. multiple males, and one male vs. multiple females), we found that the hatching rates of resting eggs were greater in the S. hantzschii treatment. In addition to the mating strategy, male body size significantly increased in the diatom treatment, hence average diameter of penis was also statistically different among the treatments (greater diameter in the S. hantzschii treatment). To examine the effect of algal food quality, we estimated quantity of fatty acids in the two algal species. Our result showed that S. hantzschii had a higher proportion of long-chain PUFAs than C. vulgaris. Furthermore, a stable isotope analysis revealed that carbon and nitrogen originated from S. hantzschii were more assimilated to D. magna. In summary, our study manifested that diatom consumption of D. magna leads to more successful sexual reproduction. We then discussed how the diatom consumption of zooplankton influences food web dynamics in a freshwater ecosystem.

No MeSH data available.


An image showing the length and width of male Daphnia magna penis.
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ece32058-fig-0003: An image showing the length and width of male Daphnia magna penis.

Mentions: We collected the males used in the mating experiment after termination of the experiment, and stored them in ethanol. Using a microscope, we obtained the image of the males in order to measure their body length (×400 magnification, AxioScope 40; Carl Zeiss Microscopy, Germany). Then, we eviscerated penises under the microscope, and took microscopic images of the penis samples as well. Body length, size of penises (width and length) were measured using an image processing program (AxioVision Rel 4.8; Carl Zeiss Microscopy; Fig. 3), and the measurements were compared with respect to food algal treatments.


Effects of algal food quality on sexual reproduction of Daphnia magna.

Choi JY, Kim SK, La GH, Chang KH, Kim DK, Jeong KY, Park MS, Joo GJ, Kim HW, Jeong KS - Ecol Evol (2016)

An image showing the length and width of male Daphnia magna penis.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4863008&req=5

ece32058-fig-0003: An image showing the length and width of male Daphnia magna penis.
Mentions: We collected the males used in the mating experiment after termination of the experiment, and stored them in ethanol. Using a microscope, we obtained the image of the males in order to measure their body length (×400 magnification, AxioScope 40; Carl Zeiss Microscopy, Germany). Then, we eviscerated penises under the microscope, and took microscopic images of the penis samples as well. Body length, size of penises (width and length) were measured using an image processing program (AxioVision Rel 4.8; Carl Zeiss Microscopy; Fig. 3), and the measurements were compared with respect to food algal treatments.

Bottom Line: From the results, we found that the mating frequency and copulation duration increased in the treatment with S. hantzschii, resulting in a significant increase of hatching rates of resting eggs.In the other two repetitive mating strategies (e.g., one female vs. multiple males, and one male vs. multiple females), we found that the hatching rates of resting eggs were greater in the S. hantzschii treatment.In summary, our study manifested that diatom consumption of D. magna leads to more successful sexual reproduction.

View Article: PubMed Central - PubMed

Affiliation: National Institute of Ecology Seo-Cheon Gun Chungcheongnam Province 325-813 Korea.

ABSTRACT
The objective of our study was to investigate sexual reproduction of Daphnia magna associated with mating behaviors and hatching rates, according to different algal food sources. Since a diatom is known to contain more abundant long-chain poly unsaturated fatty acids (PUFAs), we hypothesized that the diatom-consuming D. magna would exhibit more successful reproduction rates. Upon the hypothesis, we designed three experiments using two algal species, a green alga (Chlorella vulgaris) and a diatom (Stephanodiscus hantzschii). From the results, we found that the mating frequency and copulation duration increased in the treatment with S. hantzschii, resulting in a significant increase of hatching rates of resting eggs. In the other two repetitive mating strategies (e.g., one female vs. multiple males, and one male vs. multiple females), we found that the hatching rates of resting eggs were greater in the S. hantzschii treatment. In addition to the mating strategy, male body size significantly increased in the diatom treatment, hence average diameter of penis was also statistically different among the treatments (greater diameter in the S. hantzschii treatment). To examine the effect of algal food quality, we estimated quantity of fatty acids in the two algal species. Our result showed that S. hantzschii had a higher proportion of long-chain PUFAs than C. vulgaris. Furthermore, a stable isotope analysis revealed that carbon and nitrogen originated from S. hantzschii were more assimilated to D. magna. In summary, our study manifested that diatom consumption of D. magna leads to more successful sexual reproduction. We then discussed how the diatom consumption of zooplankton influences food web dynamics in a freshwater ecosystem.

No MeSH data available.