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Mating behavior of Daphnia: impacts of predation risk, food quantity, and reproductive phase of females.

La GH, Choi JY, Chang KH, Jang MH, Joo GJ, Kim HW - PLoS ONE (2014)

Bottom Line: Mating-related behavior involved male-female contact (mating) as well as male-male contact (fighting).Mating frequency increased while unnecessary fighting decreased in the presence of predation risk.In addition, low food concentration reduced fighting between males.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Education, Sunchon National University, Suncheon, Korea.

ABSTRACT
High predation risk and food depletion lead to sexual reproduction in cyclically parthenogenetic Daphnia. Mating, the core of sexual reproduction, also occurs under these conditions. Assessment of the environmental conditions and alteration of mating efforts may aid in determining the success of sexual reproduction. Here, we evaluated the impacts of predation risk, food quantity, and reproductive phase of females on the mating behavior of Daphnia obtusa males including contact frequency and duration using video analysis. Mating-related behavior involved male-female contact (mating) as well as male-male contact (fighting). Mating frequency increased while unnecessary fighting decreased in the presence of predation risk. In addition, low food concentration reduced fighting between males. Males attempted to attach to sexual females more than asexual females, and fighting occurred more frequently in the presence of sexual females. Duration of mating was relatively long; however, males separated shortly after contact in terms of fighting behavior. Thus, assessment of environmental factors and primary sexing of mates were performed before actual contact, possibly mechanically, and precise sex discrimination was conducted after contact. These results suggest that mating in Daphnia is not a random process but rather a balance between predation risk and energetic cost that results in changes in mating and fighting strategies.

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Related in: MedlinePlus

Contact frequencies and duration times of mating and fighting of Daphnia obtusa according to the absence or presence of fish kairomones.Observation was performed for 10 minutes. Each column represents the mean ± SE of 48 replicates.
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pone-0104545-g003: Contact frequencies and duration times of mating and fighting of Daphnia obtusa according to the absence or presence of fish kairomones.Observation was performed for 10 minutes. Each column represents the mean ± SE of 48 replicates.

Mentions: Fish kairomones had obvious and opposite impacts on the frequencies of both mating and fighting. In mating, the mean total contact frequency significantly (p = 0.004) increased from 12.9 to 16.4 in the presence of fish kairomones. On the other hand, the mean total contact frequency during fighting significantly (p = 0.000) decreased from 13.7 to 9.5 (Fig. 3A, B and Table S1) in the presence of fish kairomones. There was no statistical difference in duration time of mating between the control and fish kairomones treatments. Similarly, there was no effect of predation risk on the duration of fights. However, fights were distinctively shorter (0.7∼0.8 sec.) than male–female contact (Fig. 3C, D and Table S1).


Mating behavior of Daphnia: impacts of predation risk, food quantity, and reproductive phase of females.

La GH, Choi JY, Chang KH, Jang MH, Joo GJ, Kim HW - PLoS ONE (2014)

Contact frequencies and duration times of mating and fighting of Daphnia obtusa according to the absence or presence of fish kairomones.Observation was performed for 10 minutes. Each column represents the mean ± SE of 48 replicates.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4128813&req=5

pone-0104545-g003: Contact frequencies and duration times of mating and fighting of Daphnia obtusa according to the absence or presence of fish kairomones.Observation was performed for 10 minutes. Each column represents the mean ± SE of 48 replicates.
Mentions: Fish kairomones had obvious and opposite impacts on the frequencies of both mating and fighting. In mating, the mean total contact frequency significantly (p = 0.004) increased from 12.9 to 16.4 in the presence of fish kairomones. On the other hand, the mean total contact frequency during fighting significantly (p = 0.000) decreased from 13.7 to 9.5 (Fig. 3A, B and Table S1) in the presence of fish kairomones. There was no statistical difference in duration time of mating between the control and fish kairomones treatments. Similarly, there was no effect of predation risk on the duration of fights. However, fights were distinctively shorter (0.7∼0.8 sec.) than male–female contact (Fig. 3C, D and Table S1).

Bottom Line: Mating-related behavior involved male-female contact (mating) as well as male-male contact (fighting).Mating frequency increased while unnecessary fighting decreased in the presence of predation risk.In addition, low food concentration reduced fighting between males.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Education, Sunchon National University, Suncheon, Korea.

ABSTRACT
High predation risk and food depletion lead to sexual reproduction in cyclically parthenogenetic Daphnia. Mating, the core of sexual reproduction, also occurs under these conditions. Assessment of the environmental conditions and alteration of mating efforts may aid in determining the success of sexual reproduction. Here, we evaluated the impacts of predation risk, food quantity, and reproductive phase of females on the mating behavior of Daphnia obtusa males including contact frequency and duration using video analysis. Mating-related behavior involved male-female contact (mating) as well as male-male contact (fighting). Mating frequency increased while unnecessary fighting decreased in the presence of predation risk. In addition, low food concentration reduced fighting between males. Males attempted to attach to sexual females more than asexual females, and fighting occurred more frequently in the presence of sexual females. Duration of mating was relatively long; however, males separated shortly after contact in terms of fighting behavior. Thus, assessment of environmental factors and primary sexing of mates were performed before actual contact, possibly mechanically, and precise sex discrimination was conducted after contact. These results suggest that mating in Daphnia is not a random process but rather a balance between predation risk and energetic cost that results in changes in mating and fighting strategies.

Show MeSH
Related in: MedlinePlus