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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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Typical mating position of Daphnia obtusa.Male (below) grasps the female (above) with freshly ovulated sexual eggs in the immature ephippium.
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pone-0104545-g002: Typical mating position of Daphnia obtusa.Male (below) grasps the female (above) with freshly ovulated sexual eggs in the immature ephippium.

Mentions: Mating behavior in D. obtusa involved two types of contact; male–female contact (mating) and male–male contact (fighting). Males frequently changed their swimming direction toward individuals that passing nearby and chased the tracks of females or other males. Normally, mating behavior involved a strong escape response with fast swimming until the male became detached from the female. This reaction was also observed in fighting. Initially, males approached females from various directions, grasped a female with its modified hook-like first antennules, positioned itself on the ventral side, and attempted to insert its abdominal claw into the carapace valve of the female for insemination (Fig. 2).


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)

Typical mating position of Daphnia obtusa.Male (below) grasps the female (above) with freshly ovulated sexual eggs in the immature ephippium.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0104545-g002: Typical mating position of Daphnia obtusa.Male (below) grasps the female (above) with freshly ovulated sexual eggs in the immature ephippium.
Mentions: Mating behavior in D. obtusa involved two types of contact; male–female contact (mating) and male–male contact (fighting). Males frequently changed their swimming direction toward individuals that passing nearby and chased the tracks of females or other males. Normally, mating behavior involved a strong escape response with fast swimming until the male became detached from the female. This reaction was also observed in fighting. Initially, males approached females from various directions, grasped a female with its modified hook-like first antennules, positioned itself on the ventral side, and attempted to insert its abdominal claw into the carapace valve of the female for insemination (Fig. 2).

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