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Updated: May 31, 2025

Observation and Quantification of Mating Behavior in the Pinewood Nematode, Bursaphelenchus xylophilus
Published on: December 25, 2016
Alternative mating pattern in Enoploteuthis chunii is associated with polyandry and male-biased sex ratio
Yuu Moriwaki1, Satoshi Kusama2, Anri Yamane3
1Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane, Japan.
Abstract:
Although cephalopods are primarily polyandrous, genetic evidence revealed rare monogamy in Watasenia scintillans . Here, we studied the sister species Enoploteuthis chunii . We found that copulation began in early July, with egg spawning occurring in early August. The sex ratio was female-biased until late August, then shifted to male-biased. After early August, the average number of sperm sacs in females exceeded that of males. As the season progresses, females began storing sperm sacs in a cryptic sperm pocket on the right lateral trunk within the mantle. This behavior is associated with male-biased sex ratio. These results suggest polyandry in E. chunii.
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