Sperm removal behavior of the cuttlefish Sepia esculenta(10.7MB, 00:00:37)Shot Date: 2000/03/29 | ||
 | species Sepia esculenta Key Words | |
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Sperm removal behavior of the cuttlefish Sepia esculenta(10.7MB, 00:00:37)Shot Date: 2000/03/29 | ||
| species Sepia esculenta Key Words | |
|
Animalia >Mollusca >Cephalopoda >Sepiida >Sepiidae >Sepia >
Male and female of the cuttlefish Sepia esculenta mate in a head-to-head position. Before ejaculation, the male cuttlefish scrapes out sperm masses attached on the buccal membranes of the paired female using his arms. This sperm removal behavior reduces rival males' sperm, thereby increasing reproductive success (i.e., number of offspring) of the removing male. Noteworthy is that the removed sperm mass debris is directly visible, which is the first observance to be reported among animals, even including enormous numbers of insect species. The video format is ¡Èmov¡É, and the file was compressed using the ¡Èsorenson¡É codec.
Below is the abstract from the article containing this video:
Sperm displacement behavior of cuttlefish (Sepia esculenta) was observed in a tank. Before ejaculation, male cuttlefish used their arms III to scrape out sperm masses attached on the buccal membranes of females. The removed sperm mass debris was directly visible and countable. Since active sperm were present within the removed sperm debris, implying that the aim of this behavior is to remove competing male sperm. However, many sperm masses remained on the female buccal membrane even after the removal behavior, showing that sperm removal in S. esculenta is incomplete. The duration of sperm removal (an indicator of male investment in that process) was unaffected by the body sizes of mated pair, the duration of spermatangia placement at the current mating (for the hypothesis that the sperm removal serves creating attachment space of spermatophores), or the estimated amount of sperm masses deposited from previous matings. Moreover, male S. esculenta performed sperm removal regardless of whether the last male to mate with the partner was himself, suggesting males remove not only the sperm of rivals but also their own. Although the number of removed sperm masses increased with the time spent on removal of sperm, male cuttlefish may shorten the duration of sperm removal to avoid the risk of mating interruption. We conclude that this time restriction likely would influence the degree of partial sperm removal in S. esculenta.
Toshifumi Wada, Takeshi Takegaki, Tohru Mori and Yutaka Natsukari (2005)
Sperm displacement behavior of the cuttlefish Sepia esculenta (Cephalopoda: Sepiidae). J. Ethol. DOI 10.1007/s10164-005-0146-6
(Data No.momo040729se01a)
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