MEPS 298:219-228 (2005)  -  doi:10.3354/meps298219

Dependence of paternity rates onalternative reproductive behaviors in the squidLoligo bleekeri

Y. Iwata1,*, H. Munehara2, Y. Sakurai1

1Graduate School of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate, Hokkaido 041-8611, Japan
2Usujiri Fisheries Station, Field Science Center for Northern Biosphere, Hokkaido University, 152 Usujiri-cho, Hakodate, Hokkaido 041-1613, Japan

ABSTRACT: The mating behavior of captive Loligo bleekeri and the paternity of the resulting progeny were examined based on behavioral observations and genetic analyses. In this species, there are 3 mating behaviors (male-parallel, head-to-head, and extra-pair), and 2 sperm storage sites in females (seminal receptacle and the opening of the oviduct), which suggest that sperm competition occurs. All 3 mating behaviors were observed, and females mated often with different males, resulting in multiple paternity within 3 of the 4 broods examined. In each brood, the male to mate last and frequently before the female spawned fertilized the most eggs (87 to 100%). A sneaker male that mated by extra-pair copulation sired 8.5% of the eggs in a brood. Some eggs were fertilized by sperm received before the start of the study, indicating that sperm can be stored for at least several days before a spawning. In the broods with multiple paternity, the paternity patterns differed among egg capsules. Male competition was more intense between similar-sized males than between different-sized males, but body size did not affect the copulative success in the male-parallel position. We found multiple mating and multiple paternity in L. bleekeri. Paternity rates differed on the complex of factors, rating position, timing, frequency und duration. Alternative reproductive behaviors would change these factors and lead to different paternity rates.


KEY WORDS: Multiple paternity · Reproductive strategy · Squid · Loligo · Microsatellite · Sperm competition


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