Deep-ocean biology has been the least explored—although rapidly growing—area of research. In particular, behavior, reproduction and ecology of deeper-living squids remain poorly documented due to the extreme difficulties of encountering and capturing them. Here we report on a mature/maturing female giant squid, Architeuthis dux, caught as by-catch in a fishery set-net. Microsatellite paternity analysis was carried out on the implanted spermatangia scattered widely over the body surface. Using genomic DNA from 42 Architeuthis individual muscle tissue specimens, four polymorphic microsatellite markers were developed, of which three were used for genotyping. Surprisingly, it was found that all 66 of the successfully genotyped spermatangia located on five different body parts were derived from a single male, suggesting that only single-pair copulation can lead to entire sperm loading. From this result and previous findings, the possibilities of the reproductive mode of this species are explored in the light of postcopulatory sexual selection mechanisms.

深海生物学一直是探索最少——尽管发展迅速——的研究领域。特别是，由于遇到和捕获它们的极端困难，更深层次生活的鱿鱼的行为、繁殖和生态仍然缺乏记录。在这里，我们报告了一种成熟/成熟的雌性巨型鱿鱼Architeuthis dux，在渔业固定网中作为副渔获物捕获。对广泛散布在体表的植入精子进行了微卫星亲子鉴定。使用来自 42 Architeuthis 的基因组 DNA单个肌肉组织标本，开发了四个多态性微卫星标记，其中三个用于基因分型。令人惊讶的是，发现位于五个不同身体部位的所有 66 个成功基因分型的精原细胞都来自单个男性，这表明只有单对交配才能导致整个精子负荷。根据这一结果和先前的发现，根据交配后的性选择机制探索了该物种生殖模式的可能性。