ABSTRACT The life histories of two common boreal-Arctic bryozoans – Electra pilosa and Callopora craticula – living on kelps in the White Sea are described for the first time using colony mapping. Colony functional dynamics (sexual, feeding, budding and rejuvenation) was traced seasonally via recording zooidal states. During the ice-free season the population of the zygote spawner E. pilosa was represented by three generations – overwintered (maternal) and two young ones (daughter and granddaughter). The overwintered colonies exhibited two-phased reproduction and the ‘early’ daughter colonies reproduced just once. ‘Late’ colonies, together with the granddaughter generation, remained sterile. Four generations are described for the brooder C. craticula, three of which continuously produced larvae. While the two species co-exist on the same substratum, reproduction in E. pilosa started almost 1 month later (in late June), which could be explained by the insufficient abundance of phytoplankton in early summer to support the start of oogenesis and feeding cyphonautes larvae. The estimated maximal colony lifespan is 13 months in E. pilosa and 15 months in C. craticula. The broad comparison of bryozoan reproductive ecology in the White Sea showed that their life histories are much more diverse, complex and evolutionarily flexible than previously acknowledged.

中文翻译：

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伊莱克特拉与卡洛波拉：两种苔藓动物在白海的繁殖策略截然不同

摘要 首次使用群体绘图描述了生活在白海海带上的两种常见的北方 - 北极苔藓动物 - Electra pilosa 和 Callopora craticula 的生活史。通过记录动物状态按季节追踪菌落功能动态（性、进食、萌芽和恢复活力）。在无冰季节，受精卵产卵者 E. pilosa 的种群由三代代表——越冬（母系）和两代幼体（女儿和孙女）。越冬菌落表现出两阶段繁殖，而“早期”子代菌落仅繁殖一次。“晚”的殖民地，连同孙女一代，仍然不育。描述了育雏 C. craticula 的四代，其中三代连续产生幼虫。虽然这两个物种在同一基质上共存，但 E. pilosa 的繁殖在近 1 个月后（6 月下旬）开始，这可能是由于初夏浮游植物的丰度不足以支持卵子发生和喂养 cyphonautes幼虫。估计的最大菌落寿命在 E. pilosa 中为 13 个月，在 C. craticula 中为 15 个月。对白海苔藓虫生殖生态的广泛比较表明，它们的生活史比以前承认的更加多样化、复杂和进化灵活。pilosa 和 15 个月 C. craticula。对白海苔藓虫生殖生态的广泛比较表明，它们的生活史比以前承认的更加多样化、复杂和进化灵活。pilosa 和 15 个月的 C. craticula。对白海苔藓虫生殖生态的广泛比较表明，它们的生活史比以前承认的更加多样化、复杂和进化灵活。