Mikheev V N, Pasternak A F, Valtonen E T
Institute of Ecology and Evolution, Russian Academy of Sciences, Laboratory of Behaviour of Lower Vertebrates, 119071 Moscow, Leninskii prospekt, 33.
Zh Obshch Biol. 2003 May-Jun;64(3):238-47.
Features of the Argulus foliaceus and A. coregoni life cycles including spatial distribution and hatching patterns of the resting eggs as well as their host searching behaviour were analyzed on the basis of field and experimental data obtained in lakes and a fish farm in the Central Finland. Published data on behaviour and ecology of these parasites were also used. The main point of this analysis was an ecological adjustment of the life cycles of parasites to that of their fish hosts at different spatial and temporal scales. Due to different spatial distribution of overwintering eggs, the newly hatched larvae of A. coregoni are more likely to attach to salmonids, which are their main hosts, while A. foliaceus to percids and cyprinids. The main peak of argulid hatching occurs in late spring-early summer and coincides with the period when most of freshwater fishes concentrate close to the shore, either for spawning, or, foraging. Nevertheless, despite the general coincidence, the parasite-host encounter rate could still be very low. The main peak of hatching is followed by a long "tail". We suggest that under fluctuating and uncertain environmental conditions characterised by both abiotic stochasticity and poor predictability of the hosts, an optimal recruitment strategy is to hedge a bet, with a proportion of eggs synchronously hatching and a proportion remaining dormant and hatching at much lower rate during an extended period. One of the main behavioural adaptations to match with the hosts is all-over-the-day searching activity of argulids. The boreal A. coregoni relies primarily on vision, which is most effective in transparent waters during long polar days in summer. Vision is also important in the behavioural repertoire of the temperate A. foliaceus in the light, but olfaction and mechanoreception in the dark provide the highest host searching rate. The two generally sympatric species of argulids segregated on the finer habitat scale. Partially overlapping on salmonid hosts, they prefer ecologically distinct categories of fish, and use different microhabitats for egg laying and searching for hosts.
基于在芬兰中部的湖泊和一个养鱼场获得的野外及实验数据，分析了叶状鱼虱（Argulus foliaceus）和科氏鱼虱（A. coregoni）的生活史特征，包括滞育卵的空间分布和孵化模式以及它们寻找宿主的行为。还使用了已发表的关于这些寄生虫行为和生态学的数据。该分析的重点是寄生虫生活史在不同空间和时间尺度上对其鱼类宿主生活史的生态适应性。由于越冬卵的空间分布不同，科氏鱼虱新孵化的幼虫更有可能附着在其主要宿主鲑科鱼类上，而叶状鱼虱则更倾向于附着在鲈科和鲤科鱼类上。鱼虱孵化的主要高峰期出现在春末夏初，与大多数淡水鱼集中在岸边产卵或觅食的时期相吻合。然而，尽管总体上时间吻合，但寄生虫与宿主的相遇率可能仍然很低。孵化高峰期之后是一个长长的“尾巴”。我们认为，在以非生物随机性和宿主预测性差为特征的波动且不确定的环境条件下，一种最优的补充策略是进行风险对冲，即一部分卵同步孵化，另一部分保持休眠状态并在较长时期内以低得多的速率孵化。与宿主相匹配的主要行为适应之一是鱼虱全天的搜索活动。北方的科氏鱼虱主要依靠视觉，在夏季漫长的极昼期间，视觉在透明水域中最为有效。视觉在温带叶状鱼虱的行为模式中在有光时也很重要，但在黑暗中嗅觉和机械感受提供了最高的宿主搜索率。这两种通常同域分布的鱼虱在更精细的栖息地尺度上有所分离。它们在鲑科宿主上部分重叠，但更喜欢生态上不同类别的鱼类，并使用不同的微生境来产卵和寻找宿主。
