Lethal and sub-lethal effects of phototrophic endoliths attacking the shell of the intertidal mussel Perna perna
Lethal and sub-lethal effects of phototrophic endoliths attacking the shell of the intertidal mussel Perna perna
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DOI：
10.1007/s002270050650
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发表时间：
1999-12-01
期刊：
影响因子：
2.4
通讯作者：
McQuaid, CD
中科院分区：
文献类型：
--
作者：
Kaehler, S;McQuaid, CD
动物钻进钙质物质会对软体动物贝壳造成相当大的损害。相比之下，较小的微生物光养内层直到最近才被认为是相对良性的。光养内胚层(主要是蓝藻)寄生在贻贝Perna Perna(L.)中岸种群的贝壳中。在南非。这种侵扰导致明显的外壳退化，我们在这里记录了内胚层对贻贝宿主的重要的致命和亚致命影响(例如，生长和生殖输出的变化)。Endolith的侵染显著降低了贝壳的强度，也影响了贝壳的生长。用荧光钙黄绿素对贝壳进行原位标记，结果表明，感染和未感染贻贝的贝壳长度以相同的速度增长。然而，贝壳厚度的增加速度(与贝壳修复相关)在有虫害的个体中明显快于未受虫害的个体。壳层增厚速度的增加不足以补偿内胚层引起的壳层快速降解，并且在内收肌附着处周围，被感染的贝壳比未被感染的贝壳更薄。在新近死亡的贻贝中，有18%的贝壳因内胚层侵蚀而出现孔洞。这种影响高度依赖于大小，对于最大的贻贝来说，由于内石块而死亡的比例上升到近50%。贝壳修复引起的能量转移对贻贝的繁殖率有重要的亚致死效应。在繁殖期，大型(>；70 mm)、未受感染的Perna的平均干肉质量显著高于受感染的个体。这种差异几乎完全是由于性腺质量的差异，在没有感染的贻贝中，性腺质量大约高出100%。我们的结论是，通过攻击贝壳，光养内胚层降低了中岸大型贻贝的寿命和繁殖产量。
Animals that bore into calcareous material can cause considerable damage to molluscan shells. In contrast, smaller microbial phototrophic endoliths have until recently been thought of as relatively benign. Phototrophic endoliths (primarily cyanobacteria) infest the shells of 50 to 80% of midshore populations of the mussel Perna perna (L.) in South Africa. This infestation causes clearly visible shell degradation, and we record here ecologically important lethal and sub-lethal effects (e.g. changes in growth and reproductive output) of the endoliths on their mussel hosts. Endolith infestation reduced the strength of shells significantly and also affected shell growth. Insitu marking of shells, using the fluorochrome calcein, showed that infested and non-infested mussels increased in shell length at the same rate. However, the rate of increase in shell thickness (associated with shell repair) was significantly faster in infested than in uninfested individuals. This increase in the rate of shell thickening was not sufficient to compensate for rapid endolith-induced shell degradation and, around the site of adductor muscle attachment, infested shells were thinner than their uninfested counterparts. The shells of 18% of recently dead mussels had holes induced by endolith erosion. This effect was highly size dependent, and the proportion of mortality due to endoliths rose to almost 50% for the largest mussels. The re-routing of energy due to shell repair had important sub-lethal effects on the reproductive rates of mussels. During the reproductive period, mean dried flesh mass for large (>70 mm), non-infested P. perna was substantially higher than for infested individuals. This difference was almost entirely due to differences in gonad mass, which was approximately 100% higher for non-infested mussels. We conclude that, by attacking the shell, phototrophic endoliths reduce both the longevity and reproductive output of large mussels on the midshore.