Benefits of photosynthesis for insects in galls
Benefits of photosynthesis for insects in galls
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DOI：
10.1007/s00442-012-2365-1
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发表时间：
2012-12-01
期刊：
影响因子：
2.7
通讯作者：
Cramer, M. D.
中科院分区：
文献类型：
--
作者：
Haiden, S. A.;Hoffmann, J. H.;Cramer, M. D.
昆虫诱导的植物瘤主要被认为是强大的碳汇，尽管许多类型的瘤含有叶绿素并具有光合作用的潜力。我们研究了长叶相思叶蜂诱导的芽鳞的光合作用能力是否抵消了幼虫的碳收支或为幼虫提供了O-2，同时消耗了致密的虫胆组织中的CO2，从而将(O-2)和(CO2)维持在幼虫的耐受范围内。在虫胆的内部组织中发现低的(O-2)(<；5%v/v)，并且这些浓度对光只有轻微的反应，这表明虫胆内的光合作用在向幼虫提供O-2方面是不重要的。幼虫对低氧(O-2)和高二氧化碳(CO2)的代谢反应表明，幼虫对低氧/高碳酸血症具有耐受性，并具有降低呼吸频率以应对高碳酸血症的能力。用铝箔遮荫20天的幼虫死亡率较低，这表明光合作用对幼虫的存活并不是至关重要的，尽管遮荫的虫胆的生长大大减少。气体交换测量证实，虽然光合作用从未完全补偿虫胆的呼吸成本，但它对虫胆的维持和生长做出了重大贡献，特别是幼虫的生长，减少了它们作为碳汇对宿主的影响。我们的结论是，虽然光合作用可能有助于提供O-2，但它的主要作用是减少昆虫诱导的根瘤对光合作用产物寄主植物的依赖，从而减少植物内部和根瘤间的竞争，增加每个根瘤成熟的可能性。
Insect-induced plant galls are predominantly reputed to act as strong carbon sinks, although many types of galls contain chlorophyll and have the potential to photosynthesize. We investigated whether the photosynthetic capacity of bud galls induced by a Pteromalid wasp, Trichilogaster acaciaelongifoliae, in Acacia longifolia subsidises carbon budgets or provides O-2 to the larvae while concurrently consuming CO2 in the dense gall tissue, thereby maintaining (O-2) and (CO2) within the range of larval tolerance. Low (O-2) (< 5 % v/v) were found within the internal tissues of galls, and these concentrations responded only marginally to light, suggesting that the photosynthetic activity within the gall is inconsequential in the provision of O-2 to the larvae. The metabolic response of larvae to reduced (O-2) and elevated (CO2) indicated that larvae were tolerant of hypoxia/hypercarbia and also capable of reducing their respiratory rates to cope with hypercarbia. The low mortality of larvae in galls shaded with Al-foil for 20 days showed that photosynthesis was not vital for the survival of the larvae, although growth of shaded galls was substantially reduced. Gas exchange measurements confirmed that, while photosynthesis never fully compensated for the respiratory costs of galls, it contributed substantially to the maintenance and growth, especially of young galls, reducing their impact as carbon sinks on the host. We conclude that, although photosynthesis may contribute to O-2 provision, its main role is to reduce the dependence of the insect-induced gall on the host plant for photosynthates, thereby reducing intra-plant, inter-gall competition and enhancing the probability that each gall will reach maturity.