Plant, Soil, and Entomological Sciences, University of Idaho, Moscow, ID, 83844, USA.
J Chem Ecol. 2013 Jul;39(7):840-59. doi: 10.1007/s10886-013-0306-z. Epub 2013 Jun 23.
We provide a synthesis of the literature describing biochemical interactions between microorganisms and insects by way of microbial volatile organic compound (MVOC) production. We evaluated the functionality and ecological context of MVOC signals, and explored important metabolic pathways involved in MVOC production. The cosmopolitan distribution of microorganisms creates a context for frequent, and frequently overlooked, insect responses to microbial emissions. There are numerous instances of MVOCs being closely associated with insect feeding behaviors, but some MVOCs are also powerful repellants. Emissions from microorganisms in situ may signal aspects of habitat suitability or potential exposure to entomopathogens. In some ecosystems, bacterial or fungal volatiles can also incite insect aggregations, or MVOCs can resemble sexual pheromones that elicit mating and oviposition behaviors from responding insects. A single microorganism or MVOC can have different effects on insect behaviors, especially across species, ontogenies, and habitats. There appears to be a multipartite basis for insect responses to MVOCs, and complex tritrophic interactions can result from the production of MVOCs. Many biochemical pathways for behaviorally active volatile production by microbial species are conserved across large taxonomic groupings of microorganisms. In addition, there is substantial functional redundancy in MVOCs: fungal tissues commonly produce polyketides and short-chain alcohols, whereas bacterial tissues tend to be more commonly associated with amines and pyrazines. We hypothesize that insect olfactory responses to emissions from microorganisms inhabiting their sensory environment are much more common than currently recognized, and that these signals represent evolutionarily reliable infochemicals. Insect chemoreception of microbial volatiles may contribute to the formation of neutral, beneficial, or even harmful symbioses and provide considerable insight into the evolution of insect behavioral responses to volatile compounds.
我们提供了对微生物挥发有机化合物（MVOC）产生过程中描述微生物与昆虫之间生化相互作用的文献综述。我们评估了 MVOC 信号的功能和生态背景，并探索了涉及 MVOC 产生的重要代谢途径。微生物的世界性分布为昆虫对微生物排放的频繁、但经常被忽视的反应创造了条件。有许多实例表明，MVOC 与昆虫的取食行为密切相关，但有些 MVOC 也具有很强的驱避作用。微生物原位排放的物质可能会发出与栖息地适宜性或潜在暴露于昆虫病原体有关的信号。在一些生态系统中，细菌或真菌的挥发物也可以引发昆虫聚集，或者 MVOC 可以类似于性信息素，引起反应昆虫的交配和产卵行为。单一的微生物或 MVOC 可以对昆虫行为产生不同的影响，尤其是在不同物种、不同发育阶段和不同栖息地之间。昆虫对 MVOC 的反应似乎存在多方面的基础，并且 MVOC 的产生可以导致复杂的三营养级相互作用。许多微生物物种产生行为活跃的挥发性化合物的生化途径在微生物的大分类群中是保守的。此外，MVOC 具有很大的功能冗余性：真菌组织通常产生聚酮化合物和短链醇，而细菌组织则更常见于胺和吡嗪。我们假设，昆虫对栖息在其感觉环境中的微生物排放物的嗅觉反应比目前所认识的更为普遍，并且这些信号代表了进化上可靠的信息素。昆虫对微生物挥发物的化学感受可能有助于中性、有益甚至有害共生的形成，并为昆虫对挥发性化合物的行为反应的进化提供了重要的见解。
