Assessing how air pollution interrupts insect sex pheromone signaling

常见的空气污染物，如臭氧（O3）和氮氧化物（NOx），可以通过化学方式改变植物和昆虫用于交流的气味化合物，从而间接损害它们的适应性。在我们最新的nerc资助的研究中，我们设计了一个新颖的原型现场设备，以调查空气污染物对重要生态过程的影响，特别是授粉。我们的初步结果发现，在O3和NOx适度增加的情况下，传粉者的访花减少了90%，这表明对昆虫授粉的负面影响出乎意料地严重（相对于实验室研究和模拟模型的预测）。最近来自NERC资本的资助使我们能够对这个原型进行迭代，在雷丁大学的Sonning农场创建一个永久性的自由空气柴油和臭氧浓缩（FADOE）研究平台，主要目标是调查空气污染如何干扰化学通讯。这个全球独一无二的平台将为学生提供前所未有的新研究机会。昆虫利用化学交流进行更广泛的互动，而不是简单地定位花卉资源，例如，利用性信息素定位配偶。我们之前的实验室研究表明，性信息素也容易受到空气污染物的化学降解。然而，性信息素和花引诱剂的作用和传递信息的机制有很大的不同。花的信号通常由几十种化合物（其中许多化合物在物种之间普遍存在）在相当大的体积中在很长一段时间内混合而成。相比之下，性信息素通常由几种（通常是1-3种）暂时有限的化合物组成（一旦找到配偶就停止释放），它们的比例对信号识别至关重要。因此，空气污染对信息素的降解可能会对昆虫的行为生态学产生潜在的更大影响。该博士项目首次对常见空气污染物对昆虫信息素传播的影响进行了机械的实地调查，将包括三个不同但相互关联的工作包：WP1。柴油废气和臭氧对昆虫探测和定向信息素能力的野外影响（野外生态学）我们由nerc资助的FADOE平台将用于量化具有不同生活史策略和信息素化学的多种昆虫物种的空气污染对择偶生态学的影响。这将使用市售的信息素诱捕器和以活昆虫为诱饵的诱捕器来实现。以实验室为基础的昆虫行为机制研究（行为生态学）受WP1污染影响最严重的昆虫将在实验室分析中进行调查，以剖析破坏发生的机制。利用我们全新定制的风洞，我们将研究不同污染情况下的飞行行为。野外和实验室信息素变化的化学分析（信息素化学）连接WP1和2，我们将化学量化气味降解的程度。质子转移反应时间飞行质谱仪（PTR-TOFMS）将用于在任何研究中首次在现场条件下实时分析信号分子的降解。WP2中信息素降解的定量将采用气相色谱-质谱法。

Common air pollutants such as ozone (O3) and nitrogen oxides (NOx) can indirectly impair the fitness of plants and insects by chemically altering the odour compounds that they use for communication. In our latest NERC-funded research, we designed a novel prototype field facility, to investigate the impact of air pollutants upon important ecological processes, particularly pollination. Our preliminary results identified a 90% reduction in flower visitation by pollinators under moderate increases in O3 and NOx, indicating an unexpectedly severe (relative to those predicted by laboratory studies and simulation models) negative impact upon insect-provided pollination.Recent funding from the NERC Capital call is enabling us to iterate upon this prototype to create a permanent Free-Air Diesel and Ozone Enrichment (FADOE) research platform at the University of Reading's Sonning Farm, with the primary goal of investigating empirically how air pollution interferes with chemical communication. This globally unique platform will provide the student with an unprecedented opportunity for novel research.Insects use chemical communication for a broader range of interactions than simply locating floral resources, for example, mate location using sex pheromones. Our previous laboratory research has demonstrated that sex pheromones are also vulnerable to chemical degradation by air pollutants. However, the mechanisms by which sex pheromones and floral attractants operate and convey information differ significantly. Floral signals commonly consist of a mixture of tens of compounds (many of which are ubiquitous between species) in relatively large volume over a long duration. In contrast, sex pheromones are commonly comprised of few (usually 1-3) temporally-limited compounds (emissions cease once a mate is found), whose ratio are critical for signal recognition. Thus, degradation of pheromones by air pollution is likely to result in potentially more dramatic effects upon insect behavioural ecology.This PhD project, providing the first mechanistic field-scale investigation into the effects of common air pollutants on insect pheromone communication, will consist of three distinct but interrelated work packages:WP1. Field-scale impacts of diesel exhaust and ozone on the ability of insects to detect and orient towards pheromones (FIELD ECOLOGY)Our NERC-funded FADOE platform will be used to quantify the impact of air pollution on mate-finding ecology of a broad range of insect species, with differing life history strategies and pheromone chemistry. This will be achieved using both commercially available pheromone lures and traps baited with live insects.WP2. Laboratory-based mechanistic insect behavioural studies (BEHAVIOURAL ECOLOGY)Those insects most disrupted by pollution in WP1 will be investigated in laboratory assays to dissect the mechanisms by which disruption occurs. Using our new custom-built wind-tunnel, in-flight behaviour will be studied under different-pollution scenarios.WP3. Chemical analysis of changes to pheromones in field and laboratory (PHEROMONE CHEMISTRY)Linking WP1 and 2, we will chemically quantify the extent of odour degradation. A Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-TOFMS) will be used to analyse, for the first time in any study, the degradation of signalling molecules in real-time under field conditions. Quantification of pheromone degradation in WP2 will be conducted using gas chromatography-mass spectrometry.