Assessing how air pollution interrupts insect sex pheromone signaling

臭氧(O3)和氮氧化物(NOx)等常见空气污染物可以通过化学方法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健康。在我们最新的NERC资助的研究中，我们设计了一个新的原型野外设施，以调查空气污染物对重要生态过程的影响，特别是授粉。我们的初步结果表明，在臭氧和NOx适度增加的情况下，授粉者探访花卉的次数减少了90%，这表明昆虫授粉受到了出人意料的严重负面影响(相对于实验室研究和模拟模型预测的影响)。最近来自NERC Capital Call的资金使我们能够在这个原型上迭代，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，主要目标是实证调查空气污染如何干扰化学交流。这一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。昆虫使用化学通信进行更广泛的互动，而不是简单地定位花卉资源，例如使用性信息素进行交配定位。我们之前的实验室研究已经证明，性信息素也容易受到空气污染物的化学降解。然而，性信息素和花卉引诱剂操作和传递信息的机制有很大的不同。花信号通常由数十种化合物的混合物组成(其中许多化合物在物种之间普遍存在)，体积相对较大，持续时间较长。相比之下，性信息素通常由几种(通常是1-3种)时间有限的化合物(一旦找到配偶就停止排放)组成，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行为生态造成更大的影响。这个博士项目提供了第一个关于常见空气污染物对昆虫信息素交流影响的机械性实地调查，将由三个不同但相互关联的工作包组成：WP1。柴油废气和臭氧对昆虫探测和定位信息素能力的实地影响(田野生态学)我们由NERC资助的FADOE平台将用不同的生活史策略和信息素化学来量化空气污染对多种昆虫寻找配偶生态的影响。这将使用商业上可获得的信息素诱饵和以活昆虫为诱饵的陷阱来实现。以实验室为基础的机械昆虫行为研究(行为生态学)将在实验室化验中调查WP1中受污染最严重的昆虫，以剖析破坏发生的机制。使用我们新定制的风洞，将研究在不同污染情况下的飞行行为。田间和实验室中信息素变化的化学分析(信息素化学)联系WP1和W2，我们将用化学方法量化气味降解的程度。飞行质谱仪的质子转移反应时间(PTR-TOFMS)将首次在任何研究中被用于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使用气相色谱-质谱法进行。

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.