Pilot study of a new methodology to study the development of the blue bottle fly (<i>Calliphora vomitoria</i>) under exposure to radio-frequency electromagnetic fields at 5.4 GHz

Exposure of insects to radio-frequency electromagnetic fields (RF-EMFs) can have developmental effects. However, there is currently no clear understanding of the exposure level that can lead to such effects. Therefore, the goal of this study was to, for the first time, study the development of the Blue Bottle Fly (<i>Calliphora vomitoria</i>, CV) under exposure to RF-EMFs at 5.4 GHz, using both numerical RF-EMF dosimetry with anatomically accurate 3 D models of insects and an RF-EMF exposure experiment. CV was chosen as a model organism in this study because CV’s development can be influenced thermally and CV’s pupal stage presents a window of several days in which immobile pupae can be exposed to RF-EMFs. The 5.4 GHz frequency was used because it allowed us the license-free operation of the exposure setup. Numerical, EM simulations with 3 D anatomically accurate models of CV, obtained using micro-CT scanning, were used in this study. These simulations enable the estimation of the absorbed power and the whole-body averaged specific absorption rate in CV during RF exposure experiments. An experiment with three exposure conditions was designed and executed in which 400 pupae were split into an exposed group that was placed inside the TEM cell for 48 h and concurrent control. Two exposure conditions used RF-EMF input power into the TEM cell at 5.4 GHz on two different levels. One exposure condition was sham exposure. Electric field strength measurements were used to validate the proper functioning of the exposure setups and to quantify the RF-EMF exposure of the control groups. All studied groups of pupae – exposed to RF-EMFs, sham, and control groups- showed similar (evolutions of) masses, lengths and diameters during their development. The total rate of pupal emergence was reduced in one of the studied RF-EMF exposures in comparison to its concurrent control, while the other RF-EMF exposure and the sham exposure did not alter the total rate of pupal emergence. The sham exposure and the lowest of the two studied RF-EMF exposure conditions (19.4 V/m) caused a median delay in pupal emergence of 4 and 8 hours, respectively, in comparison to concurrent control groups. The higher studied exposure of 55 V/m caused a median relative acceleration in the development of 8 h.昆虫暴露于射频电磁场（radio-frequency electromagnetic fields, RF-EMFs）可对其生长发育产生影响，但目前学界尚未明确可引发此类发育效应的暴露剂量水平。为此，本研究首次结合基于昆虫解剖学精确三维模型的射频电磁场数值剂量学方法与射频电磁场暴露实验，探究5.4 GHz射频电磁场暴露下蓝瓶蝇（Calliphora vomitoria, CV）的生长发育情况。 本研究选取蓝瓶蝇作为模式生物，原因在于其生长发育易受热环境影响，且蛹期长达数日，此时处于静止状态的蛹可便捷开展射频电磁场暴露处理。选用5.4 GHz频段的原因在于，该频段下暴露装置可实现免许可运行。 本研究通过显微CT扫描获取蓝瓶蝇的解剖学精确三维模型，并以此开展电磁场数值仿真，此类仿真可用于估算射频电磁场暴露实验中，蓝瓶蝇体内的吸收功率与全身平均比吸收率（specific absorption rate）。 本研究设计并实施了包含三种暴露条件的实验：将400只蛹分为暴露组与同期对照组，其中暴露组置于横电磁波室（transverse electromagnetic cell, TEM cell）内暴露48小时。两种暴露条件分别为5.4 GHz频段下，向横电磁波室输入不同功率的射频电磁场；第三种为假暴露组。研究通过电场强度测量验证了暴露装置的运行有效性，并量化了对照组所承受的射频电磁场暴露剂量。 所有受试蛹组——射频电磁场暴露组、假暴露组与对照组——在生长发育过程中的体重、体长与体径变化均无显著差异。与同期对照组相比，其中一种射频电磁场暴露条件下的蛹羽化总率有所降低，而另一种射频电磁场暴露条件与假暴露组的蛹羽化总率无明显变化。相较于同期对照组，假暴露组与两种射频电磁场暴露条件中较低剂量组（19.4 V/m）的蛹羽化中位时间分别延迟了4小时与8小时；而剂量较高的55 V/m暴露组则使蛹发育中位时间提前了8小时。